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Flashcards in Cystic fibrosis Deck (12):
1

Most common recessive genetic disorder in white population

Cystic fibrosis

2

Pathophysiology

1. Mutation in CF transmenbrane regulator->chloride channel

2. +Chloride excretion, +Na and water reabsorption= thick mucus secretion

3. Lung impaired, exocrine pancreas impaired, infertility in men when vas deferens absent, ++salt in sweat, meconium ileus

4. 1 in 2500 affected, 1 in 25 carrier

5. Most common mutation is delatF508

3

Presentation

1. 90% are detected at neonatal screening->Day 2-4 test serum trypsinogen->genetic testing, sweat test

2. Meconium ileus (10%)

3. Malabsorption

4. Chronic respiratory infections

5. Failure to thrive

6. Some may have atypical presentations

4

Common problems and management

1. Chest infections

Pseudomonas, Bulkholderia cepacia

Bronchodilators

Antibiotics

Steroids

Nebulised DNAse enzymes to break down mucus

2. Malabsorption

Fatty foods++, high calories

Pancreatic enzyme replacement

ADEK replacement

Advice from specialist dietician

3. Diabetes

25% IGTT

Optimisation of blood glucose

4. Salt loss

Salt replacement with careful monitoring

5. Liver disease->biliary cirrhosis

Ursodeoxycholic acid

Pseudobowel obstruction

6. Subfertility

Absence of vas deferens

Carrier testing in partners

CV/Amniocentesis for antenatal diagnosis recommended

5

Diagnosis

1. Newborn screening->Immunoreactive serum trypsin levels

2. Better prognosis if detected before syptoms

3. Gene testing

4. Sweat test

6

Prognosis

1. Significant improvement in treatment over last 25 years, >50% will live >38 years

2. Lung function test best measure of disease progressioon

3. Heart-lung transplant offered to those with end stage respiratory disease->some survive >15 years beyond their transplant

7

History

1. May be family history

2. FTT w/ ravenous appetite

3. Cough and wheeze

4. Recurrent chest infections

5. Recurrent sinusitis

6. Bulky, pale, offensive smelling stools

7. Fall in lung function and weight loss may indicate onset of CF-related diabetes

8

Examination

1. Finger clubbing

2. Growth, malnutrition, poor weight gain

3. Delayed puberty->tanner staging

4. Nasal polyps

5. Chest deformity->hyperinflation

6. Crackles

7. Firm enlarged liver, splenomegaly

8. Subcutaneous vascular access

9. Gastrotemy tube may be present

9

Features of recurrent respiratory infection

1. Cough

2. Purulent sputum

3. Pneumonia

4. Chronic pseudomonas

5. Bronchiectasis

6. Chest deformity

7. Eventual respiratory failure

10

Features of poor growth

1. Requires 40% extra energy intake

2. Poor weight gain

3. Short stature

4. Normal growth acheivbable with pancreatic enzyme replacement and aggressive treatment of chest infections

5. Malabsorption

11

Gastrointestinal effects

1. Pancreatic insufficiency

2. Poor fat absorption

3. Steatorrhea

4. Distended abdomen

5. Rectal prolapse

6. Distal intestinal obstruction syndrome->can mimic appendicitis

7. Need pancreatic enzymes with food

8. Diabetes

9. Meconium ileus

12

Appearance on chest radiograph

1. Gross overinflation

2. Hilar enlargement

3. Ring shadows due to bronchial wall thickening

4. Bronchiectatic changes

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