Brain and spinal tumours: Viva

This is a branching oral built to probe the reasoning that holds the location and the molecular classification at the centre, and to expose the candidate who has memorised the headline without the corners. The questions escalate from the framing to the stabilisation, the imaging, and the definitive management, with deliberate probes into the pitfalls. ^[3]

Opening question: framing the problem

The examiner opens with the history and the examination and asks: how do you frame this problem in a single sentence, and what is your first priority? ^[2]

A strong answer names the syndrome of raised intracranial pressure with a posterior fossa sign, the ataxia, and states that the progressive early morning headache and vomiting with the papilloedema is a tumour until imaging proves otherwise. The first priority is the relief of the raised pressure, because the obstructive hydrocephalus from a posterior fossa mass can progress to the herniation within hours. ^[11]

Model answer. This child has raised intracranial pressure from a posterior fossa tumour with obstructive hydrocephalus, almost certainly a medulloblastoma until imaging proves otherwise. My first priority is to relieve the pressure with the dexamethasone and the neurosurgical management of the hydrocephalus, and to reach the urgent magnetic resonance imaging of the brain and the whole neuraxis. ^[3]

Probe one: the resuscitation

The examiner presses: tell me exactly what you do in the first four hours, and why you choose the dexamethasone. ^[11]

A strong answer reproduces the dexamethasone at zero point one to zero point two milligrams per kilogram per dose every six hours for the vasogenic oedema, tapered after the surgery, with the head elevation and the isotonic fluids. The hydrocephalus is managed with the external ventricular drain at the surgery or before it, and the endoscopic third ventriculostomy is the alternative. The falling consciousness or the Cushing response triggers the emergency measures. ^[11]