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<unk> , and because the brain is more reliant on its buoyancy in an upright position the<unk>  can be relieved by switching to a horizontal position.
Orthostatic headache
Cold-stimulus headache
External compression headache
Hypnic headache
Sexual headache
Tension headache
Thunderclap headache
Vascular headache