Urinary tract infections during pregnancy

1. Urinary tract infections
during pregnancy
Prof Aboubakr Elnashar
Benha University Hospital
Aboubakr Elnashar

2. Definitions
Urinary tract infection
An asymptomatic:
100,000 organisms/ml of urine
Symptomatic:
100 organisms/mL of urine with accompanying
pyuria (>7WBCs]/mL)
Diagnosis should be supported by a positive
culture, particularly with vague symptoms.
Risks:
pyelonephritis,
preterm birth, low birth weight,
increased perinatal mortality.
Aboubakr Elnashar

3. Asymptomatic bacteriuria
100,000 organisms/mL in 2 consecutive urine
samples in the absence of symptoms.
Pregnant: 2.5-11%
Nonpregnant: 3-8%
Aboubakr Elnashar

4. Acute cystitis
inflammation of the bladder
{bacterial or nonbacterial causes (eg, radiation or
viral infection)}.
1% of pregnant patients
Aboubakr Elnashar

5. Acute pyelonephritis
2% of all pregnancies.
2% during the 1st trimester
52% during the 2nd trimester
46% in the 3rd trimester.
Aboubakr Elnashar

6. Epidemiology
UTIs in women: 14 times more frequent than
in men.
1. The urethra is shorter
2. lower 1/3 of the urethra is continually
contaminated with pathogens from the vagina and
the rectum
3. Women tend not to empty their bladders as
completely as men do
4. Urogenital system is exposed to bacteria during
intercourse
Aboubakr Elnashar

7. Increase the frequency (UTIs) in pregnant
women.
1. Difficult hygiene due to a distended pregnant
belly
2. Immunocompromised
Aboubakr Elnashar

8. 3. Hormonal and mechanical changes:
urinary stasis and vesicoureteral reflux
urinary stasis {progesterone-induced ureteral
smooth muscle relaxation}
urinary retention {weight of the enlarging uterus}
Loss of ureteral tone combined with increased
urinary tract volume: urinary stasis: dilatation of the
ureters, renal pelvis, and calyces.
more common on right side (86% of cases)
more pronounced on right (15 mm vs 5 mm).
begin at10 w and worsens throughout pregnancy.
Aboubakr Elnashar

9. 4. Glycosuria and aminoaciduria
Glycosuria {impaired resorption by the collecting
tubule and loop of Henle of the 5% of the filtered
glucose, which escapes proximal convoluted
tubular resorption}.
Selective aminoaciduria {unknown} although its presence has been postulated to
affect the adherence of Escherichia coli to the urothelium.
Aboubakr Elnashar

10. Asymptomatic bacteriuria
Risk factors
5-fold poor patients
doubled in sickle cell trait.
Other risk factors
DM
Neurogenic bladder retention
History of vesicoureteral reflux
previous renal transplantation
history of previous UTIs
multiple pregnancy
prolonged hospitalization
Aboubakr Elnashar

11. Symptomatic UTI:
2.3%.
increases with maternal age.
Aboubakr Elnashar

12. Pathophysiology
Infections result from ascending colonization of
the urinary tract, primarily by existing
vaginal,
perineal, and
fecal flora.
Aboubakr Elnashar

13. Etiology
Infection
E coli : most common cause of UTI, 80-90%
originates from fecal flora colonizing the periurethral
area: ascending infection.
Other pathogens:
Klebsiella pneumoniae (5%)
Proteus mirabilis (5%)
Enterobacter species (3%)
Staphylococcus saprophyticus (2%)
Group B beta-hemolytic Streptococcus (GBS; 1%)
Proteus species (2%)
Aboubakr Elnashar

14. S saprophyticus, an aggressive organism: UUTI:
persistent or recurrent
Urea-splitting bacteria
Proteus, Klebsiella, Pseudomonas, and coagulase
negative Staphylococcus: alkalinize the urine:
stones.
Chlamydial infections
:sterile pyuria (30% of atypical pathogens).
Aboubakr Elnashar

15. GBS colonization
Intrapartum transmission: neonatal GBS
pneumonia, meningitis, sepsis, and death.
Guidelines
universal vaginal and rectal screening in all pregnant
women at 35-37 W rather than treatment based on
risk factors.
Aboubakr Elnashar

16. Preeclampsia
predisposed to UTI.
UTI
16.2% in normotensive
27.3% in mild PET
35.9% in severe PET
{underlying renal damage weakens patients’
systemic defense mechanisms against ascending
infection}.
Aboubakr Elnashar

17. Cesarean delivery
:UTI (2.7-fold),
confounded by bladder catheterization or PROM).
symptomatic UTI: 9.3%
asymptomatic bacteriuria: 7.6%.
Aboubakr Elnashar

18. Beta streptococci bacteriuria
Indicate higher colonization count than revealed by
vaginal or rectal culture.
 immediate treatment
intrapartum antibiotic prophylaxis
: preterm labor: controversial.
Aboubakr Elnashar

19. Complications
UTI during pregnancy is independently:
IUGR
Preeclampsia
preterm delivery
CS.
Asymptomatic bacteruria
acute cystitis (40%)
pyelonephritis (30%).
risk of preterm birth: 1.8-2.3
Acute cystitis
low birth weight and preterm delivery
Pyelonephritis: 15-50% of cases.
Aboubakr Elnashar

20. Untreated upper UTIs
low birth weight, prematurity, premature labor
hypertension, preeclampsia
maternal anemia, and
amnionitis.
Aboubakr Elnashar

21.  Other complications:
1. Perinephric cellulitis and abscess, Septic
shock (rare)
2. Renal dysfunction (usually transient, but as many
as 25% of pregnant women with pyelonephritis
have a decreased glomerular filtration rate)
3. Hematologic dysfunction (common but seldom of
clinical importance)
4. Pulmonary injury: 2% of women with severe
pyelonephritis
during pregnancy have evidence of pulmonary injury due to systemic inflammatory response syndrome
and respiratory insufficiency. Endotoxins that alter alveolar-capillary membrane permeability are
produced; subsequently, pulmonary edema and acute respiratory distress syndrome develop.
•
Aboubakr Elnashar

22. 5. Hypoxic fetal events {maternal complications of
infection that lead to hypoperfusion of the placenta}
6. PTL: increased infant morbidity and mortality
Aboubakr Elnashar

23. Diagnosis
I. History
 Cystitis
1. Dysuria
most significant symptom
2. Other symptoms:
Frequency
Urgency
suprapubic pain
hematuria in the absence of systemic symptoms.
The usual complaints of increased frequency, nocturia, and suprapubic pressure
are not particularly helpful, {most pregnant women experience these as a
result of increased pressure from the growing uterus, expanding blood
volume, increased glomerular filtration rate, and increased renal blood
flow.}
Aboubakr Elnashar

24. Pyelonephritis:
1. Fever (>38°C)
2. Shaking chills
3. Anorexia, nausea, and vomiting.
4. Right-side flank pain is more common than left-
side or bilateral flank pain.
5. Lower UTI symptoms: common but not
universal.
6. ±hypothermia (as low as 34°C).
Aboubakr Elnashar

25. II. Physical Examination
Pelvic examination:
recommended in all symptomatic patients
(with the exception 3rd trimester patients with
bleeding) to rule out vaginitis or cervicitis
Aboubakr Elnashar

26. Asymptomatic bacteriuria
No physical findings are typically present.
Symptoms may arise intermittently, only to be overlooked because of
lack of persistence or severity.
Cystitis
Tenderness.
Aboubakr Elnashar

27. Pyelonephritis
1. Fever (usually >38°C) an ill appearance.
2. Flank tenderness
on the right side in more than half of patients,
bilaterally in one fourth
on the left side in one fourth.
3. Assessment of the FHR
{maternal fever} FHR: elevated to more than 160
beats/min.
Aboubakr Elnashar

28. Investigations
Blood Studies
CBC
Serum electrolytes
Blood urea nitrogen (BUN)
Serum creatinine
Aboubakr Elnashar

29. Urine Studies
Urine specimen collection
All pregnant patients
urinalysis and culture (Screening)
in 1st prenatal visit or at 12-16w.
identify asymptomatic bacteriuria, as well as those
with other concerning findings such as glucosuria.
Midstream clean catch
With one hand, spread the labia
With the other hand, use a castile soap–moistened towelette to wipe the
urethral meatus downward toward the rectum, then discard the towelette
Void the initial portion of the bladder contents into the toilet
Catch the middle portion of the bladder contents in the sterile collection
container, while keeping the labia spread with the first hand
Aboubakr Elnashar

30. > 1 organism in a culture: contaminated
specimen.
The specimen should be sent for evaluation as soon as possible
{Specimens that are allowed to sit at room temperature may have falsely
elevated colony counts}. Refrigerate the specimen at 4°C if it cannot be
transported immediately.
Aboubakr Elnashar

31. Urine culture
Standard method for evaluating for UTI during
pregnancy.
Indications :
Recurrent UTI
Pyelonephritis
Failure to respond to initial treatment
History of recent instrumentation
Hospital admission
Aboubakr Elnashar

32. Positive culture
Two consecutive voided specimens with isolation of the
same bacterial strain, at a colony count of 100,000 colony-
forming units (CFUs) per milliliter or higher OR
A single catheterized specimen yielding a colony count of at
least 100 CFU/mL
Contamination
Counts lower than 100,000 CFU/mL, with 2 or more
organisms
Patients with pyelonephritis often have white blood cell
(WBC) casts.
Culture results can be used to identify specific organisms
and antibiotic sensitivities
Cultures yielding significant growths of mixed organisms
should prompt a search for underlying renal calculi.
Aboubakr Elnashar

33. Urinalysis
Positive results for nitrites, leukocyte esterase,
WBCs, RBCs, and protein: suggest UTI.
Bacteria found in the specimen can help with the
diagnosis.
Urinalysis:
Specificity (ability to identify negtive results): 97-100%
Sensitivity (ability to identify positive results).: 25-67%=false-positive rate is very high
1-2 bacteria in an unspun catheterized specimen
or >20 bacteria /HPF in spun urine correlate closely
with bacterial colony counts >100,000 CFU/mL on a
urine culture. Aboubakr Elnashar

34. Dipstick testing for nitrites & leukocyte esterase
in the evaluation of asymptomatic bacteriuria:
Sensitivity: 50% to 92% and
Specificity: 86% to 97%.
In the evaluation of symptomatic:
useful and inexpensive.
leukocyte esterase test may be unreliable in
patients with low-level pyuria (5-20 WBCs/HPF).
The addition of protein and blood increases the
sensitivity and specificity of the test in the
evaluation of UTI.
Aboubakr Elnashar

35. Nitrite dipstick testing
may be a reasonable and cost-effective screening
strategy for women who otherwise may not
undergo screening for bacteriuria, as is often the
case in developing countries.
Aboubakr Elnashar

36. Urine cytology:
useful adjunct in detecting UUTIs.
Clumping WBCs and WBC casts:
pyelonephritis.
RBC casts:
acute glomerulonephritis
Oval fat bodies and fatty casts:
Membranous glomerulonephritis.
Renal involvement:
proteinuria.
Nephrotic syndrome:
high proteinuria (>3.5 g/24 h), edema, hypercholesterolemia, and
hypoalbuminemia;
can be confused with preeclampsia.
Aboubakr Elnashar

37. Other tests
An antistreptolysin-O (ASO) titer:
greater than 200 Todd units: recent group A streptococcal
infection; however, as many as 20% of patients with acute
glomerulonephritis have ASO titers within the reference
range.
The sulfosalicylic acid (SSA) test:
measures urine turbidity when a small amount of aspirin is
added to the urine specimen.
A finding of +2 to +4 suggests bacteriuria.
Aboubakr Elnashar

38.  Renal Ultrasonography and limited
Intravenous Pyelography (IVP)
Indications
1. An anatomic abnormality or renal disease is
suspected
2. Patients with suspected pyelonephritis who are
not responsive to appropriate antibiotic therapy
after 48-72 h
3. Recurrent UTI or symptoms that suggest
nephrolithiasis, if the benefits of a definitive
diagnosis outweigh the minor risk of radiation
Aboubakr Elnashar

39. Renal US is often performed initially, but the
findings are often inconclusive.
A limited IVP (kidneys-ureters-bladder [KUB] with
a 30-min shot after contrast injection) can be
helpful in delineating the site of the obstruction.
Aboubakr Elnashar

40. The total dosage of ionizing radiation should not
exceed 3-5 cGy during the course of pregnancy.
Of particular concern is radiation delivered during
1st trimester, during organogenesis (especially days
11-56).
A limited IVP can deliver 0.4-1 cGy.
Radiation doses >5 cGy: increased likelihood of
benign and malignant tumors in the child after birth.
No patient should receive more than 10-14 cGy.
Centigray: a unit of absorbed radiation dose equal
to one hundredth of a gray, or 1 rad.
Aboubakr Elnashar

41. Urolithiasis
unique problem in pregnant women.
Diagnosis:
Pyelonephritis have many symptoms in common
(eg, hematuria, flank pain, shaking chills, anorexia).
usually not associated with fever, except in
patients with concomitant pyelonephritis.
Confusion about the diagnosis of urolithiasis,
pyelonephritis, or both is an indication for obtaining
imaging studies.
Aboubakr Elnashar

42. Treatment
initially conservative
{50-67% diagnosed during pregnancy pass
spontaneously}
Antibiotic
Hydration
Analgesics
(usually narcotics, which are class C agents in
pregnancy).
Anti-inflammatory {oligohydramnios, premature
closure of the patent ductus arteriosus, or both}
should be avoided if possible.
Aboubakr Elnashar

43.  If ultrasonography reveals a stone, ultrasound-
guided cystoscopic passage of a ureteral stent may
relieve ureteral colic.
In some cases (eg, pyonephrosis with an
obstructing stone), percutaneous nephrostomy can
be useful.
Cystoscopic extraction of a distal ureteral stone
(with fluoroscopic guidance) should be used
sparingly because of the risk of ionizing radiation to
the fetus.
Aboubakr Elnashar

44. Treatment
Bacteriuria and cystitis
1. Administration of appropriate antibiotics
2. Administration of fluid if the patient is
dehydrated
3. Admission if any indication of complicated UTI
exists
Aboubakr Elnashar

45. Behavioral methods
To ensure good hygiene and reduce bacterial contamination of the urethral
meatus: preventing inadequate treatment and recurrent infection.
1. Avoid baths
2. Wipe front-to-back after urinating or defecating
3. Wash hands before using the toilet
4. Use washcloths to clean the perineum
5. Use liquid soap to prevent colonization from bar soap
6. Clean the urethral meatus first when bathing
7. Changes in coital patterns (eg, position, frequency, postcoital antibiotics) can
offset recurrence in at-risk individuals.
Several non-pharmacological manoeuvres may help prevent recurrent infec-
tion in those women troubled by UTIs in pregnancy. These include:
Increasing fluid intake. This ensures frequent voiding and a high-volume dilute
urine, all of which reduce the risk of symptomatic infection Emptying the bladder
following sexual intercourse. This 'washes away' organisms massaged up the
urethra from the perineum into the bladder during coitus, before they have a
chance to replicate in urine within the bladder
Double voiding (to ensure no residual urine is left in the bladder following
micturition)
The perineum should be cleaned from 'front to back' following defaecation to
minimise the risk of bowel organisms colonising the urethra.
Aboubakr Elnashar

46. Aboubakr Elnashar

47. Antibiotic therapy
Oral antibiotics are the treatment of choice for
asymptomatic bacteriuria and cystitis.
William (2010)
Single-dose treatment
Amoxicillin 3 g
Ampicillin 2 g
Cephalosporin 2 g
Nitrofurantoin 200 mg
Trimethoprim-sulfamethoxazole 320/1600 mg
Aboubakr Elnashar

48. 3-day course
Amoxicillin 500 mg three times daily
Ampicillin 250 mg four times daily
Cephalosporin 250 mg four times daily
Ciprofloxacin 250 mg twice daily
Levofloxacin 250 mg daily
Nitrofurantoin 50 to 100 mg four times daily; 100 mg twice
daily
Trimethoprim-sulfamethoxazole 160/800 mg two times daily
Other
Nitrofurantoin 100 mg four times daily for 10 days
Nirofurantoin 100 mg twice daily fo 7 days
Nitrofurantoin 100 mg at bedtime for 10 days
Aboubakr Elnashar

49. Treatment failures
Nitrofurantoin 100 mg four times daily for 21 days
Suppression for bacterial persistence or
recurrence
Nitrofurantoin 100 mg at bedtime for remainder of
pregnancy
Aboubakr Elnashar

50. The resistance of E coli to ampicillin and
amoxicillin is 20-40%; accordingly, these agents
are no longer considered optimal for treatment of
UTIs caused by this organism.
Fosfomycin, a phosphonic acid derivative, is useful in the treatment of
uncomplicated UTIs caused by susceptible strains of E
coli and Enterococcusspecies.
Fosfomycin is a category B agent in pregnancy (ie, fetal risk is not
confirmed by human studies but has been shown in some animal
studies).
Aboubakr Elnashar

51. Although 1-, 3-, and 7-day antibiotic courses have
been evaluated, 10-14 days of treatment is usually
recommended to eradicate the offending bacteria.
Treatment for 3 days is sufficient for asymptomatic
bacteriuria. Regular urine cultures should be taken
following treatment to ensure eradication of the
organism. About 15% of women will have recurrent
bacteriuria during their pregnancy and require a
second course of antibiotics.
Antibiotics should be continued for 5-7 days in
cystitis
Cephalexin, trimethoprim-sulfamethoxazole, and
amoxicillin single dose is as effective as a 3- to 7-
day course of therapy, but the cure rate is only
70%. Aboubakr Elnashar

52. A test-for-cure urine culture should show negative
findings 1-2 w after therapy.
A nonnegative culture result is an indication for a
10- to 14-day course of a different antibiotic,
followed by suppressive therapy
(eg, nitrofurantoin 50 mg at bedtime) until 6 w
postpartum.
Aboubakr Elnashar

53. Acute Pyelonephritis
Hospitalization
Investigations and monitoring
Urine and blood cultures
CBC, serum creatinine, and electrolytes
Monitor vital signs frequently, urinary output,
consider indwelling catheter
Establish urinary output to 50 mL/hr with IVF
Chest radiograph if there is dyspnea or
tachypnea
Aboubakr Elnashar

54.  IV antibiotics
IV fluids
with caution. Patients with pyelonephritis can
become dehydrated {nausea and vomiting} and
need IV hydration. However, they are at high risk
for the development of pulmonary edema and
ARDS
Fever:
antipyretics (preferably, acetaminophen)
Nausea and vomiting:
antiemetics.
Most antiemetics can be used for adverse effects caused by antibiotics,
but doxylamine, Emetrol (Wellspring, Sarasota, FL; pregnancy class A),
dimenhydrinate, and metoclopramide (pregnancy class B) are preferred.
Aboubakr Elnashar

55. Follow up
Repeat hematology and chemistry studies in 48 h
Change to oral antimicrobials when afebrile
Discharge when afebrile 24 h, consider antibiotic
for 7 to 10 days
Repeat urine culture 1 to 2 weeks after antibiotic
completed
Aboubakr Elnashar

56. Risk of PTL must be evaluated and treated early in
the course of admission.
{Pyelonephritis places the patient at risk for
spontaneous abortion in early pregnancy and for
preterm labor after 24 w}.
Aboubakr Elnashar

57. Antibiotic selection
IV administration of cephalosporins or gentamicin.
Antibiotic selection should be based on urine
culture sensitivities, if known. Often, therapy must be
initiated on an empirical basis, before culture results
are available.
Institution-specific drug resistances should also be
considered before a treatment antibiotic is chosen.
E coli infection resistance to
Ampicillin: 28-39%.
Trimethoprim-sulfamethoxazole: 31%
First-generation cephalosporins: 9-19%.
Aboubakr Elnashar

58. Some antibiotics should not be used during
pregnancy:
 Tetracyclines (adverse effects on fetal teeth and
bones and congenital defects)
Chloramphenicol (gray syndrome)
Trimethoprim in the first trimester (facial defects
and cardiac abnormalities)
Sulfonamides (hemolytic anemia in mothers with
glucose-6-phosphate dehydrogenase [G6PD]
deficiency, jaundice, and kernicterus) in the third
trimester.
Aboubakr Elnashar

59. Fluoroquinolones:
are contraindicated in pregnancy.
Although in utero exposure is not an indication for
termination, fetal exposure to fluoroquinolones has
been associated with myelomeningocele,
hydrocephaly, hypospadias, maldescended testes,
inguinal hernia, bilateral hip dysplasia, and atrial
septal defects. That the anomalies seem not to
follow a particular pattern may be reassuring;
however, a causal relation cannot be excluded.
Aboubakr Elnashar

60. Nitrofurantoin
safe and effective; however, poor tissue penetration
has limited its use in pyelonephritis.
In the past, nitrofurantoin was completely avoided
in the third trimester because of hemolytic effects
on the newborn. Currently, restriction of this agent
is limited to the last several weeks of pregnancy.
Use during this period can cause hemolytic anemia
in the fetus or neonate as a consequence of their
immature erythrocyte enzyme systems (glutathione
instability).
Nitrofurantoin is also safe and effective for once-
daily prophylactic therapy during pregnancy.
Aboubakr Elnashar

61. Macrolides
not first-line agents for UTI in pregnancy.
However, they are well tolerated by mother and
fetus.
Aboubakr Elnashar

62. Surgical treatment
Rarely indicated, unless one of the pathologic
causes listed in the differential diagnoses is
suspected.
In patients with urethral or bladder diverticulum,
bladder stones, urethral syndrome, lower urinary
tract trauma, interstitial cystitis, or bladder cancer,
cystoscopy may aid in establishing the diagnosis.
A retrograde stent or a percutaneous
nephrostomy tube should be placed to relieve
ureteral colic or decompress an obstructed infected
collecting system. More invasive procedures, such
as ureteroscopic stone extraction,are rarely
indicated. Aboubakr Elnashar

63. Extracorporeal shock wave lithotripsy (ESWL) is
contraindicated in pregnancy.
In the rare patient for whom invasive surgical
therapy is indicated, the operation should be
planned for the second trimester. Surgical
intervention during the first trimester is associated
with miscarriage; surgery in the third trimester is
associated with preterm labor. Urgent surgical
intervention in the third trimester should coincide
with delivery of the fetus.
Aboubakr Elnashar

64. Conclusion
Urinary tract infection is more common in
pregnancy.
Asymptomatic bacteriuria should be treated
because there is a significant risk of acute
pyelonephritis.
Acute pyelonephritis increases the risk of premature
labour.
Acute pyelonephritis should be managed in hospital
with i.v, antibiotics.
Once antibiotic treatment has rendered the urine
sterile, regular MSU specimens are necessary to
exclude reinfection.
Aboubakr Elnashar

65. Amoxycillin and cephalosporins are appropriate
antibiotics for the treatment and prevention of UTI in
pregnancy.
Gentamicin may be required for severe or resistant
infections.
Investigations in cases of pyrexia and suspected
acute pyelonephritis should include blood cultures, a
full blood count, renal function and a renal US.
Aboubakr Elnashar

66. Thank you
Aboubakr Elnashar
Aboubakr Elnashar