Primary intracranial hypotension: the syndrome of spontaneous low cerebospinal fluid pressure with traction headache.

A case of primary Intracranial Hypotension (PIH) is described. This syndrome consists of spontaneous lowering of CSF pressure with traction headache. It is a benign disorder and is self-limited. The cause is unknown, but local choroid plexus vasospasm, possibly due to a hypothalamic disturbance, has been suggested, as has leakage of CSF through spontaneous arachnoid tears. Transient symptomatic relief was achieved with 5% CO2 inhalation, apparently due to increase in cerebral blood flow.