Spontaneous Intracranial Hypotension

Excerpt

The intracranial pressure is controlled by the production, flow, and absorption of the cerebrospinal fluid. If there is an alteration in these processes leading to an alteration in the CSF pressure, there is a manifestation of neurologic symptoms that is most commonly a headache. Spontaneous intracranial hypotension (SIH) presents with postural headache and low cerebrospinal fluid (CSF). The underlying cause is usually a CSF leak.

In the majority of the cases, brain magnetic resonance imaging (MRI) will show diffuse meningeal enhancement. However, a few cases have been reported in which the patient had a non-orthostatic headache, normal CSF pressure, and no meningeal involvement on MRI. Historically, different terms have been used to describe this process, such as spontaneous or idiopathic low CSF pressure headache, liquorrhea, low CSF volume headache, CSF hypovolemia, CSF volume depletion, hypoliquorrhoeic headache, and CSF leak headache.