OSCE — CNS Infections — Meningitis, Encephalitis, Brain Abscess, TB, Cryptococcal, Neurocysticercosis · MBBS OSCE

Brief (to candidate)

You will assess a patient with a presentation consistent with CNS Infections — Meningitis, Encephalitis, Brain Abscess, TB, Cryptococcal, Neurocysticercosis.
You have 8 minutes to take a focused history, outline examination, investigations, and management including red flags.

Clinical context

CNS infections span the meninges (meningitis), brain parenchyma (encephalitis, abscess), or both (meningoencephalitis). Acute bacterial meningitis is a time-critical emergency: fever, headache, neck stiffness and altered mental status (all four in about 44 percent of cases) demand empiric IV antibiotics within one hour — ceftriaxone 2 g IV BD plus vancomycin, adding ampicillin for Listeria in the over-50, pregnant, or immunocompromised — with dexamethasone 10 mg IV q6h for four days given before or with the first antibiotic dose. CSF analysis distinguishes bacterial (neutrophils, low glucose, high protein) from viral (lymphocytes, normal glucose), TB (low glucose, high lymphocytes, ADA raise

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	Fever, headache, neck stiffness and altered mental status — treat as bacterial m
Safety	Petechial or purpuric non-blanching rash with shock — meningococcal septicaemia;
Safety	Fever with altered behaviour, seizures or aphasia — viral encephalitis; start IV
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.