Cystic Fibrosis Flashcards
Cystic Fibrosis Is.. (2 facts)
- autosomal recessive, inherited
- multi system disease that is characterized by secretions of abnormally viscous bodily fluids, especially in the pancreas, lungs, and sweat glands
CF Epidemiology (5 facts)
- Most common genetic disease among caucasians
- Most common cause of chronic lung disease in children and young adults
- Median age of diagnosis is six months
- About 30,000 patients in the US, about 1000 new cases per year
- prevalence is related to ethnicity (1/2500 caucasians)
CF Etiology (4 facts)
- Autosomal recessive inheritance of mutations in a single gene
- Encodes for cystic fibrosis transmembrane regulator (CFTR)
- > 1900 mutations divided into 6 classes
- Most common mutation is the deletion of F508 (60-75%)
CF Mutation Classes (6 classes)
Class I: No protein synthesized; no function (Nucleus)
Class II: No trafficking to the cellular surface; no function (ER)
Class III: No function at cell surface; no function
Class IV: Less function at the cell surface
Class V: Less protein at cell surface
Class VI: Less stable at cell surface
CF Pathophysiology (4 facts)
- CFTR is a membrane bound Cl- channel
- Helps regulate fluid and electrolyte balance in epithelial cells lining airways, pancreatic ducts, and sweat glands
- Located on apical surface (facing the lumen, the opening)
- **Cl-, Na+ and water are always together
CFTR Function and Dysfunction (sweat glands)
- CFTR is responsible for reabsorbing chloride from sweat and sodium follows the chlorine naturally through another channel.
- CFTR disfunction leads to sweat with more concentrated salts
CFTR Function and Dysfunction (the lungs)
- CFTR dysfunction leads to Chlorine isolation inside of the lung cell.
- Na+ and h2o follow Cl- and are reabsorbed into the cell from the mucus
- The mucus becomes severely dehydrated and viscus and cannot move through the lungs in CF
CF Pathophysiologic Triad (3 facts)
- Stepwise (in lungs): Viscous mucus in lung causes chronic infection, inflammation, airway obstruction, bronchiectasis (walls of bronchi are thickened by chronic inflammation) and bronchiolectasis
- Excess salt in sweat, saliva and tears
- Pancreatic enzyme deficiency causing poor digestion, malabsorption
CF Pathophysiology in the lungs (4 factors)
CF results in:
- Impaired endogenous antimicrobial enzymatic activity
- Impaired mucocillary transport
- Impaired other defenses
- Inflammation, Remodeling, Genetic adaptation
CF Diagnosis: Pulmonary
Clinical presentation varies with mutation (can also be pancreatic)
1. Pulmonary: Recurrent infection, obstructive lung disease, persistent cough, exercise intolerance, hemoptysis (coughing blood), tachypnea (rapid breathing), barrel chest, hypoxemia (decreased O2 to tissues because of decreased oxygen in lungs
CF diagnosis: GI
Meconium ileus at birth (dehydration of the bodily fluid leads to baby first poop to become stuck and cannot pass pathognomonic-absolutely diagnostic), failure to thrive, steatorrhea (excessive fat in stool)
CF diagnosis: Other
Digital clubbing, infertility (males)
CF Patient Assessment (APS)
- Arterial blood gas (how well oxygenated blood is)
- Pulmonary function (spirometry, FEV, tidal volume, respiratory rate)
- Sweat test (chloride sweat test)
CF Sweat test
-Quantitative pilocarpine iontophoresis test (QPIT(:
1. Normal = 60 mEq/L
2. CF= >60mEq/L
For 40 to 60 mEq/L, retest and/or look for other clinical signs
CF Complications: Acute
Common and usually serious
1. Acute: pneumonia, atelectasis (collapsed lung), pneumothorax (air leaking out of the lung), malnutrition, dehydration, pancreatitis, respiratory failure