An atypical case of spontaneous intracranial hypotension.

Spontaneous intracranial hypotension (SIH) is a well-known clinical syndrome associated with the typical magnetic resonance imaging findings of pachymeningeal enhancement, downward cerebral displacement and subdural fluid collections. Atypical clinical presentations are not infrequent and often misdiagnosed. We report a case of SIH presenting with thunderclap headache and CT scan evocative of subarachnoid hemorrhage. We discuss the unusual presentation of this patient and the differential diagnosis of this case.