Spontaneous Intracranial Hypotension

This chapter evaluates spontaneous intracranial hypotension (SIH), which is a well-recognized syndrome that is characterized by orthostatic headaches in association with a variety of other symptoms. It results from an occult leakage of cerebrospinal fluid (CSF) through weakness of the dura from nerve root sleeves, dural rents caused by herniated discs or osteophytic microspurs, or by CSF-venous fistulas. In the majority of cases, the cause of SIH is unclear, but possible precipitants include a history of trivial trauma and weakness of the dural sac. The characteristic clinical feature of SIH is headache, which is usually throbbing, bilateral, and worsened by Valsalva maneuvers. The diagnosis of SIH may be established in several ways, but there is not a single modality that consistently reveals the answer. Treatment of SIH includes conservative measures such as bed rest and hydration and caffeine administration (by mouth or intravenously). Epidural blood patching may provide relief.