Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.
2 min synopsisUK scopeSources checked 27 Aug 2026Clinical review pending
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Impending herniation, obstructive hydrocephalus or status epilepticus
Falling consciousness, new pupillary asymmetry, repeated vomiting with bradycardia or hypertension, rapidly progressive deficit, posterior-fossa obstruction or a seizure lasting five minutes or recurring without recovery requires immediate neurocritical stabilisation.
Action: Use ABCDE care, protect oxygenation and perfusion, treat status epilepticus by the emergency protocol, elevate the head and obtain urgent CT while contacting neurosurgery. Give dexamethasone for clinically significant vasogenic oedema after weighing diagnostic context, but if primary CNS lymphoma is suspected and the patient is stable, avoid corticosteroids before biopsy because they may erase diagnostic tissue.
Synopsis
Recognise mass-effect and seizure presentations, obtain urgent stabilising imaging and definitive tissue safely, integrate histology with molecular classification and coordinate maximal safe surgery, radiotherapy, systemic treatment, rehabilitation and long-term neuro-oncology support.
Primary brain tumours present through seizures, progressive focal deficits, cognitive or personality change, raised intracranial pressure or an incidental imaging finding.
Acute deterioration requires non-contrast CT first because it quickly detects haemorrhage, hydrocephalus, marked mass effect and a lesion needing urgent neurosurgery.
Contrast-enhanced MRI is the preferred definitive imaging test for characterising and mapping a suspected primary brain tumour; include diffusion and other protocol sequences.
Key red flags
A first focal or generalised seizure in an adult requires urgent assessment for a structural lesion and appropriate brain imaging.
Impending herniation
Falling consciousness, anisocoria, extensor response or cardiorespiratory instability requires immediate CT, neurocritical care and neurosurgical decompression assessment.
Investigation priorities
01
Emergency non-contrast CT brainFirst step
Rapidly detect haemorrhage, hydrocephalus, calcification, major oedema and midline shift in an acutely unwell patient.
02
Preferred contrast MRI brainPreferred
Characterise enhancement, diffusion, infiltration, haemorrhage, perfusion and anatomical relationship for biopsy, resection and radiotherapy planning.
Management branches
Acute mass effectStabilise pressure while preserving diagnosis
A patient has reduced consciousness, progressive deficit, severe vomiting, hydrocephalus or marked imaging mass effect.
Use ABCDE care, elevate the head, avoid hypoxia and hypotension, treat seizures and obtain urgent CT while contacting neurosurgery and neurocritical care.
Give dexamethasone for clinically important vasogenic oedema unless stable suspected lymphoma makes diagnostic preservation the higher priority, and treat hydrocephalus with urgent CSF diversion when indicated.
Key medicines
Temozolomide with glioblastoma radiotherapyGive temozolomide 75 mg/m² orally once daily throughout radiotherapy, including weekends, then commonly 150 mg/m² on days 1 to 5 of cycle 1 and 200 mg/m² on days 1 to 5 every 28 days for later cycles if tolerated.
Dexamethasone for tumour oedemaFor symptomatic vasogenic oedema use the lowest effective oral or intravenous dose, commonly 4 to 16 mg daily in divided doses according to severity, then taper as neurological pressure improves.
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.