Cystic Fibrosis Vignette

Question 1

What is the inheritance pattern of CF?

Answer 1

Autosomal recessive

Question 2

What is the most common mutation in CF?

Answer 2

F508 deletion in an ATP-binding cassette transporter gene on chromosome 7

Question 3

What is the incidence of CF in the United States?

Answer 3

Caucasian 1:3000

Hispanic 1:9000

Question 4

What is the median life expectancy for people living with CF in the US?

Answer 4

37 years

Question 5

What protein does the CF mutation encode for?

Answer 5

Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein

Question 6

What is the CFTR protein?

Answer 6

Epithelial chloride channel

Question 7

What problem does CFTR mutation cause?

Answer 7

Problems with moving salt (Cl- ) and water across cell membranes, resulting in abnormally thick secretions in various organ systems and critically altering host defense in the lung.

Question 8

What are the typical features of CF?

Answer 8

Greasy, bulky, malodorous stools
Failure to thrive dur to exocrine pancreatic insufficiency
Recurrent respiratory infections with opportunistic bacteria
Chronic sinus infections
Digital clubbing
Bronchiectasis
Sweat chloride > 60 mmol/L

Question 9

What is the false negative rate for newborn screening for CF?

Answer 9

1-5%

Question 10

What is exocrine pancreatic insufficiency

Answer 10

Failure of the pancreas to produce sufficient digestive enzymes to allow breakdown and absorption of fats and protein

Question 11

How is pancreatic insufficiency treated?

Answer 11

Enzyme supplements with meals to replace pancreatic enzymes, high calorie, high protein, and high fat diet, and fat soluble vitamin supplements

Question 12

What is meconium ileus?

Answer 12

A severe intestinal obstruction resulting from inspissation of tenacious meconium in the terminal ileum

Question 13

What is the predominant pathogen affecting CF patients?

Answer 13

Pseudomonas aeruginosa - associated with a more rapid decline in pulmonary function

Question 14

What is the standard treatment for pulmonary exacerbations in CF patients?

Answer 14

antibiotics and augmented airway clearance, often requires hospitalization for 1-2 weeks

Question 15

What treatments are recommended for CF?

Answer 15

Regular CF care at a CF Foundation-accredited care center
Manage exocrine pancreatic insufficiency
Daily salt supplement
Airway clearance treatment
Antibiotic therapy targeting common CF bacteria
Anti-inflammatory treatments
CFTR modulators

Question 16

Where do CF patients lose salt?

Answer 16

In sweat - chloride movement is reversed from in lungs and GI tract, since the body tries to recapture salt from sweat