Cystic Fibrosis

• • Serious congenital disorder, autosomal recessive disorder

  • Most common mutation is deletion of amino acid in position 508 (Phe)

  • Defect in chloride transport, results in more NaCl absorption in the airway

  • Defect occurs in apocrine sweat glands tracheobronchial tree, pancreas, GI tract

  • Airway secretions are low in volume and high in viscosity

  • Mucoid plugs form and are rubbery, semisolid, gray to greenish yellow in color resulting in impaction

  • Often history of recurrent upper respiratory tract infection, fever, and chest pain

Epidemiology

• • 1 in 25 whites heterozygous carrier

  • 1 in 2000 homozygous

  • Single most common mutation characterized

Symptoms and Signs

• • Recurrent respiratory infection

  • Fever

  • Chest pain

  • Meconium ileus in newborn, meconium in terminal ileum causes obstruction

Laboratory Findings

• • Positive sweat test (NaCl in sweat)

Rule Out

• • Bronchogenic carcinoma

  • Bronchiectasis

  • Abscess

  • Bacterial pneumonia

  • Lipoid pneumonia

  • Pulmonary eosinophilic granuloma

  • Löffler syndrome

• • Chloride sweat test

  • Pilocarpin iontophoresis (NaCl concentrations exceeding 60 mEq/L)

Surgery

• • Double lung transplant

Indications

• • End stage pulmonary disease

Complications

• • Bronchitis, bronchiectasis

  • Pulmonary fibrosis

  • Emphysema

  • Lung abscess

  • Complication of transplant: Chronic bronchitis obliterans major obstacle and cause of eventual transplant failure

Prognosis

• • 1-year survival, 85%

  • 5-year survival, 50%

References