Cystic Fibrosis Fred Hill, MA, RRT. Overview Cystic fibrosis is the most common fatal, inherited...
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Transcript of Cystic Fibrosis Fred Hill, MA, RRT. Overview Cystic fibrosis is the most common fatal, inherited...
Overview
• Cystic fibrosis is the most common fatal, inherited disease in the U. S.
• CF results from a defective autosomal recessive gene– One copy of gene = carrier– Codes for a protein responsible for salt
transport by epithelial cells– Defective gene found on chromosome #7– Several hundred mutations possible– ~12 mutations identified, delta F508 most
common (68%)
Overview
• Genetic defect expressed when two carriers produce progeny– 25% chance of CF– 50% chance of carriers– 25% chance of normal
• Affects all racial and ethnic groups, but Caucasians of northern European ancestry most often affected
Statistics of CF
• Median age of survival– 1960s: ~2-4 yrs– Early 1990s: ~25 years– 2000: ~30 years– 2006: ~37 years
• Incidence– 30,000 Americans, 20,000 Europeans, 3,000
Canadians– In U. S., 12,000,000 carriers– 2500 CF babies born annually in U. S.
Statistics of CF
• Incidence– Caucasians: 1 in 1600 births– African Americans: 1 in 13,000
births– Asian Americans: 1 in 50,000
births– 1 in 22 Caucasians are carriers
Genetics and Dysfunction
• Defective gene identified in 1989• Bichemical abnormality called cystic
fibrosis transmembrane regulator (CFTR)
• Interferes with Cl- transport across epithelial membranes, primarily manifested in exocrine glands
Respiratory Related Conditions
• Repeated infections• Chronic cough• Recurrent bronchitis• Recurrent pneumonia• Bronchiectasis• Pneumothorax
• Hemoptysis• Digital clubbing• Cor pulmonale• Sinusitis• Allergic bronchopulmonary
asperigillosis• Nasal polyps
Other Manifestations
Gastrointestinal• Failure to thrive• Greasy, foul-smelling stools• Meconium ileus• Distal intestinal obstruction• Hyperglycemia• Abdominal discomfort• Rectal prolapse
Hepatobiliary System• Liver disease• Prolonged neonatal Jaundice
Reproductive Tract• Delayed puberty• Infertility
Sweat Glands• High salt content
Diagnosis
• Genetic testing• Sweat test• Other
– Prenatal diagnosis– Medical history– Immunoreactive trypsinogen test– Nasal potential difference measurement– Pulmonary function testing
Sweat Chloride Test
• Use pilocarpine and a mild electrical current to promote sweat production
• Wrap with pad and plastic covering• Collect and analyze sweat for chloride• Positive test
– Cl- > 60 mmoles/L in children
– Cl- > 80 mmoles/L in adults
Treatment
• Antibiotics• Improved nutrition• Antiinflammatories• Pancreatic enzyme supplements• Bronchial hygiene• Bronchodilators & mucolytics• Physical therapy & exercise• Lung transplantation
Airway Clearance Techniques
• Chest physical therapy• Forced expiratory technique• Active cycle breathing• Positive expiratory pressure• Autogenic drainage• Flutter device• Vest• Exercise
Lung Transplantation
• Limitations– High cost– Posttransplantation comlications
• Oliterative bronchiolitis (30% to 50% in 3-5 years)• 1 year survival: ~72%• 3 year survival: 55%• 5 year survival: 49%
Lung Transplantation
• General criteria– <60-65 years old– No significant extrapulmonary complications– No steroid regimen >20 mg prednisone daily– No malignancy within past 5 years– 20% of ideal body weight– Ambulatory and capable of pretransplantation rehab program– Motivated and likely to comply with regimen – No smoking or drug/alcohol abuse– No major psychiatric problems– Adequate financial resources
Lung Transplantation
• Severity of disease criteria– FEV1 <30%
– PaO2 < 55 mm Hg
– PaCO2 > 50 mm Hg
– Suffering from an unacceptable quality of life
Lung Transplantation
• Potentially inadvisable situations– Significant liver disease– Severe malnourishment– Extensive pleural scarring– Ventilator dependent– Colonized by Burkholderia cepacia– Aspergilloma with extensive pleural reaction– Severe osteoporosis with history of vertebral
compression