2. Cystic fibrosis
Is a disease of the exocrine glands that
causes viscid secretions. The gastrointestinal
and respiratory systems are the most
commonly and most severely affected.
It is inherited as autosomal recessive trait by
a gene located on chromosome 7. The most
common mutation is an absence of three
base pairs that encode for the amino acid
phenylalanine(∆ F 508).
3. Cystic fibrosis
The abnormal protein that the gene encodes
is the chloride channel Cystic Fibrosis
Transmembrane Regulator (CFTR).
In the cell membrane these channels are
blocked so that chloride ion is trapped inside
the cell and draws sodium ions and water
into the cell resulting in dehydration of mucus
secretions and abnormal ion and water
environment surrounding the cell.
4. Cystic fibrosis
Clinical features
Clinical presentation of CF vary considerably,
Neonatal presentation may be with
1.muconium ileus.
2. prolonged jaundice.
3.part of prenatal workup or neonatal screening.
The most common manifestations are
Respiratory: repeated chest infections with
staph.aureus, pseudomonas auerogenosa and
H. infleunzae leading to progressive lung disease with
5. Cystic fibrosis
Clinical features
Bronchiaectasis, clubbing, abscess formation,
hemoptysis and eventually Cor pulmonale.
Gastrointestinal : Malabsorption of fat and protein
due to pancreatic insufficiency and abnormal mucus
gland secretions in the GI tract occur in 90% of
patients, this results in fatty stools, fat soluble vitamin
deficiencies, failure to gain weight and retarded
growth. Rectal prolapse, biliary cirrhosis, and portal
hypertension may complicate the disease.
6. Cystic fibrosis
Clinical features
Metabolic: Frank diabetes occur in 2% of children
with CF. Salt depletion can occur as a result of hot
climate.
Arthropathy: Reduced joint mobility with pain occur
in 1-2% of children with CF.
Reproductive: Virtually all males are sterile and
females have reduced fertility.
Nasal: chronic sinusitis is seen in all patients and
nasal polyps occur in 5% of all patients.
7. Cystic fibrosis
Diagnosis
Diagnostic criteria for CF include:
Positive sweat test.
Typical pulmonary manifestations.
Typical gastrointestinal manifestations.
Positive family history.
The sweat test is positive if the chloride
concentration of sweat exceeds 60meq./L.
8. Cystic fibrosis
Diagnosis
DNA testing is available for the 150 common
CF mutations. The indications are:
If adequate amount of sweat for analysis
cannot be collected.
If sweat test results are borderline.
If sweat test results do not correlate with the
clinical symptoms.
For prenatal diagnosis.
9. Cystic fibrosis
Therapy
Treatment of respiratory problems:
A. Antibiotics
1. oral: antistaphylococcal
2. aerosolized aminoglycoside
3. Intravenous therapy for 10-21 days in cases of
pneumonia, aminoglycoside and semi synthetic
penicillin or a third generation cephalosporin.
B. Other drugs bronchodilators, mucolytics and
steroids can be used.
10. Cystic fibrosis
Therapy
C. Chest physiotherapy like breathing exercises,
postural drainage, and active cycles of breathing to
aid the clearance of viscid secretions.
Treatment of digestive problems
1. pancreatic enzymes before each meal.
2. high calorie, high protein diet.
3. vitamin supplementation specially fat soluble ones.
4. stool softener
5. Antacid and H2 receptor antagonists.
11. Cystic fibrosis
Therapy
Treatment of complications
like muconium ileus by surgery or muconium
ileus equivalent by acetylcysteine enemas or
pneumothorax by chest tube.