Evaluation of thunderclap headache (TCH)

TCH: thunderclap headache; CT: computed tomography; SAH: subarachnoid hemorrhage; CTA: computed tomography angiography; MRA: magnetic resonance angiography; RCVS: reversible cerebral vasoconstriction syndrome; ICH: intracerebral hemorrhage; SDH: subdural hematoma; MRV: magnetic resonance venography; CVT: cerebral venous thrombosis; CSF: cerebrospinal fluid; MRI: magnetic resonance imaging; RPLS: reversible posterior leukoencephalopathy syndrome.

* The sensitivity of head CT to detect SAH is reduced when imaging is obtained >6 hours from onset of TCH, when volume of bleeding is small, and with spinal sources of SAH.

¶ In addition to SAH, other causes of TCH that may be identified on neuroimaging include ICH, SDH, ischemic stroke, CVT, spontaneous intracranial hypotension, RPLS, and tumors.

Δ Vascular imaging in RCVS may be normal within the first two weeks after symptom onset. Evaluation to exclude other entities and/or repeat imaging may be warranted. Refer to UpToDate topic for additional details.

◊ Contraindications to lumbar puncture include cerebral edema/mass effect on head CT, coagulopathy, or suspected epidural spinal abscess. When lumbar pucture is contraindicated, neuroimaging with brain MRI as well as MRA and MRV of the head may be performed as the next step. Refer to UpToDate topics for additional information.