PANCE Neurology Practice Test

A thunderclap headache is defined by a sudden onset that reaches maximum intensity within seconds, signaling a potentially life‑threatening brain event. The most common cause is rupture of a saccular (berry) aneurysm leading to nontraumatic subarachnoid hemorrhage. When an aneurysm ruptures, blood rapidly fills the subarachnoid space and irritates the meninges, producing an abrupt, worldwide severe headache often described as the worst headache of life. This presentation is an emergency and demands rapid evaluation: a noncontrast head CT is the first test to detect blood; if CT is negative but suspicion remains, a lumbar puncture can reveal xanthochromia or elevated red blood cell count in the CSF; vascular imaging then identifies the aneurysm. The standard management focuses on securing the aneurysm to prevent rebleeding and using measures like nimodipine to reduce the risk of vasospasm. Other headache types can be sudden, but they usually do not produce this abrupt, maximal-intensity onset with the potential for subarachnoid blood.