CF

Question 1

Outline the pathophysiology of CF

Answer 1

Autosomal recessive

Chromosome 7 defect = CF transmembrane conductance regulator gene mutation = ineffective cell surface chloride transport = reduced airway surface liquid = impedes mucociliary escalator/clearance = enables bacterial growth (biofilm)

Pancreas = duct usually occluded
GI = viscous mucus secreted causing meconium ileus. Cholestasis causing neonatal jaundice
Repro = vas deferens absence

Question 2

How does CF typically present?

Answer 2

Neonates

• Meconium ileus = newborns, bowel blocked by sticky secretions, signs of obstruction (bilious vomiting, abdo distension)
• Failure to thrive
• Prolonged neonatal jaundice

Infancy

• Chest infections
• Pancreatic insufficiency: steatorrhoea

Childhood

• Rectal prolapse
• Nasal polyps
• Sinusitis
• Bronchiectasis

Adolescence

• Pancreatic insufficiency: DM
• Chronic lung disease
• Distal intestinal obstructive syndrome (DIOS), gallstones, liver cirrhosis

Question 3

How should suspected CF be Ix?

Answer 3

Immunoreactive trypsin (IRT)
- trypsinogen blocked from entering gut, builds up in blood 

Chloride sweat test = [electrolyte], chloride >60 suggestive (x2)
- pilocarpine soaked pad + electrode

CXR = hyperinflation

Microbiology = cough swab, sputum sample

Glucose tolerance test

LFTs, coag, bone profile

Spirometry

Genetic testing - CFTR gene

*** heel prick test - IRT, then CFTR gene mutation screen

Question 4

How is CF best managed?

Answer 4

Twice-daily chest physio

Inhaled DNase = reduce viscosity by digesting DNA abundant in sputum

Hypertonic saline

Encouraged physical exercise

Pancreatic enzyme supplementation = creon

Vit A, D, E supplements

Build up milkshakes to supplement meals

Monitor growth

Continual microbiological assessment = sputum cultures, Abx (2w)

Regular azithromycin

Question 5

Outline the possible complications of CF

Answer 5

• Allergic bronchopulmonary aspergillosis
• Bronchiectasis
• Haemoptysis
• Pneumothorax
• Respiratory failure
• Nasal polyps
• Rectal prolapse
• Distal intestinal obstructive syndrome
• Liver disease = cholestasis, gallstones, cirrhosis
• CF related DM (CFRD)
• Delayed puberty