Widening the spectrum of secondary headache: intracranial hypotension following a non-aneurysmal subarachnoid hemorrhage.

Background: Intracranial hypotension has been associated with a wide spectrum of neurological conditions including chronic non-aneurysmal and acute aneurysmal subarachnoid hemorrhage.

Case: A 59-year-old man presented with a non-aneurysmal subarachnoid hemorrhage in a perimesencephalic pattern after a mild physical exertion. In the course of the disease, a magnetic resonance imaging of head and spine displayed intracranial hypotension that resolved spontaneously.

Discussion: Long-standing intracranial hypotension has been reported as the cause of chronic subarachnoid hemorrhage and a single case of intracranial hypotension as the consequence of intracranial pressure fluctuations after acute aneurysmal subarachnoid hemorrhage has been described. This is the first description of intracranial hypotension caused by acute non-aneurysmal subarachnoid hemorrhage. We hypothesize that blood in the subarachnoid space could have determined a spine cerebrospinal fluid leak through intracranial pressure fluctuations or mechanical action, causing arachnoiditis and possibly a dural tear.