Term
| How is cystic fibrosis inherited? |
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Definition
An autosomal recessive disorder - carriers have no symptoms. Mother is usually tested
**Genetic testing, and sweat chloride test > 60 |
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Term
| What causes cystic fibrosis? |
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Definition
Abnormality in CFTR, a chloride channel, on chromosome 7. F508 most common mutation.
- Cl accumulates in ductul lumen of skin, very salty sweat
- Lung - Cl accumulates in lumen, fluid/secretions build up
- Pancreas - malabsorption and diabetes
- Intestines - increased secretion can block
- Liver - Cirrhosis leads to varices and portal HTN
- Sweat glands - NaCl excreted --> hyponatremia
- Reproduction - obstruction leads to infertility |
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Term
| How does CF affect the lungs? |
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Definition
Most likely to kill
Inflammation, infection, and obstruction
Measured by FEV1 - Mild (70-89), Moderate (40-69), and severe (less than 40) |
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Term
| What bacteria can colonize a CF patient? |
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Definition
- Pseudomonas aeruginosa** most common
- Staph aureus - MSSA or MRSA
- H. influenza - vaccinated against
- B. cepacia - uncommon, a negative indicator. |
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Term
| How does cystic fibrosis affect the GI tract? |
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Definition
- Exocrine - 90%. Deficiency in pancreatic enzymes and fat soluble vitamins - must be supplemented
- Endocrine - diabetes. ketoacidosis rare. |
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Term
| What are signs/symptoms of cystic fibrosis? |
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Definition
- Pulmonary - Cough, increased sputum, pneumonia, SoB/Dyspnea
- GI/endocrine - meconium ileus, pain/distention, N/V, steatorrhea, malnutrition, hyperglycemia |
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Term
| What agents are used for pulmonary symptoms of cystic fibrosis? |
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Definition
- Ivacaftor/Kalydeco - only for G551D mutation. 150 mg BID with high fat meals. A CFTR potentiator
- Dornase alfa/Pulmozyme - a mucolytic via nebulizer. Loosens sputum
- Hypertonic 3 or 7% saline - a mucolytic via nebulizer
- Tobramycin/TOBI - inhaled to prevent PSEUDOMONAS. Month on, month off
- Aztreonam/Cayston - inhaled to prevent pseudomonas, month on month off
- Azithromycin/Zithromax - does not cover pseudomonas, pleiotropic |
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Term
| How are GI symptoms improved in cystic fibrosis patients? |
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Definition
| - Pancreatic enzymes/Creon or Zenpep - reduces fat in stool. Aids in digestion. |
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Term
| How is a cystic fibrosis exacerbation treated? |
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Definition
Look for oxacillin resistance. Is it MRSA?
- Double coverage for Pseudomonas aeruginosa - beta lactam + aminoglycoside OR FQN OR Colistin
- MRSA? Add Vancomycin or Linezolid/Zyvox |
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Term
| What are pharmacokinetic considerations in cystic fibrosis patients? |
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Definition
- Increased clearance
- Increased Vd
- Increased metabolism
- Decreased lung penetration
**INCREASED DOSES |
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