Cystic fibrosis

Question 1

What causes cystic fibrosis?

Answer 1

Autosomal recessive cystic fibrosis transmembrane conductance regulator (CFTR) gene. This affects chlorine channels so there is defective chlorine secretion

Question 2

What are the clinical features of cystic fibrosis?

Answer 2

Neonates have failure to thrive
When older:
resp - recurrent infections, bronchiectasis, pneumothorax
Gastro: pancreatic insuffieciency, gallstones, cirrhosis
Other - male infertility, osteoporosis, arthritis, vasculitis

Question 3

What are the signs present in cycstic fibrosis?

Answer 3

Bilateral coarse crackles, cyanosis, finger clubbing

Question 4

How can you diagnose cycstic fibrosis?

Answer 4

With a sweat test that shows sodium and chlorine to be elevated, chlorine is usually > sodium
Genetic screening can be done
Faecal elastase useful for pancreatic exocrine dysfunction

Question 5

What are the investigations for cystic fibrosis?

Answer 5

Bloods - almost all
Bacteriology - sputum culture
Radiology - CXR shows hyperinflation and bronchiectasis
Abdo ultrasound - cirrhosis
Spirometry - obstructive defect

Question 6

What is the management of cystic fibrosis?

Answer 6

Multidisciplinary management e.g. physician, GP etc
Chest - physio, antibiotics for obstruction
Chronic pseudomonas infection is an important indicator of survival
Gastro - treatment with pancreatic enzyme replacement and vitamins for malabsorption