Cystic Fibrosis

Question 1

Define Cystic fibrosis

Answer 1

autosomal recessive condition caused by a mutation in chromosome 7 at the CF transmembrane conductance regulator (CFTR) gene

Question 2

What is the result of this mutation?

Answer 2

(1) Increased sodium absorption
(2) abnormal chloride secretion in the epithelial cells lining the airways.

= This leads to thicker mucus impairing the function of cilia - repeated chest infections

Question 3

Clinical presentation

Answer 3

child aged 0-2 with recurrent infections, large offensive stools and failure to thrive

Question 4

What are the respiratory symptoms

Answer 4

• Recurrent respiratory infections
• Chronic daily cough and sputum production
• Dyspnoea
• Nasal polyps
• Haemoptysis

Question 5

What are the GI symptoms

Answer 5

• Failure to thrive in infancy and low BMI in adults
• Meconium ileus in infancy (bowel obstruction)
• Distal intestinal obstruction syndrome in YAs
• Big appetite in kids
• Malabsorptive stool with steatorrhoea due to pancreatic insufficiency
• Also gallbladder stones, cirrhosis

Question 6

What are some other symptoms?

Answer 6

• Salty sweat
• Infertility in males - bilateral absence of vas deferens
• CF-related diabetes

Question 7

Signs of cystic fibrosis

Answer 7

• Cyanosis
• Clubbing
• Chest hyperinflation
• Bilateral coarse crackles

Question 8

Investigations

Answer 8

• Sweat test - diagnostic
• Genetic testing for CFTR mutations

Question 9

Management for Respiratory problems are what?

Answer 9

= In the early, pre-infected stages, mucus clearance, preventing infection and maintaining good lung function are the main aims

(1) Chest physiotherapy should be given twice daily

(2) Regular sputum samples are sent for bacterial culture

(3) Prophylactic antibiotics - often prophylactic agents to reduce staph. aureus (e.g. flucloxacillin)

(4) CFTR modulators are relatively new drugs which improve flow through CFRT -kaftrio→ elexacaftor, tezecaftro, ivakaftor

(5) Consider lung transplant once FEV1 <40%

Question 10

Management for liver

Answer 10

TIPSS for portal hypertension

Question 11

Management for pancreas

Answer 11

CREON for exocrine failure, diabetes monitoring for endocrine failure

Question 12

management for bowels

Answer 12

mucous blocks intestine (DIOS), prevent/treat with laxatives, fluids and hydration

Question 13

Management when an individual gets an exacerbation

Answer 13

• Increase chest physiotherapy
• Add two weeks of antibiotics appropriate to the most recent sputum sample

Question 14

Who is cystic fibrosis most common in?

Answer 14

white people

Question 15

Class 1 means

Answer 15

massive defect in CFTR

Question 16

Class 2 means

Answer 16

protein is produced but is the wrong shape

Question 17

Class 3 means

Answer 17

protein is the right shape but wont open

Question 18

Class 4 means

Answer 18

protein is right shape and opens, but doesn’t let enough chlorine through

Question 19

Class 5 means

Answer 19

Protein works but not enough is produced