09: Cystic Fibrosis

Question 1

Cystic fibrosis

Answer 1

• Chronic, progressive life-limiting autosomal recessive disease characterized by chronic respiratory dz, pancreatic insufficiency, elevation of sweat electrolytes and male infertility
• Clinical presentation
  
  • Cl- channel defect in exocrine glands
  • Thick secretions
  • Recurrent pneumonia
  • Pancreatic insufficiency
  • ↑salt content in sweat
  • Male infertility

Question 2

Genetics of CF

Answer 2

• CFTR = cAMP regulated chloride channel located in apical membrane of glandular epithelium
  
  • Long arm of chromosome 7 (D508 most common mutation, block in processing [70%])

Question 3

Sweat Test

Answer 3

• Normal: < 40 mEq/L
• Borderline: 40-60 mEq/L
• Positive: > 60 mEq/L

Question 4

CF microbiology

Answer 4

• Children/teens: S. aureus
• Adults: Pseudomonas aeruginosa

Question 5

Hypertrophic osteoarthropathy

Answer 5

• Clubbing
• Periosteal new bone formation
• Proliferation of skin and osseus tissue at distal parts of extremities