A headache that vanishes when you lie down can signal leaking brain fluid
The brain floats in cerebrospinal fluid held inside a tough membrane called the dura. When that membrane springs a hole, fluid drains away and the brain sags. The telltale sign is a headache that worsens on standing and eases when lying flat, sometimes so severe that sufferers cannot stay upright.
Most leaks happen along the spine, not in the head. A spinal leak lowers the volume of fluid around the brain, a state called spontaneous intracranial hypotension, although pressure readings can be normal and the real problem is simply too little fluid. Cranial leaks are rarer and behave differently: they often cause clear fluid to drip from one nostril or an ear, can leave a metallic taste, and are usually driven by high pressure inside the skull rupturing the dura.
Spontaneous leaks affect at least one person in 20,000, with many more going undiagnosed. The average age of onset is 42, and women are affected twice as often as men. A frequent culprit is a tiny calcified bony spur near a spinal disc that pierces the dura like a blade, leaving a slit a few millimetres long. Up to two thirds of patients show signs of a connective tissue disorder such as Marfan or Ehlers-Danlos syndrome. Leaks can also follow lumbar punctures, spinal surgery or head injury.
The symptom list is long and easily misread: neck stiffness, nausea, dizziness, ringing or muffled hearing, brain fog and fatigue. Low fluid can let the cerebellum drop in a way that mimics a Chiari malformation, and chronic cases can even resemble frontotemporal dementia, with personality changes that reverse once the leak is sealed. Cranial leaks carry a 10 percent yearly risk of meningitis, whereas spinal leak sites are sterile and cannot cause it.
Locating the hole usually takes CT myelography. Repairs include an epidural blood patch, in which the patient's own blood is injected at the site, fibrin glue, or surgery, and some chronic leaks persist despite repeated patching. German neurologist Georg Schaltenbrand described the symptoms in 1938, and Henry Woltman of the Mayo Clinic followed in the 1950s.
Source: Cerebrospinal fluid leak
