Orthostatic headache

Orthostatic headache is a medical condition in which a person develops a headache while vertical and the headache is relieved when horizontal. Previously it was often misdiagnosed as different primary headache disorders such as migraine or tension headaches. Increasing awareness of the symptom and its causes has prevented delayed or missed diagnosis.

The most common cause of orthostatic headache is low cerebrospinal fluid pressure, due to a spontaneous cerebrospinal fluid leak, a traumatic cerebrospinal fluid leak, or a post-dural-puncture leak. It is also occasionally the most prominent symptom of postural orthostatic tachycardia syndrome (POTS). Distinguishing POTS from a cerebrospinal fluid leak can be difficult, because the defining symptom of POTS, positional tachycardia, also occurs in some people with cerebrospinal fluid leaks. Furthermore, both POTS and cerebrospinal fluid leaks are sometimes present in the same person, especially in people with Ehlers–Danlos syndrome.

Other causes include colloid cysts and possibly connective tissue disorders. It may occur as a complication of decompressive surgery for Chiari malformation or decompressive craniectomies for cerebral edema.

Cerebrospinal Fluid (CSF) Leak causes loss of CSF volume around the brain. This causes the brain to lose its buoyancy, which results in pressure on pain-sensitive areas like the dura and blood vessels. The pain is what results in a headache, and because the brain is more reliant on its buoyancy in an upright position the headache can be relieved by switching to a horizontal position.

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