Thunderclap headache — suspected SAH

PLAB 2 & PRES 3 · neurology · medium · 8 minutes

Candidate brief

You are an FY2 doctor/SHO in the Emergency Department. Ms Laura Bennett, 46, developed a sudden severe headache approximately 90 minutes ago. Assess her, explain your concerns and initiate appropriate investigation and management. Verbalise any examinations, investigations, treatments and escalation you would undertake.

What examiners look for

Thunderclap headache is a sudden severe headache that reaches maximum intensity within minutes. It is a red flag for subarachnoid haemorrhage and must not be assumed to be migraine. Establish the exact onset and time to maximum severity. Ask about vomiting, neck stiffness, photophobia, collapse, seizure, altered consciousness and neurological deficits. Arrange urgent non-contrast CT head. Diagnostic accuracy is highest when CT is performed within 6 hours of symptom onset. If a CT performed within 6 hours is negative and formally reported by a radiologist, lumbar puncture is not routinely required. Discuss the case with a senior decision-maker and seek specialist advice. If CT is performed more than 6 hours after onset and is negative, consider lumbar puncture. Wait at least 12 hours from symptom onset and test for bilirubin or xanthochromia using spectrophotometry. CT-confirmed SAH requires CT angiography and urgent discussion with a specialist neurosurgical centre. Do not perform lumbar puncture after CT has already confirmed SAH. Avoid aspirin and NSAIDs. Check anticoagulant and antiplatelet use and arrange urgent reversal when indicated. Specialists determine aneurysm treatment, blood-pressure management and medicines such as nimodipine. Do not delay transfer while attempting to complete definitive management locally.

Guideline references

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