OSCE — Cystic Fibrosis · MBBS OSCE

Brief (to candidate)

You will assess a patient with a presentation consistent with Cystic Fibrosis.
You have 8 minutes to take a focused history, outline examination, investigations, and management including red flags.

Clinical context

Cystic fibrosis (CF) is an autosomal recessive multi-system disorder caused by loss-of-function mutations in the CFTR gene (chromosome 7q31.2; F508del accounts for ~70% of disease alleles). CFTR encodes a cAMP-regulated epithelial chloride/bicarbonate channel; its dysfunction produces dehydrated, viscous secretions across lungs, pancreas, gut, liver, sweat glands and reproductive tract. Pulmonary disease — chronic endobronchial infection (Staphylococcus aureus, Pseudomonas aeruginosa, Burkholderia cepacia complex) with bronchiectasis and respiratory failure — is the dominant cause of morbidity and mortality. Diagnosis rests on a positive newborn screen (immunoreactive trypsinogen), a sweat c

Candidate tasks

Clarify onset, severity, associated features, and red-flag symptoms.
State focused examination priorities.
List first-line investigations and any named score/criteria.
Give immediate resuscitation steps.
Outline definitive management with doses/routes where standard.
Name complications and disposition (ward / HDU / theatre / discharge safety-net).
Mention one special-population modifier (pregnancy, child, elderly, CKD).

Examiner checklist

Domain	Pass behaviours
Definition	Correct working diagnosis language
Assessment	Focused, prioritised, red flags sought
Investigations	Appropriate first-line + interpretation
Emergency care	ABC / time-critical actions first
Definitive care	Specific drugs/procedures, not generic phrases
Safety	Acute pulmonary exacerbation — increased cough, sputum volume or purulence, dysp
Safety	Massive haemoptysis (over 240 mL in 24 hours or recurrent significant bleeding)
Safety	Pneumothorax in CF — large or symptomatic — small-bore chest drain with suction,
Communication	Clear plan and safety-netting

Model outline

Lead with the working diagnosis and life threats. Resuscitate before definitive tests when unstable. Use guideline-standard therapy with named agents and doses. Document escalation criteria and follow-up. A safe candidate is specific, structured, and never delays critical care for non-urgent imaging.