Pressure-dissociation headache

A specific type of headache that develops because the normal free communication of 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..., across the craniovertebral junctionThat part of the body where the base of the skull is joined to the top of the spine. Inside these bony enclosures, the craniovertebral junction is also where the brain stem continues downwards as the spinal cord., is partially obstructed. Normally, during coughing, sneezing, laughing, straining, bending over or similar Valsalva-like activities, 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... is squeezed from 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. into the cranial cavity, only to then return once the action ceases. In the presence of herniated cerebellar tonsilsThe lower-most part of the cerebellum is made up of a pair of structures, one on each side of the midline, known as the tonsils. These structures have no relationship with the tissue at the back of the throat, which becomes inflamed and sore with a viral infection. It is simply the case that the same Latin term was applied by (presumably) different anatomists, at different times and working in different places, to name these very different body parts. The word tonsilla literally means a stump; Roman ships were moored to “tonsilla” when in port. (otherwise referred to as a hindbrain herniaAn alternative term for a Chiari malformation. It is better than the eponymous term because it is in many ways more descriptive of the anatomical abnormality., or Chiari malformationAn anatomical abnormality affecting the lowermost part of brain, where it joins the spinal cord, at the top of the neck. Various sub-types are described - see under their individual names. The term hindbrain hernia is sometimes used to incorporate all forms.), a valve mechanism operates, such that the 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... can pass readily into the head but returns only very slowly. The individual has, in effect, injected a volume of her or his 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... – a normal body constituent – into the head, thereby transiently increasing the intracranial pressureThis is the effective pressure within the tissues inside the skull, principally the brain. In any organ of the body blood flows in through arteries, passes through a capillary bed and drains back out into veins. Blood will spurt out of a cut artery under high pressure. Blood will flow out of a vein under low pressure. Between these inflow and outflow channels the pressure averages at a level which, in effect, represents what is left of the main arterial pressure, as it dissipates through the brain’s capillary bed. If the brain’s venous drainage reduces, for example when lying down from a standing position, then the intracranial pressure will rise. Following brain surgery, therefore, patients are often nursed in a... and generating a short-lived but intense headache. This may be generalised in distribution but is often worse in the occipitalThis term simply refers to the back of the head. The occipital lobes of the brain are at the back of the brain – one lobe of each side of the midline. region.