Cystic Fibrosis Flashcards
Cystic fibrosis (CF) is
autosomal recessive
The gene for CF, located on the
long arm of chromosome 7, encodes for the cystic fibrosis transmembrane conductance regulator (CFTR), a chloride channel located on the apical surface of epithelial cells.
The altered chloride ion conductance in the sweat gland results in
in excessively high sweat sodium and chloride levels.
The most common mutation is
is a deletion of three base pairs resulting in the absence of phenylalanine at the 508 position (
which is still the standard diagnostic test for this disorder.
sweat chloride test,
The secretory and absorptive characteristics of epithelial cells are affected by abnormal CFTR,
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CF is a chronic progressive disease that can present with protein and fat malabsorption (failure to thrive, hypoalbuminemia, steatorrhea), liver disease (cholestatic jaundice), or chronic respiratory infection
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The respiratory epithelium of patients with CF exhibits
impermeability to chloride and an excessive reabsorption of sodium.
endobronchial colonization with bacteria, especially__________&_________
Staphylococcus aureus and Pseudomonas aeruginosa.
Chronic bronchial infection results in persistent or recurrent cough that is often productive of sputum, especially in older children.
Chronic airway infection leads to airway obstruction and bronchiectasis and, eventually, to pulmonary insufficiency and premature death.
Digital clubbing is common in patients with CF, even in those without significant lung disease. Chronic sinusitis and nasal polyposis are common.
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Allergic bronchopul- monary aspergillosis (ABPA) is a hypersensitivity reaction to Aspergillus in the CF airways.
Allergic bronchopul- monary aspergillosis (ABPA) is a hypersensitivity reaction to Aspergillus in the CF airways.
The treatment for ABPA is______
systemic corticosteroids (prednisone )and antifungal agents (itraconazole).
Minor hemoptysis is usually due to_______, but major hemoptysis is often caused by_______________
airway infection, bleeding from bronchial artery collateral vessels in damaged/chronically infected portions of the lung.
The inspissation of mucus and subsequent destruction of the pancreatic ducts result in the inability to excrete pancreatic enzymes into the intestine. This leads to
malabsorption of proteins, sugars (to a lesser extent), and especially fat. Fat malabsorption manifests clinically as steatorrhea (large, foul-smelling stools), deficiencies of fat- soluble vitamins (A, D, E, and K), and failure to thrive. Protein malabsorption can present early in infancy as hypoproteinemia and peripheral edema
Approximately 10% of patients with CF are born with intestinal obstruction caused by inspissated meconium (
meconium ileus).
In older patients, intestinal obstruction may result from thick inspissated mucus in the intestinal lumen (
distal intestinal obstruction syndrome [DIOS])
In adolescent or adult patients, progressive pancreatic damage can lead to enough islet cell destruction to cause_______ deficiency. This initially presents as glucose intolerance, but true diabetes that requires insulin therapy (CF-related diabetes) may develop
insulin,
The failure of the sweat ducts to conserve sodium and chloride may lead to___________________, especially in infants.
hyponatremia and hypochloremic metabolic alkalosis
