Spontaneous intracranial hypotension

A rare condition in which cerebrospinal fluidThis clear, water-like fluid forms, for the most part, within the brain, more specifically inside the ventricles of the brain. Blood flows through structures inside the ventricles, called the choroid plexuses, and clear fluid is produced as a result, passing into the ventricle. This process is akin to blood flowing through the kidneys and urine being produced as a result. An important difference is that, unlike urine, the cerebrospinal fluid is not passed out of the body periodically. Instead, the fluid is re-absorbed back into the blood stream, mostly via the arachnoid granulations, into the cerebral venous sinuses. In the course of a 24-hour period, most healthy adults will produce about 500mls (or a pint) of cerebrospinal fluid, although at... leaks, spontaneously, from the thecaThis Latin word means a sheath, or sleeve. It refers to the tube of dura that lines the spinal canal, retaining within it the spinal cerebrospinal fluid and containing the spinal cord and the nerves that issue from the cord. which lines the spinal canalThe individual bones that comprise the spinal column are made up of a weight-bearing “body” and other components which, together, form a ring of bone, behind the body. These individual vertebrae, joined together as the spinal column, therefore, create a canal running down the entire length of the spine.. The fluid that drains out of the spine and the head causes the brain to lose buoyancy. The brain slumps downwards and pulls on the arteries that supply it with blood. It also presses on the membranes that line the skull. These structures contain nerve fibres which then send pain signals to the brain itself and which are perceived as headaches. The headaches of spontaneous intracranial hypertension characteristically develop or are made worse when the affected individual is upright for a period and are relieved by lying down. In this respect they are similar to the low-pressure headaches that develop after a lumbar punctureA long needle is passed into the lower part of the spine, in order to remove some cerebrospinal fluid. This may be to reduce pressure within the head or to obtain a sample of the fluid for laboratory analysis..