Spontaneous intracranial hypotension.

Spontaneous intracranial hypotension (SIH) is caused by leakage of cerebrospinal fluid (CSF), with resultant CSF hypovolemia and intracranial hypotension. Although in some patients SIH may be preceded by minor trauma, it often occurs in the absence of any identifiable initiating event. Orthostatic headache is the primary clinical manifestation, usually accompanied by one or more other symptoms of SIH. Diagnosis can be reached by a combination of imaging studies, which may include MRI with gadolinium, nuclear cisternography, and myelography. Treatment ranges from conservative management, such as bed rest and hydration, to invasive procedures, such as lumbar puncture with autologous blood patch, CT-guided fibrin glue injection at the site of the leak, and open surgical intervention. Outcomes vary from complete resolution of CSF leak with alleviation of symptoms to continued and/or recurrent leaks with chronic unremitting symptomatology.