Your brain and spinal cord are bathed in a clear, circulating fluid, called cerebral spinal fluid, or CSF, which transports nutrients to brain cells, transports waste away from the cells and serves as a cushion to protect against traumatic shocks. Your brain has four interconnected cavities, or ventricles, where CSF accumulates. In some cases, however, you can accumulate too much CSF in the brain--due to a blockage between ventricles, or overproduction or underabsorption of CSF. This condition is known as hydrocephalus. Hydrocephalus is a dangerous condition that must be treated promptly.
The accumulation of too much fluid in your brain puts pressure on brain tissues. This can damage your brain cells, leading to a wide variety of symptoms. In adults, and most children, symptoms of hydrocephalus can include headache, nausea, blurred vision, loss of balance, lack of coordination, urinary incontinence, problems walking, personality changes and memory loss. This same set of symptoms, however, can occur with many other neurological disorders. The National Institutes of Health report that, "Because some of these symptoms may also be experienced in other disorders such as Alzheimer's disease, Parkinson's disease, and Creutzfeldt-Jakob disease,...hydrocephalus is often incorrectly diagnosed and never properly treated." Doctors sometimes see one unique clue, as you may experience "sunsetting," a condition in which your eyes move downward against your will.
In infants, hydrocephalus can look very different. Because the plates of a baby's skull have not yet fully fused, the skull can expand as the fluid inside it accumulates--so the most obvious sign of hydrocephalus in an infant is a sudden growth in head size, though babies can experience all of the symptoms adults experience as well.
Doctors aren't certain what causes hydrocephalus in many patients. In many cases, it may be a genetic abnormality present from birth. Some developmental disorders, like spina bifida, can lead to hydrocephalus. Traumatic head injuries, tumors or meningitis can also cause accumulation of fluid in your brain. Some brain hemorrhages can compress parts of the brain, blocking the narrow channels between the ventricles and preventing the proper flow of CSF. But, the Mayo Clinic explains, "in many cases the cause is unknown."
Doctors rely on brain scans in order to diagnose hydrocephalus. They may order a computed tomography, or CT, scan, a magnetic resonance image, MRI, or an ultrasound to see the relative size of the ventricles. In some cases, they may perform a spinal tap, or use a technique known as intracranial pressure monitoring to measure the volume and flow of CSF. There is no single tool that is always used to diagnose hydrocephalus. The NIH explains, "A physician selects the appropriate diagnostic tool based on an individual's age, clinical presentation, and the presence of known or suspected abnormalities of the brain or spinal cord."
In most cases, doctors perform surgery to treat hydrocephalus. The most common solution is to surgically insert a shunt--a long, thin piece of flexible tubing that drains CSF from one of the ventricles into a cavity in the abdomen where it is safely reabsorbed by the body. This is almost never a one-time operation. The Hydrocephalus Association explains, "Often, repeated neurosurgical operations are necessary to treat hydrocephalus." Shunts can become blocked or displaced. They are prone to infection. And children regularly outgrow their shunt, and must have a longer tube inserted. The Association notes, "50 percent of shunted individuals require a revising operation within two years," making it vital that you stay in close contact with your doctor and report any recurrence of symptoms.
Rarely, another surgical option is available. The NIH explains, "A limited number of individuals can be treated with an alternative procedure called third ventriculostomy." In this operation, doctors use a tiny camera on the end of a fiber-optic cable and microsurgical tools to cut a narrow channel out of a ventricle, bypassing an obstruction and restoring normal CSF flow. This is not always a permanent solution, either, as the channel can close over time.
Like the causes and symptoms of hydrocephalus, the outcome for patients can vary widely. The Hydrocephalus Association says "long-term health outcomes for individuals with hydrocephalus remain unpredictable. Untreated, hydrocephalus can be fatal. But, the NIH notes, "some people recover almost completely after treatment and have a good quality of life." Parents should be aware that children treated for hydrocephalus will often need rehabilitative therapy and educational accommodations, but with treatment, the NIH says, can "go on to lead normal lives with few limitations."