AAP PREP 2009

2009 PREP SA on CD-ROM
Question: 1
You are evaluating a 6-month-old child who has a ventricular septal defect and is scheduled for cardiac
surgery. The child’s weight is 6 kg (3rd percentile), length is at the 30th percentile, and head
circumference is at the 50th percentile. His mother states she prepares the formula by adding 1 scoop
of powder to 2 oz of water. She estimates that he drinks 24 oz of formula per day. You estimate the
baby’s intake is approximately 500 kcal per day of cow milk formula, which is the recommended dietary
allowance (RDA) for his age. According to his mother, he spits up three times a day and passes two
soft stools daily. On physical examination, you hear a 3/6 holosystolic murmur and palpate the liver 1
cm below the right costal margin.
Of the following, the BEST explanation for the child’s malnutrition is
page 1
A. caloric requirements exceeding the RDA
B. cow milk protein intolerance
C. incorrect preparation of the formula
D. pathologic gastroesophageal reflux
E. undiagnosed pancreatic insufficiency

Critique: 1 Preferred Response: A
Children who have large ventricular septal defects, such as described for the child in the vignette, have
increased pulmonary blood flow and may have ventricular hypertrophy and heart failure. Because their
hearts have to work harder, their caloric needs often are increased above the recommended dietary
allowance (RDA) for healthy children. The absence of significant vomiting, diarrhea, or rectal bleeding
suggests that the patient does not have significant gastroesophageal reflux, cow milk protein
intolerance, or pancreatic insufficiency. Incorrect preparation of the formula always should be
considered, but the mother's reported preparation is correct.
The RDA is defined as "a nutrient intake level that is ... sufficient to meet the nutrient requirements of
97% of healthy individuals" in a given group, categorized by sex and age. RDAs are developed by the
Food and Nutrition Board of the Institute of Medicine in collaboration with Health Canada. A full list of
RDAs may be found in many reference textbooks and at the Food and Nutrition Information Center on
the United States Department of Agriculture web site (http://fnic.nal.usda.gov). RDAs estimate energy
requirements of healthy children and do not adjust for chronic illness states that increase caloric needs,
such as cystic fibrosis or congenital heart disease. Children who have chronic illnesses often require
more calories than the RDA to grow and develop.
The estimated daily caloric requirement of a patient is the aggregate of the patient's basal metabolic
rate and physical activity. Various mathematic equations can be used to estimate the daily caloric
intake of children and adults of different ages. Such equations usually take into account the individual's
age, sex, physical activity level, and either the weight and height or, preferably, the body surface area.
For children who have chronic illnesses, more accurate estimates of daily caloric requirements can be
obtained by using a laboratory-based technique, such as indirect calorimetry.
References:
McDaniel NL. Ventricular and atrial septal defects. Pediatr Rev. 2001;22:265-270. Available at:
http://pedsinreview.aappublications.org/cgi/content/full/22/8/265
Sonneville K. Nutritional requirements: dietary reference intakes. In: Hendricks KM, Duggan C. Manual
of Pediatric Nutrition. 4th ed. Hamilton, Ontario, Canada: BC Decker; 2005:83-100
page 2

Question: 2
You are admitting a 750-g female infant to the neonatal intensive care unit (NICU) for treatment of
respiratory distress and presumed sepsis. The pregnancy was complicated by chorioamnionitis and
preterm labor. The infant’s trachea was intubated, a single dose of exogenous surfactant administered,
and both an umbilical venous catheter and umbilical arterial catheter were placed successfully in the
delivery room. In the NICU, the infant is placed on a radiant warmer. The nurse caring for the infant
asks if the infant will need to be transferred to an isolette incubator.
Of the following, the MOST likely reason for this infant to be relocated into an isolette incubator is
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A. avoidance of light damage to the eyes
B. bronzing of the skin under the radiant warmer
C. inability to maintain core temperature on a radiant warmer
D. increased risk for infection under the radiant warmer
E. increased transcutaneous water loss under the radiant warmer

Critique: 2 Preferred Response: E
The extremely low gestational-age newborn (ELGAN) who has a birthweight of less than 1,000 g is at
great risk for transcutaneous evaporative water loss in an open air, nonhumidified environment such as
a radiant warmer. This is most concerning in the first 24 to 72 hours of postnatal life, diminishing
thereafter as the infant's skin becomes cornified. The use of a contained, convectively heated, and
humidified environment can reduce transcutaneous evaporative water loss best in the first few days of
the ELGAN's postnatal life.
Ambient light is not a contributing factor to retinopathy of prematurity, for which the ELGAN is also at
risk. Although excessive thermal warming can occur under the radiant warmer, bronzing of the skin is
related to the use of phototherapy lights in newborns who have conjugated hyperbilirubinemia. The
ELGAN's core temperature can be maintained using a radiant warmer, but evaporative and convective
heat losses remain a concern over lengthy periods of time, and differences in extremity, head, and core
temperatures may affect perfusion and acid-base status. There is no increased risk for infection on the
radiant warmer compared with the isolette incubator.
References:
Dollberg S, Hoath SB. Temperature regulation in preterm infants: role of the skin-environment interface.
NeoReviews. 2001;2:e282-e291. Available for subscription at:
http://neoreviews.aappublications.org/cgi/content/full/2/12/e282
Korones SB. An encapsulated history of thermoregulation in the neonate. NeoReviews.
2004;5:e78-e85. Available for subscription at:
http://neoreviews.aappublications.org/cgi/content/full/5/3/e78
Sedin G. The thermal environment of the newborn infant. In: Martin RJ, Fanaroff AA, Walsh MC, eds.
Fanaroff and Martin's Neonatal-Perinatal Medicine. 8th ed. Philadelphia, Pa: Mosby Elsevier;
2006:585-596
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Question: 3
You are seeing a 1-month-old girl for follow-up after a hospitalization for acute gastroenteritis caused by
rotavirus. Her diarrhea had decreased in the hospital while taking oral rehydration solution, but when
her mother resumed her usual cow milk formula, the girl began to have an increased number of very
watery stools. She appears well hydrated, and findings on her abdominal examination are normal.
Of the following, the MOST appropriate approach to managing this infant’s diarrhea is to
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A. change to a lactose-free formula for the next few days
B. dilute the cow milk formula with oral rehydration solution for the next few days
C. give her only oral rehydration solution until the diarrhea resolves
D. readmit her to the hospital for administration of intravenous fluids
E. repeat her stool studies to confirm the diagnosis of rotavirus infection

The infant described in the vignette most likely has lactase deficiency due to rotavirus infection. Lactase
is an enzyme found in the most superficial villous portion of the intestinal brush border, which
hydrolyzes lactose to glucose and galactose. Lactase deficiency may have several causes in children
and adults. Primary lactase deficiency, the most common type, is a genetically determined condition
that affects children and adults at different ages but is unusual before 5 years. Symptoms include
abdominal distention, bloating, flatulence, or nausea after the ingestion of lactose, with the amount of
lactose needed to cause such symptoms varying from person to person. The diagnosis is made by
breath hydrogen testing, and management consists of removing some or all lactose from the diet.
Congenital lactase deficiency is extremely rare.
Secondary lactase deficiency may develop after an infectious gastroenteritis, such as rotavirus,
giardiasis, or cryptosporidiosis. Other causes include celiac disease and enteropathy related to
immunodeficiency. Secondary lactase deficiency is suggested when a child who has a recent diarrheal
illness experiences worsening diarrhea or bloating after the reintroduction of lactose into the diet, as
described for the girl in the vignette. Most children who have gastroenteritis do not develop lactase
deficiency. For this reason, most infants can tolerate and should continue taking human milk or
standard lactose-containing formula throughout a diarrheal illness. For very young infants (eg, <3
months old), such as the one described in the vignette, or those who have significant fluid losses, a
lactose-free formula may be attempted until the diarrhea resolves. Infants who are breastfed should be
encouraged to continue breastfeeding, even if secondary lactase deficiency is suspected.
Giving full-strength formula or human milk is recommended to supply the child with sufficient calories
during the recovery phase of a diarrheal illness; therefore, diluting the formula or providing only oral
rehydration solution is inappropriate. If the child is not vomiting, oral hydration is optimal, and
intravenous hydration is not necessary. There is no need to confirm the diagnosis of rotavirus infection;
doing so would not alter management plans.
References:
Dalby-Payne J, Elliott E. Gastroenteritis in children. BMJ Clinical Evidence. 2007. Available for
subscription at: http://clinicalevidence.bmj.com/ceweb/conditions/chd/0314/0314.jsp
Heyman MB; Committee on Nutrition. Lactose intolerance in infants, children, and adolescents.
Pediatrics. 2006;118:1279-1286. Available at:
http://pediatrics.aappublications.org/cgi/content/full/118/3/1279
King CK, Glass R, Bresee, Duggan C. Managing acute gastroenteritis among children: oral rehydration,
maintenance, and nutritional therapy. MMWR Morbid Mortal Wkly Rep Recomm Rep.
2003;52(RR-16):1-16. Available at: http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5216a1.htm
page 6

Question: 4
During a prenatal visit with expectant parents, they report that they are strict vegans. They ask you to
advise them on a healthy diet and any required supplements. The mother plans to breastfeed the
newborn exclusively for the first 6 months.
Of the following, you are MOST likely to tell them that their newborn may require supplemental
A. calcium
B. folate
C. iron
D. vitamin B6
E. vitamin B12
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A vegan diet, by definition, excludes all foods derived from animal products. A lacto-ovo-vegetarian diet
may include milk and eggs. Although a vegan diet may be healthy, there is a risk for vitamin B12
deficiency because vitamin B12 is only found in foods of animal origin. Breastfeeding vegan mothers
may produce milk that is deficient in this vitamin and require supplementation that generally is achieved
by continuing the consumption of prenatal vitamins containing vitamin B12.
The recommended supplementation for breastfed vegan infants to prevent vitamin B12 deficiency is
0.4 mcg/day during the first 6 postnatal months and 0.5 mcg/day from 6 months to 1 year of age. Vegan
infants who are not breastfed should receive iron-fortified soy infant formula until 1 year of age to avoid
deficiencies in iron. Vegan infants require no other mineral or vitamin supplementation.
Vegan diets in older children and adolescents may be low in calcium (similar to the typical American
"teenage diet" that contains less than the recommended intake of dairy products), and the zinc
consumption may be relatively low due to the absence of phytate, which renders zinc more bioavailable.
Children who follow vegan diets may have relatively diminished overall energy intake because such
diets commonly are low in fat and high in fiber.
Review of nutrient intake and energy intake in conjunction with growth curves of children eating
vegan diets in both the United States and the United Kingdom demonstrate no significant health issues.
Height and weight measured in vegan populations may be slightly lower than average but not in the
range of failure to thrive or short stature. Adolescents eating vegan diets are more likely than
adolescents eating a typical American diet to meet nutritional goals, including recommended intake of
fruits and vegetables. Vegan adolescents are less likely to be obese because they consume fewer
foods high in fat. However, they remain at risk for vitamin B12 deficiency and should consume at least a
daily multivitamin. They are less likely to have anemia but just as likely to have low calcium intake as
their non-vegan peers. Adolescents who follow a lacto-ovo-vegetarian diet are less likely to have
deficiencies in vitamin B12, calcium, and iron.
Folate and vitamin B6 are not likely to be deficient in persons who consume vegan diets because
those nutrients are found in many legumes, fruits, and vegetables that are the mainstays of the diet.
References:
Kleinman RE. Nutritional aspects of vegetarian diets. In: Pediatric Nutrition Handbook. 5th ed. Elk
Grove Village, Ill: American Academy of Pediatrics; 2003:191-208
Mangels AR, Messina V. Considerations in planning vegan diets: infants. J Am Diet Assoc.
2001:101:670-677. Abstract available at: http://www.ncbi.nlm.nih.gov/pubmed/11424546
Messina V, Mangels AR. Considerations in planning vegan diets: children. J Am Diet Assoc.
2001:101:661-669. Abstract available at: http://www.ncbi.nlm.nih.gov/pubmed/11424545
Moilanen BC. Vegan diets in infants, children and adolescents. Pediatr Rev. 2004:25:174-176.
Available at: http://pedsinreview.aappublications.org/cgi/content/full/25/5/174
Perry CL, McGuire MT, Neumark-Sztainer D, Story M. Adolescent vegetarians: how well do their dietary
patterns meet the Healthy People 2010 objectives? Arch Pediatr Adolesc Med. 2002; 156:431-437.
Available at: http://archpedi.ama-assn.org/cgi/content/full/156/5/431
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Question: 5
You are treating a child who has suffered a splenic injury and is being transfused with large volumes of
packed red blood cells for severe anemia. He weighs 10 kg and has received 4 units thus far.
Of the following, the finding on electrocardiography that is MOST likely to represent a serious
complication of his therapy is
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A. atrial flutter
B. delta waves
C. prominent U waves
D. supraventricular tachycardia
E. tall-peaked T waves

Administration of fluids and blood products can be essential for resuscitation of the trauma patient but
may lead to potentially dangerous electrolyte imbalances. Recognition of these abnormalities, which
may be subtle, can be important and even lifesaving. When large volumes of blood are transfused, as
reported for the child in the vignette, hyperkalemia may occur, which is believed to be the result of
extravasation of potassium from the red blood cells that have been irradiated and stored over time.
Hyperkalemia can be associated with paresthesias, weakness, and tingling, although cardiac toxicity
typically precedes such symptoms. Severe cardiac rhythym changes may begin abruptly. The classic
electrocardiographic sign of hyperkalemia is tall, peaked T waves (Item C5A), particularly as the serum
potassium concentration approaches or exceeds 5.0 to 6.0 mEq/L (5.0 to 6.0 mmol/L). As hyperkalemia
progresses, other changes in the ECG, such as widening of the QRS complex, may be noted. The
rhythm changes that occur as a result of hyperkalemia, including ventricular arrhythmias, may develop
abruptly, leading to sudden changes in the patient's clinical condition.
Another potential electrolyte complication of fluid and blood administration is hypocalcemia, which
results from the citrate-containing anticoagulants that bind free calcium. Hypocalcemia may manifest on
ECG as a prolonged QT interval, which tends to widen as the ionized calcium concentrations decrease.
Atrial flutter, a primary disease of the atrial tissue, would not be expected in the patient described in
the vignette. The delta wave refers to the ECG finding of pre-excitation, seen in conditions such as the
Wolff-Parkinson-White syndrome that have an associated "bypass" tract allowing for excitement of the
His-Purkinje system without passage through the atrioventricular node (Item C5B).
The U wave may be seen in hypokalemia (Item C5C), particularly as concentrations decrease below
2.7 mEq/L (2.7 mmol/L), or hypercalcemia (calcium concentrations exceeding 12.0 mg/dL [3.0 mmol/L]),
which would not be expected in the patient described in the vignette. Hypercalcemia also may lead to a
diminished QT interval, and with more severe hypercalcemia, second- or third-degree heart block (Item
C5D) may develop. Supraventricular tachycardia (Item C5E) would not be expected to occur as a result
of a large-volume transfusion process.
References:
Galel SA, Naiman JL. Use of blood and blood products. In: Rudolph CD, Rudolph AM, eds. Rudolph's
Pediatrics. 21st ed. New York, NY: McGraw-Hill Medical Publishing Division; 2003:1576-1581
Vetter V. Arrhythmias. In: Moller JH, Hoffman JIE, eds. Pediatric Cardiovascular Medicine. Philadelphia,
Pa: Churchill Livingstone; 2000:833-884
page 10

page 11
Critique: 5
The electrocardiogram in hyperkalemia shows peaked T waves. (Courtesy of
A. Friedman)

page 12
Critique: 5
In Wolff-Parkinson-White syndrome, delta waves (arrows) are present that
represent pre-excitation depolarization of the QRS complex. (Courtesy of A.
Friedman)

page 13
Critique: 5
The U wave (arrow) may be observed in hypokalemia (shown here in which
there is also ST depression and flattening of the T wave) or hypercalcemia.
(Courtesy of A. Friedman)

page 14
Critique: 5
In third-degree heart block that may result from severe hypercalcemia, P
waves are completely dissociated from QRS complexes. (Courtesy of A.
Friedman)

page 15
Critique: 5
Narrow complex tachycardia that is consistent with supraventricular
tachycardia or paroxysmal atrial tachycardia. (Courtesy of A. Friedman)

Question: 6
A 15-year-old girl presents to the emergency department with a 4-week history of nasal drainage and
face pain and a 2-week history of frontal headaches and fatigue. Her mother complains that her
daughter has an "attitude" and has not been respectful or seemed to care about anything for the past 2
weeks. The daughter awoke this morning with a headache and vomited. On physical examination, the
adolescent is afebrile and has normal vital signs. She responds slowly to questions and is not oriented
to the date. She complains of pain to palpation of her cheeks and forehead. She has no nuchal rigidity
and no focal weakness. The remainder of the physical examination findings are normal.
Of the following, the BEST initial diagnostic procedure is
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A. computed tomography scan of the head with intravenous contrast
B. emergent electroencephalography to rule out nonconvulsive status epilepticus
C. lumbar puncture to rule out meningitis
D. nasal swab for bacterial culture
E. urine drug screen for barbiturates, amphetamines, and cocaine

The subacute onset of mental status changes described for the adolescent in the vignette warrants an
emergency evaluation. In most cases, neuroimaging is indicated, along with appropriate laboratory
testing.
The relatively nonspecific pain and what her mother perceives as common emotional problems
(apathy in a teenager) probably represent early frontal lobe symptoms. The headache on awakening
and vomiting are concerning for increased intracranial pressure (ICP). Confusion and psychomotor
retardation on the mental status examination indicate involvement of the central nervous system. A
focal, ischemic, ictal, infectious/inflammatory, or toxic/metabolic process must be identified urgently. A
brain abscess is suggested by the prominent facial pain in this setting; the sinuses are a common
source of brain abscesses (Item C6). Brain abscesses often present only with nonspecific pain and not
with fever.
Head computed tomography (CT) scan is preferred for this patient because the constellation of pain,
confusion, and morning vomiting makes a focal intracranial mass a possibility. Increased ICP is
associated with morning vomiting because ICP is highest in the morning. Contrast is recommended
because of the insidious onset, which could indicate either a neoplasm or infectious process.
Intravenous contrast is not needed for all neuroimaging procedures. However, it increases the
diagnostic yield of imaging studies where either neoplasm or infection is suspected because both
typically involve some degradation of the blood-brain barrier or hypervascularity, resulting in contrast
enhancement at the site of the lesion. Magnetic resonance imaging (MRI) with contrast also is a good
choice. The advantage of MRI is higher spatial and soft-tissue resolution. Disadvantages of MRI
compared with CT include: 1) less availability for emergency department studies; 2) need for
pharmacologic sedation in agitated patients because sedation affects mental status, thereby masking
disease-related mental status; 3) longer time in the scanner, which could delay treatment decisions;
and 4) cost. Thus, in most cases, a head CT scan with contrast is preferred as the initial study in the
emergency department.
page 17
Electroencephalography (EEG) is an important test for assessment of a patient who has
encephalopathy of unclear cause to rule out nonconvulsive status epilepticus (NCSE), particularly if the
patient is known to have epilepsy. If an EEG cannot be obtained rapidly, intravenous administration of
0.1 mg/kg lorazepam can treat NCSE immediately, although this would not clear confusion about other
causes. For this adolescent, the facial pain makes the diagnosis of NCSE less likely than a brain
abscess.
A lumbar puncture may be needed to rule out meningitis or encephalitis, but the pain and morning
vomiting more strongly suggest the possibility of an intracranial mass. Lumbar puncture prior to head
CT is not advised in this case because it could reduce pressure below the foramen magnum and result
in herniation from the supratentorial mass. Toxicology screening and nasal swabs are reasonable but
not the preferred initial diagnostic tests because they will not affect emergency management of the
increased intracranial pressure.
References:
Goodkin HP, Harper MB, Pomeroy SL. Intracerebral abscess in children: historical trends at Children's
Hospital Boston. Pediatrics. 2004;113:1765-1770. Available at:
Haslam RHA. Brain abscess. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson
Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:2524-2525

Kan L, Nagelberg J, Maytal J. Headaches in a pediatric emergency department: etiology, imaging, and
treatment. Headache. 2000;40:25-29. Abstract available at:
http://www.ncbi.nlm.nih.gov/pubmed/10759899
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page 19
Critique: 6
Brain abscess: Contrast-enhanced computed tomography scan of the head
reveals a rim-enhancing lesion extending to an area of bony destruction in an
opacified left frontal sinus. Vasogenic edema surrounding the abscess
creates a mass effect and shift of the midline to the right. (Courtesy of D.
Krowchuk)

Question: 7
A 5-year-old girl who is new to your practice presents to the clinic for a prekindergarten physical
examination. Her primary caretaker, the maternal grandmother, reports that the child’s mother used
multiple street drugs throughout her pregnancy as well as medications prescribed for seizure and
bipolar disorders. The grandmother is concerned that this child’s speech development is delayed. On
physical examination, you note that the girl has wide-spaced eyes, a short nose, and midface
hypoplasia.
Of the following, the substance that is MOST likely to be associated with this child’s dysmorphic
features is
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A. lithium
B. lysergic acid diethylamide (LSD)
C. marijuana
D. methamphetamine
E. phenobarbital

The features described for the child in the vignette are most consistent with fetal anticonvulsant
syndrome, which can occur following exposure to numerous medications, including phenytoin,
carbamazepine, valproate, and phenobarbital. Multiple authors have observed a 10% to 20% incidence
of birth defects in infants exposed to phenobarbital in utero. Anomalies include midface hypoplasia,
ocular hypertelorism (Item C7A), nail hypoplasia (Item C7B), cleft lip+/-cleft palate, and heart defects as
well as developmental delay and pre- and postnatal growth failure.
page 21
Phenobarbital-exposed newborns may exhibit a withdrawal syndrome that is evidenced by
tremulousness and increased activity. Of interest, such infants are likely to have lower serum bilirubin
concentrations than nonexposed neonates.
Prenatal exposure to lithium is associated with an increased risk of cardiac malformations (eg,
Ebstein anomaly) in the fetus. If the mother takes lithium near term, the exposed neonate may have
cyanosis, hypotonia, abnormalities of cardiac rhythm, goiter, hypothyroidism, and nephrogenic diabetes
insipidus. Lithium exposure is not associated with dysmorphic features or developmental delays.
Despite popular belief, lysergic acid diethylamide (LSD) generally is not associated with birth defects
or withdrawal symptoms in prenatally exposed infants. Although there are isolated case reports of birth
defects in exposed neonates, an increased risk for anomalies is not borne out by epidemiologic studies.
It is important to note, however, that LSD users often abuse other substances, underscoring the
importance of taking an in-depth drug/substance abuse history in pregnant women.
Marijuana use during pregnancy is not known to be associated with an increased incidence of birth
defects, dysmorphic features, or developmental delay in exposed offspring, although further study is
needed in this regard. Some investigations have shown reduced fetal growth in exposed pregnancies,
but this is not confirmed. Prenatally exposed newborns may have tremulousness, increased irritability,
and abnormal visual response to light stimulus.
Although there does not appear to be an increase in congenital anomalies associated with
methamphetamine use during pregnancy, further study is necessary. There are reports of decreased
birthweight in exposed neonates. A neonatal withdrawal syndrome consisting of abnormal sleep
patterns, tremulousness, poor feeding, and increased tone has been observed commonly. Once again,
it is important to consider polydrug abuse in these instances.
As with all teratogens, the timing of exposure is critical, with the most vulnerable period of embryonic
development occurring between 18 and 60 days after conception, during organogenesis. Dosage of the
offending agent also is important, as are route of administration, modifying environmental factors, and
genetic background of the mother and fetus.
References:
Gallagher RC, Kingham K, Hoyme HE. Fetal anticonvulsant syndrome. In: Cassidy SB, Allanson JE,
eds. Management of Genetic Syndromes. 2nd ed. Hoboken, NJ: Wiley-Liss; 2005:239-250
Phenobarbital, lithium, LSD, marijuana, methamphetamine. Reprotox. Available for subscription at:
http://www.reprotox.org
Phenobarbital, lithium, LSD, marijuana, methamphetamine. Teris. Available for subscription at:
http://depts.washington.edu/terisweb/teris

page 22
Critique: 7
Wide-spaced eyes and a short upturned nose are facial features of the fetal
anticonvulsant syndrome. This child was exposed to phenytoin. (Courtesy of
M. Rimsza)

page 23
Critique: 7
Nail hypoplasia is observed in a child who has fetal anticonvulsant syndrome.
(Courtesy of the Media Lab at Doernbecher)

Question: 8
A 15-year-old girl comes to the urgent care clinic complaining of lower abdominal pain for 48 hours. She
is nauseated but has had no fever, vomiting, or diarrhea. She is afebrile and denies abdominal trauma.
She localizes the pain to the left lower quadrant and describes it as intermittent, stabbing pain episodes
separated by intervals of more continuous dull pain. She has never been sexually active. Her last
menstrual period was 1 week ago. She has had no vaginal discharge or itching. On physical
examination, she has left lower quadrant guarding and rebound tenderness. Her pelvic examination
shows no vaginal discharge or uterine tenderness, although there is an exquisitely tender mass in the
left adnexal area.
Of the following, the MOST likely diagnosis is
page 24
A. appendicitis
B. endometritis
C. ovarian torsion
D. sacroiliitis
E. splenic rupture

Critique: 8 Preferred Response: C
Torsion of any adnexal structure, including the ovary, can result in an acute pelvic mass (Item C8). The
most common causes of adnexal torsion in young women are cysts and neoplasms, with about 6% of
torsions in one series occurring in the setting of normal-appearing ovaries. Histopathology was benign
in more than 90% of cases in this series. Torsion occurs when masses cause the ovary to swing on its
vascular pedicle, and larger masses generally are associated with a greater potential for torsion until
the size of the mass impedes movement. The onset of pain associated with torsion can be abrupt,
sharp, and very severe. However, with intermittent or partial torsion, intense periods of intermittent pain
may be separated by generalized aching during detorsion, as described for the teenager in the vignette.
Pain can occur for several days or weeks prior to a complete torsion. Nausea or vomiting can
accompany severe pain. If adnexal torsion is diagnosed, prompt intervention (untwisting the adnexa
usually via laparoscopy) is indicated to preserve ovarian function.
Appendicitis is in the differential diagnosis for lower abdominal pain, but is less likely when pain
occurs in the left lower quadrant. Splenic rupture is a surgical emergency, like ovarian torsion, but the
finding of an adnexal mass on examination is unlikely. Endometritis is not very likely in a young woman
who is not sexually active and more commonly presents with midline uterine pain. An orthopedic cause
for this patient's pain (eg, sacroiliitis) is unlikely, but it remains in the differential diagnosis of pelvic pain.
Sacroiliitis usually presents with low back or hip pain.
References:
Adams Hillard PJ. Pelvic masses. In: Neinstein LS, eds. Adolescent Health Care: A Practical Guide. 5th
ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2008:706-713
Growdon WB, Laufer MR. Ovarian torsion. UpToDate Online 15.3. 2008. Available for subscription at:
http://www.utdol.com/utd/content/topic.do?topicKey=gyn_surg/5273
Laufer MR, Goldstein DP. Gynecologic pain: dysmenorrhea, acute and chronic pelvic pain,
endometriosis, and premenstrual syndrome. In: Emans SJH, Laufer MR, Goldstein DP, eds. Pediatric
and Adolescent Gynecology. 5th ed. Philadelphia, Pa: Lippincott, Williams & Wilkins; 2005:417-476
Varras M, Tsikini A, Polyzos D, Samara Ch, Hadjopoulos G, Akrivis Ch. Uterine adnexal torsion:
pathologic and gray-scale ultrasonographic findings. Clin Exp Obstet Gynecol. 2004;31:34-38. Abstract
available at: http://www.ncbi.nlm.nih.gov/pubmed/14998184
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page 26
Critique: 8
Ovarian torsion: Color flow Doppler ultrasonography of the right ovary shows
abundant flow in the adjacent pelvic tissue (blue, red, and orange color seen
inferiorly) but none in the ovary (the area within the dashed line).

Question: 9
A 2-year-old boy who has chronic renal failure is brought to the emergency department for evaluation of
nausea, fatigue, and muscle weakness. On physical examination, the boy has a heart rate of 140
beats/min, decreased perfusion, and palpable pulses. You obtain electrocardiography (Item Q9).
Electrolyte measurements include a potassium concentration of 7.5 mEq/L (7.5 mmol/L) and a glucose
value of 72.0 mg/dL (4.0 mmol/L).
Of the following, the MOST appropriate initial treatment is administration of
page 27
A. calcium chloride
B. insulin
C. normal saline 20 mL/kg
D. sodium polystyrene sulfonate
E. verapamil

page 28
Question: 9
In hyperkalemia, electrocardiography demonstrates peaked T waves.

Hyperkalemia can be asymptomatic or produce symptoms such as nausea, fatigue, and muscle
weakness, as reported for the boy in the vignette. The most concerning effect of hyperkalemia is on
cardiac membrane polarization. Electrocardiographic changes typically consist of peaked T waves and
progress to widening of the QRS complexes with dampening of P waves as the hyperkalemia
increases. Without treatment, the patient eventually develops ventricular fibrillation or asystole.
The electrocardiographic tracing of the boy described in the vignette demonstrates peaked T waves
(Item C9), and he has decreased perfusion. The immediate priority is to stabilize his cardiac membrane
potential and decrease his risk of arrhythmias, which is accomplished best by administration of
intravenous calcium chloride, an agent that has a rapid onset of action. Insulin causes potassium to
shift to the intracellular spaces, thereby decreasing serum concentrations, but it always should be
administered in conjunction with glucose to avoid hypoglycemia. Sodium bicarbonate administered
intravenously also produces intracellular shifts of potassium and may be useful in patients who have
metabolic acidosis.
page 29
Treatments to enhance the elimination of potassium often are indicated in the treatment of
hyperkalemia, but they have a slower onset of action and, therefore, should not be the first line of
treatment in life-threatening hyperkalemia. Sodium polystyrene sulfonate, which can be administered
orally or rectally, exchanges sodium for potassium, which subsequently is eliminated from the body.
Loop diuretics also can enhance potassium elimination. Dialysis may be indicated when ongoing
elevated potassium concentrations are expected, such as in renal failure, or with very high acute
concentrations, as seen with tumor lysis syndrome or rhabdomyolysis.
Administration of verapamil is not indicated in the treatment of hyperkalemia; it has been reported to
be associated with the development of complete heart block in this setting. Normal saline has a minimal
effect on hyperkalemia.
References:
Greenbaum LA. Electrolyte and acid-base disorders: potassium. In: Kliegman RM, Behrman RE,
Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders
Elsevier; 2007:279-284
Hauser GJ, Kulick AF. Electrolyte disorders in the pediatric intensive care unit. In: Wheeler DS, Wong
HR, Shanley TP, eds. Pediatric Critical Care Medicine: Basic Science and Clinical Evidence. New York,
NY: Springer-Verlag; 2007:1156-1175

page 30
Critique: 9
In hyperkalemia, electrocardiography demonstrates peaked T waves.

Question: 10
A 13-year-old girl who has just moved to the United States from Brazil comes to your office because her
mother is worried that she is not "developing yet." On physical examination, her height is 50 inches, and
she has a triangular face, a low hairline, high-arched palate, and a shield-shaped chest (Item Q10).
Breast tissue is not visible or palpable, but there is Sexual Maturity Rating 3 pubic hair. You obtain bone
age radiography and a karyotype and measure serum luteinizing hormone and follicle-stimulating
hormone.
Of the following, the MOST appropriate additional laboratory measurement is
page 31
A. adrenocorticotropic hormone
B. prolactin
C. 17-hydroxyprogesterone
D. testosterone
E. thyroid-stimulating hormone

page 32
Question: 10
Shield-shaped chest and lack of breast development, as described for the girl
in the vignette. (Courtesy of M. Rimsza)

The clinical findings described for the girl in the vignette are characteristic of Turner syndrome (gonadal
dysgenesis) associated with an abnormality of one X chromosome. Girls who have this disorder usually
are short (mean adult height, approximately 55 inches without growth hormone treatment); have poorly
developed ovaries; and often have dysmorphisms, including a triangular facies, low hairline,
high-arched palate, hypoplastic nipples, and an increased carrying angle. They may have left heart
disorders such as coarctation of the aorta as well as horseshoe kidney or other renal malformations.
Initial screening studies to diagnose Turner syndrome include a karyotype and measurement of
luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Most girls who have Turner syndrome
do not initiate normal puberty. Concentrations of LH and FSH rise as they reach pubertal age range
because they have ovarian failure. Although concentrations of estradiol and other estrogens are low,
clinical estradiol assays are not designed to provide accurate values in the low-normal range expected
in early puberty. Therefore, physical findings such as breast development are a better marker of
estrogen effect than measurements of estrogen.
page 33
Adolescents who have Turner syndrome are at higher risk of developing chronic lymphocytic
thyroiditis and hypothyroidism than the general population. Approximately 20% of affected adolescent
girls have antibody-positive autoimmune chronic lymphocytic thyroiditis, and 5% to 10% develop overt
hypothyroidism. Accordingly, measurement of thyroid-stimulating hormone is an appropriate laboratory
test for patients such as the girl described in the vignette. An elevated value indicates primary
hypothyroidism and the need for confirmatory assessment of free thyroxine and antithyroid antibodies
(thyroperoxidase, antimicrosomal, or antithyroglobulin).
Abnormalities of the hypothalamic-pituitary-adrenal axis are unusual in patients who have Turner
syndrome. Therefore, measurement of adrenocorticotropic hormone is not useful. Measurement of
prolactin would be useful if the girl had a pituitary or hypothalamic problem, but her clinical findings
strongly point to Turner syndrome. A 17-hydroxyprogesterone value would be elevated in the presence
of an adrenal biosynthetic defect leading to the development of the most common form of congenital
adrenal hyperplasia (cyp21 or 21-hydroxylase deficiency) as well as some of the less common
disorders of adrenal biosynthesis. Measuring testosterone would be reasonable if there were evidence
of inappropriate masculinization, such as clitoromegaly and a growth spurt. Some girls who have Turner
syndrome have functioning Y chromosomal DNA and could have androgenization, but this is unusual.
The presence of Y chromosomal DNA does increase the risk of gonadal malignancy, and girls who
have significant Y chromosomal DNA on testing often require prophylactic gonadectomy.
References:
Chiovato L, Larizza D, Bendinelli G, et al. Autoimmune hypothyroidism and hyperthyroidism in patients
with Turner's syndrome. Eur J Endocrinol. 1996;134:568-575. Abstract available at:
Doswell BH, Visootsak J, Brady AN, Graham JM Jr. Turner syndrome: an update and review for the
primary pediatrician. Clin Pediatr. 2006;45:301-313. Abstract available at:
Frias JL, Davenport ML, Committee on Genetics and Section on Endocrinology. Health supervision for
children with Turner syndrome. Pediatrics. 2003;111:692-702. Available at:
Matura LA, Ho VB, Rosing DR, Bondy CA. Aortic dilatation and dissection in Turner syndrome.

Circulation. 2007;116:1663-1670. Abstract available at: http://www.ncbi.nlm.nih.gov/pubmed/17875973
Sybert VP, McCauley E. Turner's syndrome. N Engl J Med. 2004;351:1227-1238. Extract available at:
http://content.nejm.org/cgi/content/extract/351/12/1227
Turner Syndrome Society Website. Available at: http://www.turnersyndrome.org
page 34

page 35
Question: 11
A 2-month-old infant has lost the vision in both of his eyes due to bilateral retinoblastoma. His
distressed parents ask how the infant’s blindness will affect his behavior and development.
Of the following, the child MOST likely will
A. begin saying single words at 16 to 20 months
B. begin walking between 18 and 22 months
C. display behaviors of an autism spectrum disorder
D. have a language-based learning disorder
E. have significant cognitive impairments

Critique: 11 Preferred Response: B
Legal blindness is defined as central visual acuity with corrective lenses of 20/200 or less in the
strongest eye or a limited visual field that extends to an angle of 20 degrees. Congenital blindness
occurs in 30 per 100,000 births. More than 50% of children who have visual impairment also have
developmental disabilities, such as cognitive-adaptive disability, seizures, hearing impairments, and
learning disorders. In many of these cases, the disabilities result from central nervous system
pathology. Postnatal blindness, which accounts for approximately 8% to 11% of all childhood blindness,
can be caused by infections, trauma, or tumors. Retinoblastoma is the most common primary malignant
intraocular tumor of childhood. The initial finding in most cases is a white pupillary reflex (leukokoria)
(Item C11). Advanced tumors may be treated with enucleation.
Children who have congenital or acquired (eg, due to retinoblastoma) blindness without associated
neurologic abnormalities should not be at increased risk for motor or cognitive impairment. They are not
at increased risk for language-based learning disabilities or autism spectrum disorders. However,
children who have significant visual impairment may begin to walk at an older age (18 to 22 months)
than sighted children due to different exposure to motor exploration. They typically develop language
skills at the same time (12 months) as sighted children. Children who have visual impairments should
be provided with much physical contact that includes hugging and comforting. They should be
encouraged to partake in self-help skills and exploration of their environment.
References:
Davidson PW, Burns CM. Visual impairment and blindness. In: Levine MD, Carey WB, Crocker AC,
eds. Developmental- Behavioral Pediatrics. 3rd ed. Philadelphia, Pa: WB Saunders Company;
1999:571-578
Msall ME. Visual impairment. In: Parker S, Zukerman B, Augustyn M. Developmental and Behavioral
Pediatrics: A Handbook for Primary Care. 2nd ed. Philadelphia, Pa: Lippincott Williams & Wilkins;
2005:366-369
Olitsky SE, Hug D, Smith LP. Disorders of vision. In: Kleigman RM, Behrman RE, Jenson HB, Stanton
BF, eds. Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:2573-2576
page 36

page 37
Critique: 11
Leukokoria may be observed in patients who have retinoblastoma. (Courtesy
of R.G. Weaver, Jr)

Question: 12
A 15-year-old boy presents to the clinic because of a persistent cough. According to his mother, his
cough has been present for approximately 2 weeks, but it seems to be getting worse. He does not
cough all the time, but the coughing episodes tend to come in bursts. This morning she became very
worried because he passed out during a coughing spell. Physical examination reveals a
healthy-appearing male in no apparent distress. He is afebrile, and his vital signs are normal. He has
petechiae on his face but no other skin lesions. His lungs are clear.
Of the following, the MOST appropriate antimicrobial agent to prescribe for this patient is
page 38
A. azithromycin
B. clarithromycin
C. doxycycline
D. erythromycin
E. trimethoprim-sulfamethoxazole

Any patient who has episodic coughing episodes that conclude in syncope or vomiting, such as the boy
described in the vignette, should be considered to have pertussis. Other complications from pertussis
described in adolescents include urinary incontinence, sleep interruption, rib fractures, and pneumonia.
Despite universal immunization of children against pertussis, a marked increase in disease incidence
has been demonstrated among adolescents of 11 to 18 years of age. In an attempt to address this
problem, the American Academy of Pediatrics recommends that adolescents in this age group receive
a single dose of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) for booster
immunization. For those who received only a tetanus toxoid and reduced diphtheria toxoid (Td) booster,
a booster with Tdap is suggested if the interval since the Td administration is at least 2 years or if the
adolescent is living in a setting of increased disease, has a risk of a complicated course if he or she
acquires the disease, or possibly can transmit infection to a vulnerable contact.
Treatment of pertussis with antimicrobial agents once the cough has started does not affect the
course of the illness but is recommended to limit the spread of disease to others. In the past, the
treatment of choice was erythromycin, but recent data have demonstrated that the effectiveness of
other macrolides such as azithromycin or clarithromycin is similar to that of erythromycin, and they have
fewer adverse effects. The most common complaints of patients who take erythromycin preparations
are gastrointestinal irritation, including epigastric distress, abdominal cramping, nausea, vomiting, and
diarrhea. The occurrence of these adverse effects can result in poor adherence to treatment regimens.
In addition, erythromycin cannot be used in children younger than 1 month of age due to its association
with the development of hypertrophic pyloric stenosis. Azithromycin and clarithromycin attain higher
tissue concentrations than erythromycin, have longer half-lives, and can be administered less often and
for a shorter total duration. With the advent of these newer macrolides, erythromycin rarely is indicated
as a first-line agent for any illness.
Azithromycin has become the agent of choice for treatment of pertussis because of the ease of
administration (once daily for 5 days) and the fact that it does not inhibit cytochrome P-450, as
erythromycin and clarithromycin do. Therefore, it does not interact with other medications that are
metabolized by this system (eg, digoxin, carbamazepine). Trimethoprim-sulfamethoxazole also is
effective against pertussis and is considered an alternative for patients who cannot tolerate a macrolide
or have a macrolide-resistant isolate if they are older than 2 months of age. Doxycycline is not
recommended for the treatment of pertussis.
References:
American Academy of Pediatrics. Pertussis (whooping cough). In: Pickering LK, Baker CJ, Long SS,
McMillan JA, eds. Red Book: 2006 Report of the Committee on Infectious Diseases. 27th ed. Elk Grove
Village, Ill: American Academy of Pediatrics; 2006:498-520
Committee on Infectious Diseases. Prevention of pertussis among adolescents: recommendations for
use of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine. Pediatrics.
2006;117:965-978. Available at: http://pediatrics.aappublications.org/cgi/content/full/117/3/965
Tiwari T, Murphy TV, Moran J. Recommended antimicrobial agents for the treatment and postexposure
prophylaxis of pertussis: 2005 CDC guidelines. MMWR Recomm Rep. 2005;54(RR14):1-16. Available
at: http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5414a1.htm
page 39

Question: 13
A 15-year-old male presents for evaluation of a progressively enlarging lesion on his left forearm that
began 5 days ago. He explains that the lesion initially looked like a "spider bite" with a blister, but over
the last several days, a black scab has developed in the center of the lesion, and there is a large area
of redness around the scab. The lesion has been pruritic but not painful. Except for low-grade fevers for
the last 2 days, he has had no other systemic symptoms. He returned 1 week ago from a school trip to
Morocco, where he visited a leather tannery, went shopping in the large outdoor marketplace, visited
some historic sites, and took a camel ride in the desert. He states that the students stayed in a hostel in
Morocco, but there were no screens on the windows, and spiders, ants, and other insects were visible
in the rooms. On physical examination, the boy is afebrile, and his left forearm is edematous, with a
3x3-cm black eschar surrounded by a 5-cm area of erythema and induration (Item Q13). The lesion is
not tender to palpation, and there is no drainage. There are several 1.5-cm tender lymph nodes in his
left axilla. Findings on the remainder of his examination are within normal limits.
Of the following, the MOST likely cause of this patient’s lesion is
page 40
A. Bacillus anthracis
B. Francisella tularensis
C. Loxosceles laeta
D. methicillin-resistant Staphylococcus aureus
E. Yersinia pestis

page 41
Question: 13
Eschar, as desribed for the patient in the vignette. (Courtesy of the Centers for
Disease Control and Prevention, Public Health Image Library, James H. Steele)

Anthrax is a zoonotic disease caused by Bacillus anthracis, which is a gram-positive, encapsulated,
spore-forming rod that occurs in many areas of the world. B anthracis spores can remain viable in the
soil for decades (Item C13A), representing a major reservoir of infection for herbivorous livestock
through ingestion. Human infection occurs through contact with infected animals or contaminated
animal products, including carcasses, hides, hair, wool, meat, bone meal, and other contaminated
foodstuffs.
page 42
Depending on the route of infection, anthrax disease may manifest in three different forms:
cutaneous, inhalational, and gastrointestinal. Approximately 95% of all human anthrax cases are
cutaneous anthrax. The incubation period of cutaneous anthrax is 1 to 12 days. The initial skin lesion is
a pruritic papule that resembles an insect or spider bite, as described for the boy in the vignette. The
papule progresses to the development of a central vesicular or bullous lesion that becomes necrotic
and hemorrhagic and forms a central black painless eschar, which is the classic lesion of anthrax (Item
C13B). There is marked surrounding edema, swelling, induration, and erythema of the involved area but
no associated tenderness. Regional lymphadenopathy, fever, malaise, and headache also may be
present. In most cases, the eschar falls off in 1 to 2 weeks, and total resolution occurs in 6 weeks.
Infections caused by methicillin-resistant Staphylococcus aureus (MRSA), the bite of Loxosceles
laeta, Francisella tularensis, and Yersinia pestis are associated with pain, rapid progression, and in
most cases, systemic symptoms. Skin and soft-tissue infections due to MRSA have been described as
resembling a "spider bite" that is very tender, with progressive worsening of the erythema, warmth, and
tenderness (Item C13C). It is not associated with the development of a bullous, necrotic lesion with
eschar. The bite of Loxosceles laeta (the brown recluse spider) may resemble the cutaneous lesion of
anthrax, but it is very painful (Item C13D). Also, symptoms develop shortly after the bite and progress
rapidly within 24 hours. Francisella tularensis is the agent that causes tularemia. Signs and symptoms
develop within 3 to 5 days of exposure and include the abrupt onset of fever, chills, headache, malaise,
and fatigue as well as the development of a progressively enlarging, tender, localized lymphadenopathy
and a red, painful papule (Item C13E) in a region draining into the involved lymph nodes. The signs and
symptoms of Yersinia pestis (plague) develop abruptly and include fever; chills; weakness; headache;
and extremely tender, rapidly enlarging swelling of the lymph nodes of the groin, axilla, or neck.
References:
American Academy of Pediatrics. Anthrax. In: Pickering LK, Baker CJ, Long SS, McMillan JA, eds. Red
Book: 2006 Report of the Committee on Infectious Diseases. 27th ed. Elk Grove Village, Ill: American
Academy of Pediatrics; 2006:208-211
Butler T, Dennis DT. Yersinia species, including plague. In: Mandell GL, Bennett JE, Dolin R, eds.
Mandell, Douglas and Bennett's Principles and Practice of Infectious Diseases. 6th ed. New York, NY:
Elsevier Churchill Livingstone; 2005:2691-2700
Inglesby TV, Henderson DA, Bartlett JG, et al. Anthrax as a biological weapon: medical and public
health management. JAMA. 1999;281:1735-1745. Available at:
http://jama.ama-assn.org/cgi/content/full/281/18/1735
King MD, Humphrey BJ, Wang YF, Kourbatova EV, Ray SM, Blumberg HM. Emergence of
community-acquired methicillin-resistant Staphylococcus aureus USA 300 clone as the predominant
cause of skin and soft-tissue infections. Ann Intern Med. 2006;144:309-317. Abstract available at:

Penn RL. Francisella tularensis (tularemia). In: Mandell GL, Bennett JE, Dolin R, eds. Mandell, Douglas
and Bennett's Principles and Practice of Infectious Diseases. 6th ed. New York, NY: Elsevier Churchill
Livingstone; 2005:2674-2685
Swanson DL, Vetter RS. Bites of brown recluse spiders and suspected necrotic arachnidism. N Engl J
Med. 2005;352:700-707. Extract available at: http://content.nejm.org/cgi/content/extract/352/7/700
page 43

page 44
Critique: 13
Scanning electron micrograph at magnification 6408X demonstrates spores of
Bacillus anthracis. The spores may surive in soil for decades. (Courtesy of
the Centers for Disease Control and Prevention, Public Health Image Library,
Laura Rose)

page 45
Critique: 13
The classic lesion of cutaneous anthrax is a black eschar with surrounding
swelling, erythema, and induration. The affected area is not painful. (Courtesy
of the Centers for Disease Control and Prevention, Public Health Image
Library)

page 46
Critique: 13
Initial lesions of staphylococcal skin infection may be small tender papules
that often are attributed to spider bites (yellow arrows). Frequently, lesions
enlarge and develop an overlying pustule (black arrow). (Courtesy of Bernard
Cohen, MD, DermAtlas; www.dermatlas.org)

page 47
Critique: 13
An eschar with surrounding painful erythema and swelling is observed
following the bite of a brown recluse spider. (Courtesy of M. Smith)

page 48
Critique: 13
An ulcerated papule may appear at the site of inoculation of Francisella
tularensis. (Courtesy of the Centers for Disease Control and Prevention,
Public Health Image Library, Dr. Thomas F. Sellers)

Question: 14
A 3-month-old infant who has a history of renal dysplasia associated with obstructive uropathy has
marked polyuria. He is breastfeeding and receiving supplemental cow milk-based formula. In an effort
to reduce the high urine output, you consider reducing the renal solute load by changing feedings from
the milk-based formula currently being used.
Of the following, the MOST appropriate change is to
page 49
A. a hydrolyzed formula containing medium-chain triglycerides
B. a more concentrated (24-kcal) milk-based formula
C. human milk exclusively
D. soy milk-based formula
E. whole cow milk

The infant described in the vignette has polyuria caused by a urinary concentrating defect. The
concentrating defect is the result of tubular damage due to the obstructive uropathy. The inability to
concentrate the urine causes the kidneys to create an "excessive" volume of urine to excrete the solute
load presented to them.
One strategy to reduce polyuria is to reduce the solute burden placed on the kidneys. Potential renal
solute load is affected by intake of protein, sodium, potassium, chloride, and phosphorus. The protein
and phosphorus content are the most important variables when comparing infant feeding regimens.
page 50
Human milk possesses a lower potential renal solute load than cow milk or cow milk-based
formulas. Accordingly, the most appropriate change in feeding for the infant in the vignette is to
recommend that the mother stop cow milk formula supplementation and exclusively breastfeed. If
human milk is not available, a "low-solute" cow milk-based formula can be used. A low
calcium-phosphorus formula has the next lowest potential renal solute load compared with human milk.
Cow milk, soy milk-based formula, hydrolyzed formula with medium-chain triglycerides, and 24-kcal
milk-based formula all have greater renal solute loads than human milk.
Renal solute load should also be considered in nephrogenic diabetes insipidus.
References:
Fiorino KN, Cox J. Nutrition and growth. In: Robertson J, Shilkofski N, eds. Harriet Lane Handbook: A
Manual for Pediatric House Officers. 17th ed. Philadelphia, Pa: Elsevier Mosby; 2005:525-608
Hall RT, Carroll RE. Infant feeding. Pediatr Rev. 2000;21:191-200. Available at:
Linshaw MA. Congenital nephrogenic diabetes insipidus. Pediatr Rev. 2007;28:372-380. Available at:
Ziegler EE, Fomon SJ. Potential renal solute load of infant formulas. J Nutr. 1989;119 (12
suppl):1785-1788. Available at: http://jn.nutrition.org/cgi/reprint/119/12_Suppl/1785

Question: 15
A mother brings in her 13-month-old daughter for evaluation because her girl developed a perioral rash
and "hives" on two occasions last week. One episode occurred while eating yogurt and another
happened immediately after eating a bagel with cream cheese. She states that her daughter has eaten
other foods such as eggs and bread without problems but is breastfeeding and never has been given
milk-based formulas or cow milk. The infant has been given rice milk, but she became fussy and seems
to prefer breastfeeding. The mother is concerned that her daughter may be allergic to milk but would
like to stop breastfeeding.
Of the following, the BEST advice is to recommend
page 51
A. a cow milk food challenge in the clinic
B. avoidance of milk, egg, soy, and wheat products
C. breastfeeding until the child is 3 years old
D. switching to an amino acid-based formula
E. switching to soy milk

Milk protein allergy is an immunoglobulin (Ig) E-mediated food reaction that affects 2% to 3% of infants
within the first postnatal year. Typical symptoms include urticaria, angioedema, atopic dermatitis, and
anaphylaxis. With IgE-mediated reactions, the quantity of milk required to result in a reaction often is
minimal (eg, milk touching the face, a taste of ice cream). Taking a detailed history about the specific
food(s) involved, timing of the onset of symptoms, and type of symptoms is important to distinguish
IgE-mediated reactions, as described for the child in the vignette, from other adverse milk reactions,
such as milk protein enterocolitis and lactose intolerance. Once an IgE-mediated food allergy is
suspected, the clinician should consider allergy skin testing or serum IgE testing for the suspected food.
page 52
While awaiting results from either blood testing or allergy consultation for skin testing, the first
reasonable action is to switch to a soy-based formula. Approximately 10% to 15% of infants and
children who have IgE-mediated milk protein allergies may not tolerate soy formula, but this risk applies
to infants younger than 6 months of age. For infants older than 6 months, the risk is closer to 5%.
Nonetheless, the initial soy formula trial should be performed in the clinic. Other acceptable formula
options in this scenario include an extensively hydrolyzed or an amino acid-based formula, although the
unpleasant taste and significantly higher cost can be limiting for many families. Also, because almost all
affected infants can be fed successfully with a soy or extensively hydrolyzed formula, switching initially
to an amino acid-based formula is not required.
Food challenges often are used to assess adverse food reactions, but they generally are reserved
for foods that are unlikely allergens or if the clinical history is inconsistent or vague (eg, a patient who
eats a particular food and does not always have a reaction). Food challenges may result in anaphylaxis
and generally are avoided when the history and testing results support an IgE-mediated reaction.
Infants who have a specific food allergy sometimes are placed incorrectly on restricted diets that
avoid multiple foods. Without a specific history of other adverse food reactions, avoidance of other
foods such as egg or wheat is not recommended. However, parents should be counseled that children
can develop other food allergies and should monitor their children during ingestion of other common
food allergens.
Breastfeeding until age 3 years old is an option that is not preferred by the mother in the vignette.
Although most IgE-mediated cow milk allergies resolve by 3 years of age, milk protein allergy can
persist past 5 years of age in up to 20% of affected children.
References:
American Academy of Pediatrics Committee on Nutrition. Soy protein-based formulas:
recommendations for use in infant feeding. Pediatrics. 1998;101:148-153. Available at:
Bhatia J, Greer F, and the Committee on Nutrition. The use of soy protein-based formulas in infant
feeding. Pediatrics. 2008;121:1062-1068. Available at:
Klemola T, Vanto T, Juntunen-Backman K, Kalimo K, Korpela R, Varjonen E. Allergy to soy formula and
to extensively hydrolyzed whey formula in infants with cow's milk allergy: a prospective, randomized
study with a follow-up to the age of 2 years. J Pediatr. 2002;140:219-224. Abstract available at:
http://www.ncbi.nlm.nih.gov/ pubmed/11865274
Saarinen KM, Pelkonen AS, Mäkelä MJ, Savilahti E. Clinical course and prognosis of cow's milk allergy
are dependent on milk-specific IgE status. J Allergy Clin Immunol. 2005;116:869-875. Abstract

Sampson HA, Leung DYM. Adverse reactions to foods. In: Kleigman RM, Behrman RE, Jenson HB,
Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier;
2007:986-989
page 53

Question: 16
A 16-year-old girl is brought to the emergency department after being found unresponsive in her
bedroom. Her parents report finding a note in which she wrote of "wanting to end the pain." In addition,
they found several empty, unlabeled pill vials on her dresser. On physical examination, the girl is
responsive only to painful stimuli. Her heart rate is 60 beats/min, respiratory rate is 16 breaths/min,
blood pressure is 90/60 mm Hg, and oxygen saturation is 92%. Her pupils are 3 mm, equal in size, and
sluggishly reactive. The remainder of findings on her physical examination are normal.
Of the following, the MOST important diagnostic test to obtain when evaluating this patient is a
page 54
A. carboxyhemoglobin concentration
B. complete blood count
C. serum acetaminophen concentration
D. serum ammonia concentration
E. serum osmolality

Treatment of a patient who has ingested an unknown substance or substances, such as the one
described in the vignette, should focus initially on stabilization of vital functions; treatment of the
patient's symptoms; and identification of agents that are potentially fatal, have delayed clinical toxicity,
or for which antidotal therapy is indicated. The evaluation should include a screening history to identify
circumstances surrounding the event, potential environmental exposures, available medications or
toxins, and previous medical or psychiatric history. The physical examination should focus on vital sign
abnormalities, pupillary size and reactivity, skin findings, and mental status. These components are
likely to yield the most useful clues to toxins that have identifiable symptom complexes (Item C16A).
Laboratory testing should assess the patient's acid/base status, oxygenation and ventilation, glucose
concentration, and anion gap. Qualitative urine drug testing may be obtained but has significant
limitations, including the small number of drugs tested (typically drugs of abuse) and screening
thresholds that may produce false-negative results. Therefore, the results of urine toxicologic screening
rarely affect treatment plans. Quantitative drug concentrations should be measured based on the
information gleaned from the initial history, physical examination, and screening laboratory testing,
although acetaminophen and salicylate concentrations should be measured for every patient who has
an unknown, mixed, or intentional ingestion. Acetaminophen is of particular concern because it causes
few initial symptoms, is a common agent in adolescent and adult intentional ingestions, and may
require antidotal therapy to prevent potential fatal liver damage. Abdominal radiographs may be
considered to examine the patient for radio-opaque substances (Item C16B).
A complete blood count is not likely to provide information leading to the identification of a toxin.
Measurement of serum ammonia may be indicated if acetaminophen is identified as the ingested agent
because toxicity can lead to hepatic damage. Carboxyhemoglobin should be measured in the patient
whose history is suggestive of carbon monoxide exposure. Increased serum osmolality may provide
indirect evidence of alcohol ingestion, although a quantitative serum test for alcohols is more useful in
this setting.
References:
Erikson TB, Thompson TM, Lu JJ. The approach to the patient with an unknown overdose. Emerg Med
Clin North Am. 2007;25:249-281. Abstract available at: http://www.ncbi.nlm.nih.gov/pubmed/17482020
Lavallee M, Olsson J Jr, Cheng TL. In brief: unknown poison. Pediatr Rev. 2004;25:370-371. Available
at: http://pedsinreview.aappublications.org/cgi/content/full/25/10/370
McKay CA Jr. Can the laboratory help me? Toxicology laboratory testing in the possibly poisoned
pediatric patient. Clin Pediatr Emerg Med. 2005;6:116-122
Valez LI, Shepherd JG, Goto CS. Approach to the child with occult toxic exposure. UpToDate Online
15.3. 2008. Available for subscription at:
http://www.utdol.com/utd/content/topic.do?topicKey=ped_tox/3023&selectedTitle=4~150&source=searc
h_result
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Critique: 16

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Critique: 16

Question: 17
You are following a 3-month-old infant who was born at 30 weeks’ gestation, underwent a distal ileal
resection for necrotizing enterocolitis at 2 weeks of age, and subsequently was placed on parenteral
nutrition for 2 months. The baby has residual cholestasis from the parenteral nutrition (total bilirubin, 5.0
mg/dL [85.5 mcmol/L]; direct bilirubin, 3.0 mg/dL [51.3 mcmol/L]). Currently, she is receiving a cow milk
protein hydrolysate formula concentrated to 24 kcal/oz (0.8 kcal/mL). You are considering adding a
dietary supplement to increase the caloric density of the formula.
Of the following, the supplement that is the MOST likely to be tolerated and cause less diarrhea in this
infant is
page 58
A. flaxseed oil
B. medium-chain triglyceride oil
C. olive oil
D. omega-3 polyunsaturated fatty acid (fish oil)
E. soybean oil

Critique: 17 Preferred Response: B
Infants who have chronic illnesses may have specialized nutritional requirements and often do not
tolerate the standard 20-kcal/oz formula given to healthy term infants. For example, children who have
some forms of congenital heart disease or renal disease may require a more concentrated formula
because the standard formula may lead to volume overload. Children who have intestinal disease or
malabsorption, such as the child described in the vignette, also may require a more concentrated
formula to decrease the likelihood of feeding intolerance or diarrhea.
page 59
Formula may be concentrated by increasing the concentration of protein, carbohydrate, or fat.
Perhaps the easiest method of increasing the caloric density of a formula is to mix more powder with
the same amount of water. For example, four scoops of most commercially available formulas mixed
with 8 oz of water yields standard 0.67-kcal/mL (20-kcal/oz) formula, but mixing five scoops in 8 oz
results in 0.83-kcal/mL (25-kcal/oz) formula. However, exceeding 25-kcal/oz formula by increasing the
amount of powder may yield too high a concentration of protein, which could result in an excessive
renal solute load. For this reason, carbohydrate and fat supplements are available to concentrate infant
and toddler feedings further. The most common adverse effect of carbohydrate supplements is
diarrhea, and lipid supplements may cause either diarrhea or delayed gastric emptying. For these
reasons, caution is recommended when increasing the caloric density of a formula, especially when the
caloric density is increased to greater than 1 kcal/mL (30 kcal/oz).
Because the patient in the vignette has had an ileal resection and cholestasis, the best fat
supplement for him is oil composed of medium-chain triglycerides (MCT oil). MCT oil can be absorbed
directly across the enterocyte and does not require intraluminal digestion by bile acids. In contrast, soy,
olive, flaxseed, and fish oils are long-chain fatty acids that require bile acids for digestion and might
cause diarrhea in a child who has cholestasis and ileal resection.
References:
Courtney E, Grunko A, McCarthy T. Enteral nutrition. In: Hendricks KM, Duggan C. Manual of Pediatric
Nutrition. 4th ed. Hamilton, Ontario, Canada: BC Decker; 2005:252-316
Suchy FJ. Neonatal cholestasis. Pediatr Rev. 2004;25:388-396. Available at:

Question: 18
You have admitted a 750-g male infant to the neonatal intensive care unit (NICU) for treatment of
respiratory distress and presumed sepsis. The Apgar scores were 1, 5, and 7 at 1, 5, and 10 minutes,
respectively. The infant received one dose of exogenous surfactant in the delivery room. In the NICU,
the infant is being cared for on a radiant warmer. At 4 hours after birth, physical examination reveals a
temperature of 97.0°F (36.1°C), heart rate of 180 beats/min, respiratory rate of 40 breaths/min (assisted
breaths on the ventilator), blood pressure of 45/27 mm Hg, mean arterial blood pressure of 30 mm Hg,
and pulse oximetry of 92%. The infant is receiving synchronized intermittent mechanical ventilation with
a peak inflation pressure of 18 cm H2O over a positive end-expiratory pressure of 4 cm H2O at a rate of
40 breaths/min and an FiO2 of 0.40. Umbilical catheters are present in the umbilical artery and vein. On
physical examination, you note a soft, flat anterior fontanelle. You auscultate equal mechanical breath
sounds bilaterally over the chest and note minimal subcostal retractions. The skin is thin and somewhat
moist, and many veins are visible through it. The ears are flattened against the cranium and lack any
cartilage or recoil. There is a small phallus and an empty scrotum. The infant is laying on the warmer
with legs and arms extended. The neuromotor tone is decreased, and the infant does not appear to be
very active, but he does respond to tactile stimuli with movement of the arms and legs in seemingly
random and purposeless activity.
Of the following, the MOST important next step is to
page 60
A. administer another dose of exogenous surfactant
B. consult the urologist for cryptorchidism
C. increase the inspired oxygen concentration
D. move the infant into an isolette incubator
E. obtain head ultrasonography to evaluate for any hemorrhage

Critique: 18 Preferred Response: D
The extremely low gestational-age newborn (ELGAN) whose birthweight is less than 1,000 g may
present with physical examination findings indicative of marked physical and neurodevelopmental
immaturity. These findings have been studied and correlated with gestational age in scoring systems
such as those published by Dubowitz in 1980 and Ballard in 1979 and (revised) 1991. Even the best
efforts to estimate the gestational age of very low-birthweight and immature infants at dates less than
28 completed weeks of gestation by maternal last menstrual period and obstetric ultrasonography may
be imprecise and tend to overestimate maturity (gestational age) by 2 weeks. Nevertheless, the thin,
moist, transparent skin; flattened thin ears without cartilage or recoil; and small phallus and empty
scrotum described for the infant in the vignette indicate a degree of physical immaturity consistent with
28 weeks' gestation or less. Similarly, the low neuromotor tone, absence of flexed posture, relative
inactivity, and random purposeless flailing of extremities with tactile stimulation indicate significant
neurologic immaturity.
Moving the infant into an isolette incubator is an important next step in the care of this ELGAN. The
absolute benefit of using a radiant warmer bed (access to the infant to conduct early examinations,
admission nursing care, and procedures such as placement of umbilical catheters) is eclipsed by its
associated increased ambient convection, evaporative heat loss, and transcutaneous water loss
compared with the contained, convectively heated, and humidified environment of the isolette. The
isolette environment still allows access, visibility, and treatment with phototherapy, but with less
insensible water loss or variability in patient temperature.
This ELGAN is being treated for respiratory distress syndrome and has had a good response to
exogenous surfactant administration, oxygen, and assisted ventilation. At 4 hours of postnatal age, it is
too early to administer a second dose of surfactant. Developmentally cryptorchid testes may yet
descend into the scrotal sac in coming weeks. An oxygen saturation of 92% is good for this infant, and
increasing the inspired oxygen concentration may be harmful, contributing to oxidative injury of
pulmonary tissues or retinopathy of prematurity. Cranial ultrasonography is indicated in this sick and
preterm infant, but without clinical indications of hemorrhage, shock, and seizure or encephalopathy,
such a study is performed best at 3 to 7 days of postnatal life.
References:
Donovan EF, Tyson JE, Ehrenkranz RA, et al. Inaccuracy of Ballard scores before 28 weeks' gestation.
National Institute of Child Health and Human Development Neonatal Research Network. J Pediatr.
1999;135:147-152. Abstract available at: http://www.ncbi.nlm.nih.gov/pubmed/10431107
Marín GMA, Martín Moreiras J, Llitera Fleixas G, et al. Assessment of the new Ballard score to estimate
gestational age [in Spanish]. An Pediatr (Barc). 2006;64:140-145. English abstract available at:
Sedin G. The thermal environment of the newborn infant. In: Martin RJ, Fanaroff AA, Walsh MC, eds.
Fanaroff and Martin's Neonatal-Perinatal Medicine. 8th ed. Philadelphia, Pa: Mosby Elsevier;
2006:585-596
Thilo EH, Rosenberg AA. The newborn infant. In: Hay WW Jr, Levin MJ, Sondheimer JM, Deterding
RR, eds. Current Pediatric Diagnosis & Treatment. 18th ed. New York, NY: The McGraw-Hill
Companies, Inc; 2007:chap 1
page 61

Question: 19
You are called to the newborn nursery to evaluate a 1-day-old girl whose hands and feet are blue. She
was born at term via a cesarean section, and there were no complications. Apgar scores were 9 at both
1 and 5 minutes. Her respiratory rate is 40 breaths/min, heart rate is 140 beats/min, and blood pressure
is normal. Pulse oximetry is 98% on room air. Her lungs are clear, and there is no murmur. Her lips are
pink, but her hands and feet are cyanotic (Item Q19), and capillary refill is less than 2 seconds.
Of the following, the MOST likely cause of her peripheral cyanosis is
page 62
A. cold environment
B. polycythemia
C. retained fetal lung fluid
D. sepsis
E. transposition of the great arteries

page 63
Question: 19
Cyanosis of the feet, as exhibited by the infant in the vignette. (Courtesy of the
Media Lab at Doernbecher)

Cyanosis is a common finding in newborns. The first step in the evaluation of an infant who exhibits
cyanosis is to determine whether it is central or peripheral (acrocyanosis). The infant described in the
vignette has clinical features suggestive of acrocyanosis, a bluish discoloration of the hands and feet
(Item C19A) in response to vasomotor instability or cold environment. In this condition, the lips and
mucous membranes are spared, although the perioral area may be affected. The extremities may be
cool to touch. Acrocyanosis is believed to be due to vasoconstriction of small arterioles and resolves in
the first few postnatal months. Infants who have acrocyanosis require no further evaluation; parental
reassurance is all that is needed.
Central cyanosis is the bluish discoloration of the tissues best observed in the lips, tongue, mucous
membranes, and occasionally nail beds (Item C19B). It occurs when the concentration of deoxygenated
(reduced) hemoglobin exceeds 4.0 to 6.0 g/dL (40.0 to 60.0 g/L) within the capillary bed. In an individual
who has normal hemoglobin, cyanosis usually becomes apparent when the oxygen saturation drops
below 75%-80%. Causes of central cyanosis in the neonatal period typically are related to cyanotic
heart disease, such as transposition of the great arteries, or respiratory disease, such as pneumonia
and retained fetal lung fluid (transient tachypnea of the newborn). The absence of central cyanosis, a
cardiac murmur, and respiratory distress for the infant in the vignette makes these diagnoses less likely
than acrocyanosis of infancy.
Polycythemia, defined as a venous hematocrit of at least 65% (0.65), causes a deep reddish-purple
discoloration of the skin and mucous membranes. Infants may be otherwise asymptomatic or may
exhibit lethargy, anorexia, or respiratory distress. Polycythemia does not cause either peripheral or
central cyanosis per se, but it does affect the percent saturation at which cyanosis becomes clinically
apparent. Cyanosis in infants who have polycythemia occurs at higher oxygen saturations than in those
who have anemia. For example, if an infant has a hemoglobin of 24.0 g/dL (240.0 g/L), he is likely to
appear cyanotic when his oxygen saturation reaches 87%. In an infant who has a hemoglobin of 12.0
g/dL (120.0 g/L), cyanosis may not be seen until the oxygen saturation falls to 75%. Newborns who
have sepsis may develop cyanosis as a component of multisystem involvement, but other signs, such
as respiratory distress, poor peripheral perfusion, lethargy, or poor feeding, also are evident.
References:
Bernstein D. Evaluation of the cardiovascular system: history and physical examination. In: Kliegman
RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia,
Pa: Saunders Elsevier; 2007:1857-1863
Sasidharan P. An approach to diagnosis and management of cyanosis and tachypnea in term infants.
Pediatr Clin North Am. 2004;51:999-1021. Abstract available at:
page 64

page 65
Critique: 19
Acrocyanosis is a blue discoloration of the hands and feet. (Courtesy of the
Media Lab at Doernbecher)

page 66
Critique: 19
Central cyanosis, as exhibited by this infant who has tetralogy of Fallot, is
observed best in highly vascularized areas, such as the lips, tongue, mucous
membranes, and nail beds. (Courtesy of M. Rimsza)

Question: 20
A frustrated mother requests referral of her 15-month-old child to an allergy and asthma specialist
because the boy never seems to have stopped coughing and wheezing over the 6 months of the past
respiratory virus season. During the history taking, the mother states that the baby only occasionally is
exposed to wood smoke at the family’s barbecue restaurant and to cosmetic chemicals used at the
grandmother’s hair salon. Both the father and grandfather smoke cigarettes in the home.
Of the following, the environmental exposure that is MOST likely to be causing the child’s respiratory
symptoms is exposure to
page 67
A. cigarette smoke
B. cleaning fluids
C. dust mites
D. hairspray
E. wood smoke

The child described in the vignette may have multiple triggers for his wheezing exacerbations, although
tobacco smoke probably is the one to which he is exposed most often that should be diminished.
Well-known tobacco toxins include nicotine, carbon monoxide, formaldehyde, hydrogen cyanide, sulfur
dioxide, nitrogen oxide, ammonia, polycyclic aromatic hydrocarbons, and the nitrosamines. These
substances produce both irritant and immunologic effects on the respiratory tract. It is important to note
that smoking cessation is difficult, and most pediatricians have little training in the process. However,
there is evidence that a brief discussion of smoking cessation in the context of medical visits is
effective.
Wood smoke is another significant irritant to the respiratory tract; in addition to chemical irritants,
wood smoke contains particulate matter. Assuming that the family's restaurant kitchen meets current
standards for air filtration/exhaust, the child's exposure should be minimal. However, outdoor barbecue
pits that discharge smoke directly into the environment should be avoided.
Exposure to cooking spray/oils at the restaurant and cosmetic chemicals such as hairspray at the
salon also should be avoided, although the use of volatile organic compounds, including
chlorofluorocarbons in hairspray, permanent wave solution, cleaning solutions, and cooking sprays, has
decreased sharply since passage of the Clean Air Act and other Environmental Protection Agency
measures in the 1990s. Material Safety Data Sheets for most hairsprays, as well as other cosmetics
and cleaning fluids, reveal little inhalation toxicity, except in the case of prolonged exposure under
improper ventilation.
Although dust mite exposure may contribute to asthma exacerbation, there is no evidence that
environmental control can reduce the concentration of mites or exacerbations related to them. Finally,
serial respiratory virus infections themselves may contribute significantly to this child's history of
wheezing and cough.
The child in the vignette may benefit from therapeutic advances in asthma management such as
those contained in the National Heart, Lung and Blood Institute Guidelines for asthma, including
attention to number of symptomatic days, use of inhaled corticosteroids, and use of a metered dose
inhaler with spacer for proper delivery of medication, which may be more effective than nebulization in
older infants and children.
References:
Brunnhuber K, Cummings KM, Feit S, Sherman S, Woodcock J.Putting evidence into practice: smoking
cessation. BMJ Clinical Evidence. 2007. Available for subscription at:
http://clinicalevidence.bmj.com/ceweb/resources/index.jsp
Kum-Nji P, Meloy L, Herrod HG. Environmental tobacco smoke exposure: prevalence and mechanisms
of causation of infections in children. Pediatrics. 2006;117:5:1745-1754. Available at:
Roseby R, Waters E, Polnay A, Campbell R, Webster P, Spencer N. Family and carer smoking control
programmes for reducing children's exposure to environmental tobacco smoke. Cochrane Database
Syst Rev. 2003;3:CD001746. Available at: http://www.cochrane.org/reviews/en/ab001746.html
Stein RT, Holberg CJ, Sherrill D, et al. Influence of parental smoking on respiratory symptoms during
the first decade of life: The Tucson Children's Respiratory Study. Am J Epidemiol. 1999;149:1030-1037.
Available at: http://aje.oxfordjournals.org/cgi/reprint/149/11/1030
page 68

U.S. Environmental Protection Agency. Health effects of wood smoke. Available at:
http://www.epa.gov/woodstoves/healtheffects.html
U.S. Environmental Protection Agency. National volatile organic compound emission standards for
consumer products. Available at:
http://www.epa.gov/fedrgstr/EPA-AIR/1998/September/Day-11/a22660.htm
page 69

Question: 21
You are evaluating a newborn 6 hours after his birth. Labor and delivery were uncomplicated, but
amniocentesis performed during the pregnancy revealed trisomy 21. Fetal echocardiography at 20
weeks’ gestation showed normal findings. The infant currently is sleeping and is well-perfused, with a
heart rate of 140 beats/min and no audible murmurs. His physical features are consistent with Down
syndrome.
Of the following, the MOST appropriate diagnostic study to perform is
page 70
A. barium swallow
B. cervical spine radiography
C. echocardiography
D. head ultrasonography
E. radiography of the abdomen

Congenital heart defects (CHDs) are the most common of the congenital anomalies, occurring with an
incidence of approximately 5 to 8 per 1,000 live births (0.5% to 0.8%). The incidence of CHD is greater
in stillbirths and there is an increased incidence of CHD in those who have aneuploidy. It is believed by
some that the abnormal chromosomal composition rather than the cardiac abnormality is responsible
for the fetal demise of those who have CHDs. The strong association between chromosomal
abnormality and CHD has been shown in a number of studies that focus on identification of fetal cardiac
abnormality. A number of well-defined chromosomal anomalies are associated with CHD (Item C21).
page 71
Early and accurate diagnosis of CHD is important in counseling parents of children in whom a
chromosomal abnormality or syndrome is suspected. Such diagnoses may have significant effects on
the health and well-being of the newborns because some CHDs may require ductal patency for
perfusion of either the systemic or pulmonary circulation. Therefore, echocardiography now is
considered an important component of the routine health supervision of infants who have Down
syndrome and other syndromes predisposing to structural heart defects.
Although results of fetal echocardiography for the infant in the vignette were interpreted as normal,
not all CHDs can be diagnosed routinely with fetal echocardiography because of the shunting pathways
of the fetal circulation. For example, persistent patency of the ductus arteriosus and secundum atrial
septal defects are diagnosed postnatally. Small ventricular septal defects frequently are not seen during
fetal echocardiography because the pressure in the right and left ventricles are equal due to the ductus
arteriosus, resulting in minimal flow across the defect prenatally.
Given the strong association between Down syndrome and CHD, echocardiography should be
performed in the newborn described in the vignette. Although children born with Down syndrome have
an increased incidence of duodenal atresia and other types of gastrointestinal obstruction, a barium
swallow is not an appropriate initial test for an asymptomatic newborn. Cervical radiography, beginning
at age 3 years, is important because of the risk of atlantoaxial (C1-C2) subluxation. There is no
indication for routine head ultrasonography or abdominal radiography in an otherwise asymptomatic
newborn who has Down syndrome.
References:
Committee on Genetics. Health supervision for children with Down syndrome. Pediatrics.
2001;107:442-449. Available at: http://pediatrics.aappublications.org/cgi/content/full/107/2/442
Silberbach M, Hannon D. Presentation of congenital heart disease in the neonate and young infant.
Pediatr Rev. 2007;28:123-131. Available at:
Tennstedt C, Chaoui R, Körner H, Dietel M. Spectrum of congenital heart defects and extracardiac
malformations associated with chromosomal abnormalities: results of a seven year necropsy study.
Heart. 1999;82:34-39. Abstract available at: http://www.ncbi.nlm.nih.gov/pubmed/10377306

page 72
Critique: 21

Question: 22
A 4-year-old boy presents with headache and difficulty walking. On physical examination, he is afebrile,
all growth parameters are within normal limits, and his mentation appears normal. The optic discs are
clearly visible and appear normal. He has normal eye position in primary gaze but cannot abduct his
right eye fully. He has normal tone, strength, and reflexes in his upper limbs, but has bilateral
hyperreflexia at the knees and ankle clonus. On gait examination, he toe-walks.
Of the following, the MOST important next step is to obtain
page 73
A. computed tomography scan of the head
B. electromyography/nerve conduction studies of the legs
C. lumbar puncture
D. magnetic resonance imaging of the thoracolumbar spine
E. visual evoked potentials

The boy described in the vignette presents with a very concerning constellation of symptoms and signs
requiring urgent evaluation of the central nervous system. The first step in the diagnostic process is to
localize the problem to the proper level of the nervous system: brain, brainstem/cerebellum, spinal cord,
nerve, junction, or muscle. Such a determination not only allows for urgent appropriate diagnosis and
treatment but also reduces unnecessary discomfort, risks, and costs of inappropriate diagnostic testing.
Consultation with a neurologist can be useful before ordering testing. Headache, gait disturbance
(toe-walking), and acquired ocular misalignment (right eye cannot move to the right) localizes the
problem to the central nervous system and raises concerns for both hydrocephalus and a brainstem
lesion.
page 74
Computed tomography (CT) scan of the head is the preferred neuroimaging technique for this
patient. Although brain magnetic resonance imaging (MRI) can document the brainstem/posterior fossa
better, it may not be readily available. Moreover, a head CT scan in the emergency department is
adequate to rule out hydrocephalus that requires emergent neurosurgical consultation. Unfortunately, a
common cause for hydrocephalus in a child of this age is a brainstem or cerebellar neoplasm such as
an astrocytoma, glioma, medulloblastoma, or ependymoma. When these tumors enlarge in the
posterior fossa, they can obstruct the flow of cerebrospinal fluid and cause acute hydrocephalus, which
is a neurosurgical emergency.
Primary headache disorders such as migraine do not often present before the age of 6 years and
are not accompanied by the neurologic findings described in the vignette. Toe-walking is a nonspecific
finding that can occur in the context of relatively benign delayed development, although if this
represents a change for a child, an upper motor neuron (brain/spinal cord) lesion must be ruled out. The
ankle clonus described for the boy in the vignette mandates this approach. Similarly, inability to abduct
one eye can be congenital, but if this is a new finding, a brain or brainstem lesion must be ruled out. In
this case, headache and the oculomotor findings make a brain or brainstem lesion likely.
Gait impairment and hyperreflexia only in the legs can result from hydrocephalus or can localize to
the mid- to lower spinal cord. A spinal cord lesion would not explain the headache, and bilateral motor
findings without sensory, bowel, or bladder involvement are uncommon for a spinal cord lesion.
Therefore, MRI of the spine is not needed. Similarly, the hyperreflexia is not evidence of a nerve or
muscle problem, obviating the need for electromyography and nerve conduction studies. Lumbar
puncture is therapeutic for headache due to pseudotumor cerebri, which could present with this
constellation of symptoms, but this degree of gait abnormality would be uncommon in pseudotumor,
and the presence of true hydrocephalus or an intracranial mass must be excluded with a head CT or
brain MRI prior to lumbar puncture. Visual evoked potentials occasionally are used to determine
whether the axons from eye to occipital cortex function normally, but such a test generally is performed
when demyelinating disorders are suspected.
References:
Avellino AM. Hydrocephalus. In: Singer HS, Kossoff EH, Hartman AL, Crawford TO, eds. Treatment of
Pediatric Neurologic Disorders. Boca Raton, Fla: Taylor & Francis; 2005:25-36
Garton HJ, Piatt JH Jr. Hydrocephalus. Pediatr Clin North Am. 2004;51:305-325. Abstract available at:
Kestle JR. Pediatric hydrocephalus: current management. Neurol Clin. 2003;21:883-895. Abstract

Kuttesch J Jr, Ater JL. Brain tumors in childhood. In: Behrman RE, Kliegman RM, Jenson HB, Stanton
BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:2128-2136
Piatt JH Jr. Recognizing neurosurgical conditions in the pediatrician's office. Pediatr Clin North Am.
2004;51:237-270. Abstract available at: http://www.ncbi.nlm.nih.gov/pubmed/15062671
page 75

Question: 23
Parents who are new to your area bring in their 3-year-old daughter for evaluation because they are
concerned about her delayed speech. They say that she uses about 50 single words. The girl has had
tetralogy of Fallot repaired surgically and recurrent upper respiratory tract infections with otitis media,
for which tympanostomy tubes have been placed. Findings on physical examination include
microcephaly, underfolded pinnae, a broad nasal bridge, cleft uvula, and a small chin. In addition, the
child’s speech has a hypernasal quality. The family history is negative for birth defects and
developmental delays.
Of the following, the contiguous gene deletion syndrome that BEST fits this child’s features is
page 76
A. Angelman
B. Beckwith-Wiedemann
C. 4p-
D. Prader-Willi
E. 22q11

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