What are the symptoms?Symptoms of hydrocephalus vary with age, disease progression, and individual differences in tolerance to CSF. For example, an infant's ability to tolerate CSF pressure differs from an adult's. The infant skull can expand to accommodate the buildup of CSF because the sutures (the fibrous joints that connect the bones of the skull) have not yet closed.
In infancy, the most obvious indication of hydrocephalus is often the rapid increase in head circumference or an unusually large head size. Other symptoms may include vomiting, sleepiness, irritability, downward deviation of the eyes (also called "sunsetting"), and seizures.
Older children and adults may experience different symptoms because their skulls cannot expand to accommodate the buildup of CSF. In older children or adults, symptoms may include headache followed by vomiting, nausea, papilledema (swelling of the optic disk which is part of the optic nerve), blurred vision, diplopia (double vision), sunsetting of the eyes, problems with balance, poor coordination, gait disturbance, urinary incontinence, slowing or loss of development, lethargy, drowsiness, irritability, or other changes in personality or cognition including memory loss.
The symptoms described in this section account for the most typical ways in which progressive hydrocephalus manifests itself; it is, however, important to remember that symptoms vary significantly from individual to individual.
How is hydrocephalus diagnosed?Hydrocephalus is diagnosed through clinical neurological evaluation and by using cranial imaging techniques such as ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), or pressure-monitoring techniques. A physician selects the appropriate diagnostic tool based on the patient's age, clinical presentation, and the presence of known or suspected abnormalities of the brain or spinal cord.
What is the current treatment?Hydrocephalus is most often treated with the surgical placement of a shunt system. This system diverts the flow of CSF from a site within the central nervous system (CNS) to another area of the body where it can be absorbed as part of the circulatory process.
A shunt is a flexible but sturdy silastic tube. A shunt system consists of the shunt, a catheter, and a valve. One end of the catheter is placed in the CNS - most usually within a ventricle inside the brain, but also potentially within a cyst or in a site close to the spinal cord. The other end of the catheter is commonly placed within the peritoneal (abdominal) cavity, but may also be placed at other sites within the body such as a chamber of the heart or a cavity in the lung where the CSF can drain and be absorbed. A valve located along the catheter maintains one-way flow and regulates the rate of CSF flow.
A limited number of patients can be treated with an alternative procedure called third ventriculostomy. In this procedure, a neuroendoscope - a small camera designed to visualize small and difficult to reach surgical areas - allows a doctor to view the ventricular surface using fiber optic technology. The scope is guided into position so that a small hole can be made in the floor of the third ventricle, allowing the CSF to bypass the obstruction and flow toward the site of resorption around the surface of the brain.
What are the possible complications of a shunt system?Shunt systems are not perfect devices. Complications may include mechanical failure, infections, obstructions, and the need to lengthen or replace the catheter. Generally, shunt systems require monitoring and regular medical followup. When complications do occur, usually the shunt system will require some type of revision.
Some complications can lead to other problems such as overdraining or underdraining. Overdraining occurs when the shunt allows CSF to drain from the ventricles more quickly than it is produced. This overdraining can cause the ventricles to collapse, tearing blood vessels and causing headache, hemorrhage (subdural hematoma), or slit-like ventricles (slit ventricle syndrome). Underdraining occurs when CSF is not removed quickly enough and the symptoms of hydrocephalus recur (see "What are the symptoms of hydrocephalus?"). In addition to the common symptoms of hydrocephalus, infections from a shunt may also produce symptoms such as a low-grade fever, soreness of the neck or shoulder muscles, and redness or tenderness along the shunt tract. When there is reason to suspect that a shunt system is not functioning properly (for example, if the symptoms of hydrocephalus return), medical attention should be sought immediately.