Cystic fibrosis

Question 1

Cystic fibrosis

Answer 1

• Autosomal recessive mutation in CFTR gene
• Delta F508 is the most common mutation
• Defective sodium and chloride transport across epithelial cell

Question 2

Symptoms

Answer 2

1. Recurring chest infection
2. Frequent wet sounding cough
3. Occasional wheezing and shortness of breath
4. Difficulty putting on weight

Question 3

Clinical features

Answer 3

1. Sweat duct abnormalities - more chloride in sweat
2. Pancreatic duct dysfunct - Thick secretions block the pancreatic duct preventing enzymes reaching the intestine
   •Acute pancreatitis - enzyme accumulation breaks down pancreatic tissue
   •Protein and fat not digested properly -> Steatorrhea
3. Vas deferens abnormality - lack vas deferens

CF sufferers may be infertile

4. Lung problems
   •Lack of mucocilary escalato means pathogens colonise the lungs
   -> clubbing
   -> Bronchiectasis
   -> Respiratory failure - leading cause of CF death

Question 4

Diagnosis

Answer 4

• Immunoreactive trypsinogen is increased with new borns with CF,
- released into blood when pancreas is damaged
• Sweat test - Sodium and Chloride ions in sweat will be increasedd
• Chest radiograph

Question 5

Pathophys of CF

Answer 5

• Channel pumps Cl- ions out
• Draw water into CL- secretions
• Thins out the mucus
• Dysfunctional channel leaves mucus secretions overly thick allowing for pathogens to stick and infect lungs

Question 6

Newborns with CF

Answer 6

Meconium ileus - first stool is very thick and sticky thus it may become stuck in the intestines

Question 7

Bronchiectasis

Answer 7

•chronic inflammation causes brochi/bronchioles to get damaged and dilate
• inflammation causes mucus plugs in the airway
-> obstructs airway thus obstructive pattern of disease
•

Question 8

Causes of Bronchiectasis

( chronic inflammation)

Answer 8

1. Cilary dyskinesia - cilia don’t move normally
2. CF- mucus is thick and sticky thus is hard to sweep
3. Airway obstruction - tumor within or outside airway. blockage prevents mucus clearance
   - mucus is stuck in airways
   - bacteria trapped multiply
   - pneumonia
   - repeated bouts of this causes chronic inflammation

Question 9

Bronchiectasis pathophys

Answer 9

1. Chronic inflammation causes immune cells and cytokines to
   - damage cillated epithelial cells
   - destroy elastin fibres in walls of airways
2. Overtime airways become clogged with mucus and dilated
3. Fibroblasts try to repair the damage by depositing collagen
4. Loss of elastin and build up of collagen makes the lungs less elastic and more stiff

Question 10

Clincial features

Answer 10

1. Pulmonary hypertension and Right sided heart failure - wide spread arteriole constriction as a result of damage to lungs causing pulmonary hypoxia
   - this increases vascular resistance in turn

Question 11

Symptoms

Answer 11

1. Wheezing
2. Coughing
3. Shortness of breath
4. Foul smelling mucus
5. Long term hypoxia -> digital clubbing

Question 12

Diagnosis

Answer 12

1. CT scan - dilated bronchi and bronchioles

2. Pulmonary function test - decrease in lung capacity