13 - Cystic Fibrosis & Bronchiectasis

Question 1

What is the definition of bronchiectasis? Why does it occur?

Answer 1

dilitation and destruction of bronchial walls

retention of bronchial mucus (can be caused by dehydrated mucus in CF) –> bronchial infection, inflammation, edema –> recurrent infection, lung destruction, fibrosis/scarring

Question 2

Bronchiectasis is more common in [men/women].

Answer 2

Women

Question 3

In children, what is the most common cause of bronchiectasis?

Answer 3

cystic fibrosis

Question 4

What is the difference between cystic fibrosis and other forms of bronchiectasis?

Answer 4

Bronchiectasis is confined to the lungs whereas CF is a multisystem disease due to an autosomal recessive single gene mutation on chromosome 7 (encodes the cystic fibrosis transmembrane conductance regulator (CFTR))

Question 5

What is the most common CFTR mutation? What effect does it have on sweat glands and other organs?

Answer 5

∆F508 - defective processing and assembly (severe defect)

Sweat glands - Cl- is not transported back into cells

Other glands/organs - Cl- is not transported into the lumen –> Na+ and H20 reabsorption –> dehydrated mucus/secretions + ciliary dysfunction

Question 6

What feature of cystic fibrosis predisposes patients to recurrent pulmonary infection?

Answer 6

CFTR mutation is associated with an inflammatory response (neutrophils). DNA from degenerating neutrophils adds to the viscosity of sputum

Question 7

What are the criteria for making a cystic fibrosis diagnosis?

Answer 7

clinical symptoms of CF in at least one organ system AND evidence of CFTR dysfunction (sweat chloride test or genetic testing)

Question 8

How does cystic fibrosis lead to obstructive disease?

Answer 8

defective CFTR leads to inflammation and infection –> mucus hypersecretion, bronchial wall inflammation and destruction, mucus gland and bronchial epithelial hyperplasia –> increased airway resistance (in a minority of patients, there is also alveolar destruction that leads to decreased elastic recoil and decreased radial traction)

Question 9

What PFT pattern is seen with Cystic Fibrosis patients?

Answer 9

• usually obstructive pattern (may be mixed or restrictive in 10% of patients)
• hyperinflation occasionally
• reduced DLCO occasionally
• airway hyperreactivity can be present

Question 10

What illnesses can Cystic Fibrosis cause throughout the body?

Answer 10

• sinusitis
• bronchiectasis
• exocrine pancreatic insufficiency
• meconium ileus/bowel obstruction
• hepatobiliary disease
• infertility

Patients with milder variants often have single organ involvement

Question 11

What are the treatments for Cystic Fibrosis?

Answer 11

• chest physiotherapy
• antibiotics
• DNase
• predisone
• beta-2 agonists
• nebulized hypertonic saline
• NSAIDs
• azithromycin as anti-inflammatory
• new treatments focus on improving the function of the CFTR

inhaled corticosteroids have no benefit

Question 12

Why should anti-cholinergics not be used for a patient with Cystic Fibrosis?

Answer 12

they may cause a bowel obstruction

Question 13

What approaches can be used to help clear secretions from the lungs of a patient with Cystic Fibrosis?

Answer 13

• postural drainage
• flutter valve
• PEP mask
• percussion oscillatory vest

Question 14

What is the gold standard for diagnosing cystic fibrosis?

Answer 14

Sweat chloride test

Question 15

What 2 infections are most common in children with cystic fibrosis? What infection is most common in adults with cystic fibrosis?

Answer 15

Children - H. influenza and S. aureus

Adults - P. aeruginosa