Spontaneous Intracranial Hypotension Followed by Intracranial Hypertension.

Spontaneous intracranial hypotension is a secondary cause of headache caused by suspected cerebrospinal fluid leaks. It is associated with vascular changes that may predispose to superficial siderosis. When treated with an epidural blood patch, rebound intracranial hypertension may ensue. A 55-year-old man presented with orthostatic headaches responsive to rest and hydration. Brain magnetic resonance revealed subdural collections, consistent with intracranial hypotension. Three weeks later, the patient experienced sudden severe holocranial headache and spontaneous subarachnoid hemorrhage was found. This resulted in rebound intracranial hypertension with bilateral papilledema and sixth-nerve palsy, which completely resolved with acetazolamide. Spontaneous intracranial hypotension may predispose to subarachnoid hemorrhage through vascular compensatory changes. Blood in subarachnoid space may seal the hidden cerebrospinal fluid leak or trigger an inflammatory reaction, leading to rebound intracranial hypertension, a well-known epidural blood patch complication.