Station 1.12: Cystic fibrosis

Question 1

Clinical signs

What are the clinical signs of Cystic fibrosis?

Cystic fibrosis

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

Answer 1

• 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 2

Discussion - genetics

Describe the Genetics of Cystic fibrosis?

Cystic fibrosis

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

Answer 2

• 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 3

Discussion - pathophysiology

Describe the Pathophysiology of Cystic fibrosis?

Cystic fibrosis

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

Answer 3

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 4

Discussion - investigations

Describe the investigations for Cystic fibrosis?

Cystic fibrosis

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

Answer 4

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

Question 5

Discussion - treatment

Describe the treatment for Cystic fibrosis?

Cystic fibrosis

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

Answer 5

• 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 6

Discussion - prognosis

Describe the prognosis for Cystic fibrosis?

Cystic fibrosis

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

Answer 6

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