Life-Threatening Complications of Hydrocephalus
Hydrocephalus is almost always treated successfully with surgical placement of a shunt or an ETV; but rarely does either treatment last a lifetime without complications. A critical aspect of managing hydrocephalus is being well informed and staying vigilant about potential life-threatening complications. Most problems associated with shunting or ETV occur weeks or even years after the surgery. When things are going well, it is easy to forget about hydrocephalus and having a shunt or an ETV. We encourage you to stay alert and informed. Feel free to call or email the Hydrocephalus Association for more information about any of the complications listed here.
Knowing what symptoms to watch for will help you become more at ease. Although the early symptoms of shunt malfunction or infection in children—fever, vomiting and irritability—are similar to many childhood illnesses, you will learn to determine the symptoms associated with shunt failure in a particular individual. Adults tend to exhibit the symptoms they experienced before treatment when there is a problem. If you have any doubt about symptoms, don’t hesitate to contact a doctor. If you suspect there is a problem with the shunt, you are wise to have it checked by the neurosurgeon rather than ignore it. It is better to have a false alarm checked than to leave it unattended. Remember, although shunt complications can be very serious and become life threatening, they can almost always be treated successfully when they are discovered early.
An estimated 50% of shunts fail within two years and 20-50% of ETVs close up within five years. Either treatment can fail at any time. Infections are less common, but still not infrequent. Be informed and vigilant. Be prepared to act quickly. Mere hours can mean the difference between a resolvable complication and brain damage or even death, especially in children.
Shunt malfunction is usually a problem with a partial or complete blockage of the shunt. The fluid backs up from the site of the obstruction and, if the blockage is not corrected, almost always results in recurrent symptoms of hydrocephalus. Shunt obstruction can occur in any part of the shunt. Most commonly in children, the ventricular catheter (the one in the brain) becomes obstructed by tissue from the choroid plexus or ventricles. In adults it is more often the distal catheter (the one that drains the fluid to another part of the body) that becomes blocked. The catheters or the valve may become blocked with blood cells or bacteria. Shunts are very durable, but the components of the shunt can become disengaged or fractured as a result of wear or as a child grows, and occasionally they move from where they originally were placed. More rarely, a valve will fail because of mechanical malfunction.
Shunt infection usually is caused by a person’s own bacterial organisms; it is not acquired from exposure to other children or adults who are ill. The most common organism to produce infection is Staphylococcus Epidermidis, which is normally found on the surface of the person’s skin and in the sweat glands and hair follicles deep within the skin. Infections of this type are most likely to occur one to three months after surgery but may occur up to six months after the placement of a shunt. People with ventriculo-peritoneal (VP) shunts are at risk of developing a shunt infection secondary to abdominal infection, whereas people with ventriculo-atrial (VA) shunts may develop generalized infection, which can quickly become serious. In either case, the shunt infection must be treated immediately to avoid life-threatening illness or possible brain damage.
Other Shunt Complications may include the shunt system draining fluid at the wrong rate. Overdrainage of the ventricles can cause the ventricle to decrease in size to the point where the brain and its meninges pull away from the skull or the ventricles become like slits. If blood from broken vessels in the meninges becomes trapped between the brain and skull, resulting in a subdural hematoma, further surgery is required. This is most common in older adults with normal pressure hydrocephalus (NPH). Slit-like ventricles, sometimes called slit-ventricle syndrome (SVS), are most commonly a problem in young adults who have been shunted since childhood. Underdrainage of the ventricles can fail to relieve the symptoms of hydrocephalus. To restore a balanced flow of CSF it may be necessary to place a new shunt containing a more appropriate pressure valve. For those who have externally adjustable or programmable valves, the balance of flow can often be restored by re-setting the opening pressure.
When the ventricles get too small, usually due to too much fluid drainage over time, they become like slits. This only tends to happen in those shunted since early childhood and can manifest either in childhood or young adulthood. Symptoms include severe intermittent headaches, characteristically lasting 10-90 minutes that are often relieved when lying down, and smaller than normal ventricles on imaging studies. Some doctors refer to this as slit ventricle syndrome (SVS). Patients may be asymptomatic for prolonged periods. Most often the condition responds to intervention and most shunt manufacturers have shunt hardware designed to address the problem.
The term “multiloculated hydrocephalus” refers to the presence of an isolated CSF compartment or compartments within the ventricular system that may become enlarged despite a functioning shunt. It is most often caused by birth trauma, neonatal intraventricular hemorrhage, ventriculitis, shunt related infection or overdrainage. Because the condition is usually in infants and children who are already neurologically compromised, it can be difficult to recognize. Among several of the operative treatments are multiple shunt placement, multiperforated ventricular catheters, craniotomy and fenestration of intraventricular septations.
Seizures and Hydrocephalus:
Seizures are not an uncommon occurrence in people with hydrocephalus. However, no correlations have been found between the number of shunt revisions or the site of shunt placement and the risk of developing seizures. Past studies have shown:
- Children who have been shunted for hydrocephalus and who have significant cognitive delay or motor disability are more likely to develop seizures than those without cognitive or motor delays.
- Seizures are not likely to occur at the time of shunt malfunction.
- The most likely explanation for the development of seizure disorder is the presence of associated malformations of the cerebral cortex.
The peritoneum (belly area) is the most popular site for the distal catheter implantation. Although ventriculo- peritoneal (VP) shunts do not have fewer complications than ventriculo-atrial shunts, the complications are less severe and associated with a lower mortality rate. However the peritoneum is not immune to specific complications. Abdominal problems represent a good number of VP shunt complications including peritoneal pseudocysts, lost distal catheters, bowel perforations and hernias that require special attention.
Symptoms of shunt malfunction vary considerably from person to person, but tend to be similar each time for a particular person. Often the symptoms that existed before treatment return when something is going wrong.
In infants, signs include a full and tense fontanel (soft spot), bulging of the scalp veins and swelling or redness along the shunt tract. Also watch for symptoms like unusual vomiting, irritability, sleepiness and decreased interest in eating. Be aware that medication with a side effect of drowsiness can mimic or mask signs of shunt malfunction and should be used with caution in those with hydrocephalus, especially infants and young children.
When the child is older and the fontanel and other sutures between the skull bones are closed, you no longer have the same warning signs. Children and adults may experience headaches, vomiting, irritability and tiredness. Swelling along the shunt tract occurs less frequently. In the event of an abrupt malfunction, a child may develop symptoms very rapidly, in a matter of hours or days. Without treatment, coma, and even death, may result.
Older children and young adults may also become increasingly tired, have difficulty waking up and staying awake, experience personality changes and, unless treated promptly, may go into a coma.
People who were diagnosed and treated in adulthood, including those with NPH, tend to revert to the symptoms they experienced before initial treatment during a malfunction.
Sudden closure of ETV:
While there are a number of reports that describe the benefits following ETV, there are others that raise concerns that the pathway created for CSF flow can close up. It can be sudden and life-threatening. It is critical that parents and patients understand that ETV is not a cure for hydrocephalus. Be alert to signs and symptoms that may signal failure of the ETV, which are similar to those described for shunt malfunction. Neurosurgeons should keep a watchful eye on their ETV patients just as they do with their shunted patients.
Shunt infection frequently results in fever and may happen with or without a shunt obstruction. Sometimes shunt infection also produces reddening or swelling along the shunt tract. If an infection is suspected it is critical to notify the neurosurgeon immediately or go to the emergency room. A shunt infection must be treated immediately to avoid life-threatening illness or possible brain damage.