treated with Abnormal Nervous System Physiology Intracranial Hypotension DOID:4723 Generally, there are no localising symptoms forms directly from the leak, as CSF is absorbed into tissues. The condition often presents as a positional headache which is relieved by a recumbent position, usually within 15-30min. It is confirmed by assessing opening pressure on LP (less than 7 cm CSF). Note that when this is done fluoroscopically, it should be performed in a lateral position to allow for accurate measurement of pressure. Occasionally presentation is more sinister, with even decreased level of consciousness and coma reported. Suggest update to description Suggest update to description in DOID (currently no description) CSF pressure less than 6 cm of H2O in patients with clinical presentation compatible with intracranial hypotension, which are postural headache, nausea, vomiting, neck pain, visual and hearing disturbances, and vertigo. It most commonly results from CSF leaks somewhere along the neuraxis. Spontaneous intracranial hypotension is typically encountered in middle age (30-50 years of age) and has a predilection for women (F:M 2:1). Of interest, this is a similar demographic to pseudotumour cerebri, which is believed to be an unrecognised predisposing factor. Epidemiology of secondary intracranial hypotension is variable and matches that of the underlying cause. Craniospinal Hypotension Intracranial hypotension can broadly be divided into: 1.Primary: usually referred to as spontaneous intracranial hypotension. 2. Secondary: iatrogenic (LP or surgery), over shunting due to diversion devices or traumatic. Decreased Intracranial Pressure Surgery