Cystic fibrosis

Question 1

Cystic fibrosis presentation

Answer 1

Please examine this young man’s chest and comment on what you find.

Question 2

Clinical signs of Cystic fibrosis

Answer 2

• Inspection: small stature, clubbed, tachypnoeic, sputum pot (purulent++)
• Hyperinflated with reduced chest expansion
• Coarse crackles and wheeze (bronchiectatic)
• Portex reservoir (Portacath®) under the skin or Hickman line/scars for long‐term antibiotics plus PEG for malabsorption

Question 3

Genetics of Cystic fibrosis

Answer 3

• Incidence of 1/2500 live births
• Autosomal recessive chromosome 7q
• Gene encodes CFTR (Cl−channel)
• Commonest and most severe mutation is the deletion Δ508/ Δ508 (70%)

Question 4

Pathophysiology of Cystic fibrosis

Answer 4

Secretions are thickened and block the lumens of various structures:
* Bronchioles → bronchiectasis
* Pancreatic ducts → loss of exocrine and endocrine function
* Gut → distal intestinal obstruction syndrome (DIOS) in adults
* Seminal vesicles → male infertility
* Fallopian tubes – reduced female fertility

Question 5

Investigations for Cystic fibrosis

Answer 5

• Screened at birth: low immunoreactive trypsin (heel prick)
• Sweat test: Na+ > 60 mmol/L (false‐positive in hypothyroidism and Addison’s)
• Genetic screening

Question 6

Treatment

Answer 6

• Physiotherapy: postural drainage and active cycle breathing techniques
• Prompt antibiotics for intercurrent infections
• Pancrease® and fat‐soluble vitamin supplements
• Mucolytics (DNAse)
• Immunizations
• Double lung transplant (50% survival at 5 years)
• Gene therapy is under development

Question 7

Prognosis

Answer 7

Median survival is 35 years but is rising.
Poor prognosis if becomes infected with Burkholderia cepacia