Neurological Symptoms of Intracranial Hypotension

ABSTRACT

Intracranial hypotension usually arises in the context of known or suspected leak of cerebrospinal fluid (CSF). This leakage leads to a fall in intracranial CSF pressure and CSF volume. The most common clinical manifestation of intracranial hypotension is orthostatic headache. Post-dural puncture headache and CSF fistula headache are classified along with headache attributed to spontaneous intracranial hypotension as headache attributed to low CSF pressure by the International Classification of Headache Disorders. Headache attributed to low CSF pressure is usually but not always orthostatic. The orthostatic features at its onset can become less prominent over time. Other manifestations of intracranial hypotension are nausea, spine pain, neck stiffness, photophobia, hearing abnormalities, tinnitus, dizziness, gait unsteadiness, cognitive and mental status changes, movement disorders and upper extremity radicular symptoms. There are two presumed pathophysiologic mechanisms behind the development of various manifestations of intracranial hypotension. Firstly, CSF loss leads to downward shift of the brain causing traction on the anchoring and supporting structures of the brain. Secondly, CSF loss results in compensatory meningeal venodilation. Headaches presenting acutely after an intervention or trauma that is known to cause CSF leakage are easy to diagnose. However, a high degree of suspicion is required to make the diagnosis of spontaneous intracranial hypotension and understanding various neurological symptoms of intracranial hypotension may help clinicians.