Hydrocephalus or water on the brain is a health condition in which an excessive amount of cerebrospinal fluid builds up in the fluid-containing cavities of the brain. These cavities are hollow places in the cerebrum also called ventricles. The term hydrocephalus has been derived from two Greek words Hydro meaning water and Cephalus meaning head. This abnormal fluid is a liquid that surrounds the brain as well as the spinal cord. When it builds up in and around the brain, it creates undue pressure on the brain tissues, causing severe cerebral disorders. While hydrocephalus can occur at any age, it is common in infants and in people aged sixty and older. Most cases of hydrocephalus are often diagnosed during pregnancy, at the time of delivery, or in the early years of a child's life. Hydrocephalus can be inherited genetically, or it may also be a result of associated genetic ailments like spina bifida, brain injuries, brain tumor and meningitis.
Also Read: Meningitis: Causes, Symptoms And Prevention
Causes And Categories Of Hydrocephalus
The cerebrospinal fluid serves many vital functions for the brain. Not only is CSF important for delivering nutrients to the brain and removal of waste substances, but it also acts a shock absorber for the brain. Besides, it also flows between the cranium (bones that surround the brain) and the spine to maintain changes in pressure. The primary cause of accumulation of cerebrospinal fluid is either when there is an increase in production of the fluid, or when there is a constant decline in its rate of absorption. Sometimes it also happens due to an abnormality that blocks the normal flow of CSF through the ventricular system.
Broadly hydrocephalus can be divided into the following categories:
- Acquired Hydrocephalus: Primarily, caused by injury or disease, acquired hydrocephalus develops at birth or in adulthood
- Congenital Hydrocephalus: Mostly present at birth, this is a result of genetic abnormalities or also caused by events that occur during fetal development
- Communicating Hydrocephalus: This category of hydrocephalus occurs when there is no obstruction to cerebrospinal fluid within the ventricular system. The condition arises either due to an abnormal increase in the quantity of CSF produced or due to a lack of its absorption
- Obstructive Hydrocephalus: When the cerebrospinal fluid gets blocked along one or many passages that connect the ventricles, it leads to an increase in pressure inside the skull. This is called obstructive hydrocephalus
- Normal Pressure Hydrocephalus: Common in elderly individuals, this category is characterized by dilated ventricles causing abnormal pressure within the spinal column
- Hydrocephalus Ex-vacuo: Primarily affecting only adults, more often it happens when a degenerative disease, like Alzheimer’s disease, stroke, or trauma affects their brain causing shrinkage of brain substance. This is referred to as hydrocephalus ex-vacuo
Symptoms
The symptoms of hydrocephalus differ greatly from person to person and across different age groups. Infants and young children are more prone to symptoms such as
- Rapid increase in head circumference in infants
- Scalp veins that become prominent
- Downward deviation of eyes
- Nausea and vomiting
- Inflammation in the optic disc (papilledema)
- Blurred vision
- Seizures
- Urinary incontinence in adults
- Loss of balance or coordination
- Impaired cognitive skill
- Dementia
Diagnosis
Once signs and symptoms of hydrocephalus are suspected, detailed patient history and a neurological examination to assess the condition are done that may reveal useful information about the severity. The following tests are usually recommended to confirm the diagnosis and assess further treatment options:
- Computed tomography or a CAT scan
- Intracranial pressure monitoring
- Magnetic resonance imaging
- Lumbar puncturealso called spinal tap
- Isotope cisternography
Treatment
Based on the underlying etiology, hydrocephalus is treated in two primary ways. One is by directly removing the cause of obstruction of the cerebrospinal fluid and second indirectly by diverting the excess fluid. The most common way to treat this disease is by implanting a device known as a shunt that diverts the excess cerebrospinal fluid away from the brain. A shunt is a simple flexible tube consisting of a catheter and a valve. It is placed under the skin to drain unwanted fluid from a ventricle inside the brain to another body cavity such as the peritoneal cavity which is the area around the abdominal organs. Once inserted, the shunt system usually remains in its place for the entire life, continuously performing its function to divert the CSF, thus keeping the intracranial pressure in the normal range. Another way to cure this problem is endoscopic third ventriculostomy. In this surgical procedure, a surgeon utilizes the endoscope (a tiny camera) to visualize the ventricles and create an alternative path through which the cerebrospinal fluid can flow out.
