Spontaneous intracranial hypotension: dilemmas in diagnosis.

Intracranial hypotension is not an uncommon diagnosis after lumbar puncture or neurosurgery. However, spontaneous intracranial hypotension (SIH) is a poorly understood entity that can present with a wide variety of symptoms/signs ranging from headache to coma. SIH may result from an occult spinal cerebrospinal fluid (CSF) leak. Alternatively, because a CSF leak is not always found, some posit that SIH is caused by venous hypotension that results in increased CSF absorption. The true incidence of SIH is unknown and the diagnosis is frequently missed given the wide range of presenting symptoms and imaging findings that are mistaken for other diagnoses (ie, subdural hematomas, Chiari malformation). Here, based on a comprehensive literature review, we describe the epidemiology, presentation, diagnostic workup and treatment of SIH.