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Unformatted text preview: Cystic Fibrosis Board Review February 11, 2008 Cystic Fibrosis
Mutation in CFTR gene--epithelial chloride gene--epithelial channels mutation causes decreased Cl transport and Na hyperabsorption leading to thick secretions most common mutation is delta-F508 (70%), deltahowever, over 1500 mutations exist Autosomal recessive inheritance 1 in 25 to 30 Caucasians is a carrier, making disease prevalence 1 in 3300 The lungs
Major cause of death (usually by 30 years) is progressive respiratory disease. Increased secretions lead to obstruction, leading to repeated infections (especially psuedomonas), bronchiectasis, and decline in lung function, causing respiratory failure often with a component of pulmonary hypertension and cor pulmonale The pancreas
Pancreatic ducts are obstructed by thick secretions, leading to decreased excretion of enzymes into the intestine. Pancreas is autodigested and replaced by scar tissue, resulting in decreased breakdown of fat and protein Fat and protein malabsorption, fat-soluble fatvitamin deficiency Fat soluble vitamins
A (retinol) blindness E (tocopherol) ptosis proprioception truncal ataxia D rickets K prolonged prothrombin time 2, 7, 9, 10--vitamin K 10--vitamin dependant factors Presentation
General FTT meconium ileus in neonate foul smelling stools, bloating stools, rectal prolapse impaction/obstruction pancreatitis low albumin, low sodium cholelithiasis, cholecystitis cirrhosis, portal hypertension neonatal hyperbilirubinemia fat soluble vitamin deficiency Respiratory clubbing asthma COPD, barrel chest productive cough, hemoptysis nasal polyps pneumothorax/mediastinum cor pulmonale, RVH dehydration (low Na, low Cl) metabolic alkalosis (esp neonate) DM heat stroke infertility in males GI Metabolic GU Diagnosis
Elevated serum trypsinogen in neonate Gene testing 87 mutation panel (92% sensitivity) 1300 mutation panel (97 - 99% sensitivity) GOLD STANDARD: CHLORIDE SWEAT TEST <40 mEq/L--negative mEq/L--negative 40 - 60 mEq/L--equivocal, needs repeat mEq/L--equivocal, >60 mEq/L--positive, needs confirmation mEq/L--positive, Diagnosis
False positives adrenal insufficiency nephrogenic DI hypothyroidism mucopolysaccharidosi s G6P deficiency hypoproteinemia anemia from poor nutrition False negatives severe malnutrition with edema too little sweat inexperienced tester Treatment
For acute respiratory infections: hospitalization with PCN and aminoglycoside, pulmonary toilet baseline pulmonary therapy aerosols (bronchodilation) chest physical therapy aerosolized antibiotics systemic steroids or expectorants--not expectorants--not indicated Treatment
Nutritional therapy high fat, high protein diet pancreatic enzyme replacements vitamin and mineral supplements Other no support for growth hormone pulmonary transplant--must transplant both transplant--must lungs simultaneously! Prognosis
Life expectancy of about 32 years at best Poorer prognosis in: females low SES severe neonatal pulmonary disease ...
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- Spring '11