Which headache feature warrants urgent imaging or specialist referral?

• A. Thunderclap onset
• B. New headache with fever
• C. Headache worsened with rest
• D. Chronic daily headache

Answer: (A)

Recognizing a thunderclap headache as a red flag for a life-threatening intracranial bleed is the key idea here. A headache that peaks within seconds to a minute—often described as the worst headache of life—strongly suggests subarachnoid hemorrhage from an aneurysm or other acute vascular catastrophe. Because SAH can deteriorate quickly, this presentation requires urgent brain imaging and prompt specialist involvement. The typical first step is a non-contrast CT scan to look for bleeding, with neurosurgical or neurologic consultation as needed; if CT is negative but clinical suspicion remains high, a lumbar puncture may be performed to detect xanthochromia or other signs of hemorrhage.

The other scenarios raise different concerns but aren’t as immediately dangerous or require imaging as urgently. A new headache with fever could point toward meningitis or another infection and warrants swift evaluation, but the presentation is not as classically definitive for an acute bleed as thunderclap onset. Headache worsened with rest or chronic daily headaches describe patterns that are common and can often be managed outpatient unless additional red flags appear.