WHAT IS HYDROCEPHALUS?
The term hydrocephalus is derived from two words: “hydro” meaning water, and “cephalus” referring to the head.
Hydrocephalus is a condition in which excess cerebrospinal fluid (CSF) builds up within the ventricles (fluid-containing cavities) of the brain and may increase pressure within the head.
Although hydrocephalus is often described as “water on the brain,” the “water” is actually CSF, a clear fluid surrounding the brain and spinal cord. CSF has three crucial functions: 1) it acts as a “shock absorber” for the brain and spinal cord; 2) it acts as a vehicle for delivering nutrients to the brain and removing waste; and 3) it flows between the cranium and spine to regulate changes in pressure within the brain.
Hydrocephalus can occur at any age, but is most commonly diagnosed in infants and elderly adults (age 60 or older). You may be a parent of an infant who is born with this condition, you may be the son or daughter of a parent with hydrocephalus, or you may yourself have been referred for evaluation of hydrocephalus. According to the National Institute of Neurological Disorders and Stroke, hydrocephalus is believed to affect approximately one in every 500 children. The majority of these cases are often diagnosed before birth, at the time of delivery, or in early childhood.
COMMON CAUSES OF HYDROCEPHALUS
Although rare, hydrocephalus can be inherited genetically or may be associated with developmental disorders, including spina bifida (congenital defect of the spine) and encephalocele (hernia of the brain). Other causes can include bleeding within the brain, brain tumors, head injuries, complications of premature birth such as hemorrhage, or diseases such as meningitis or other infections. In some cases, normal flow of CSF within the brain is blocked, resulting in fluid build-up.
Symptoms of hydrocephalus vary significantly from individual to individual. According to the Hydrocephalus Association, some of the most common symptoms are listed below as a reference.
Symptoms of Hydrocephalus in INFANTS
Abnormal enlargement of the head; soft spot (fontanel) is tense and bulging; scalp can appear thin; bones separated in baby’s head; prominent scalp veins; vomiting; drowsiness; irritability; downward deviation of baby’s eyes; seizures; or poor appetite.
Symptoms of Hydrocephalus in TODDLERS/CHILDREN
Abnormal enlargement of baby’s head; headache; nausea; vomiting; fever; blurred or double vision; unstable balance; irritability; sleepiness; delayed progress in walking or talking; poor coordination; change in personality; inability to concentrate; loss of sensory motor functions; seizures; or poor appetite. Older children may experience difficulty in remaining awake or waking up.
Symptoms of Hydrocephalus in YOUNG and MIDDLE-AGED ADULTS
Headache; difficulty in remaining awake or waking up; loss of coordination or balance; bladder control problems; impaired vision and cognitive skills that may affect job performance and personal skills. Symptoms of Hydrocephalus in ELDERLY ADULTS Loss of coordination or balance; memory loss; headache; or bladder control problems.
Hydrocephalus is often categorized for age groups as either congenital or normal pressure hydrocephalus. Congenital hydrocephalus refers to conditions that are caused by conditions existing at birth. Main symptoms include headache, nausea, vomiting and drowsiness (refer to symptoms of Infants/Toddlers/Children). Normal pressure hydrocephalus is the accumulation of cerebrospinal fluid that causes the ventricles in the brain to become enlarged, with little or no increase in pressure. Adult-onset normal pressure hydrocephalus mainly occurs in relatively older adults (age 60 years or older).
Before your doctor can recommend a course of treatment, he or she will:
- review the medical history, and perform a physical examination
- perform a complete neurological examination including diagnostic testing if needed
- ask specific questions to determine if symptoms are caused by hydrocephalus
The neurological examination will also help to determine the severity of the condition. Further tests such as an ultrasound (if the patient is an infant), computed tomography (CT) scan, or magnetic resonance imaging (MRI) may be ordered.
The tests may reveal useful information about the severity of the condition and its likely cause.
WHEN SURGERY IS NECESSARY
Hydrocephalus can be treated in a variety of ways. The problem area may be treated directly (by removing the cause of CSF obstruction), or indirectly (by diverting the fluid to somewhere else, typically to another body cavity). Indirect treatment is performed by implanting a device known as a shunt to divert the excess CSF away from the brain. The body cavity in which the CSF is diverted is usually the peritoneal cavity (the area surrounding the abdominal organs). In some cases, two procedures are performed, one to divert the CSF, and another at a later stage to remove the cause of obstruction (e.g., a brain tumor). Once inserted, the shunt system usually remains in place for the duration of a patient’s life (although additional operations to revise the shunt system are sometimes necessary). The shunt system will continuously perform its function of diverting the CSF away from the brain, thereby keeping the intracranial pressure within normal limits.
The shunt (a tube) is implanted through a surgical procedure. A general anesthetic is commonly administered for the procedure. The shunt tubing is tunneled into the brain through a small hole drilled in the skull. The other end of the shunt tubing is then inserted beneath the skin of the head, neck and chest and threaded into another body cavity or organ (peritoneal cavity, heart, chest, etc.) into which the CSF is drained and subsequently safely absorbed. In order to properly regulate the amount of CSF being drained, an in-line valve is included as part of the shunt system. This valve allows CSF flow in a single direction only (away from the brain). One of several different valve systems will be selected by the surgeon depending on the patient’s specific needs. It is important to note that shunting is only a method for managing hydrocephalus, and is not a cure. However, the majority of patients with hydrocephalus will have improvements in symptoms after shunting.
A programmable shunt system is commonly used in treatment for elderly patients with normal pressure hydrocephalus. The implantation of a programmable valve allows the neurosurgeon to adjust the pressure of the valve with a special non-invasive device. This in turn affects CSF flow through the shunt.
After surgery, the shunt system is completely inside the body. Antibiotics are often prescribed for a short time to reduce the risk of infection.
For some patient’s including those children with obstructive hydrocephalus, the surgeon may recommend an operation called endoscopic third ventriculostomy. In this operation, the surgeon uses a miniaturized camera to look inside the ventricles. By making a small opening through a membrane near the bottom of the brain, the surgeon creates a new pathway through which CSF can flow. These patients typically do not need a shunt after surgery. Risks of this operation include a slightly higher change of major bleeding from an arterial injury and the chance that the opening, which the surgeon creates, may gradually close off over time. Many neurosurgeons do not perform endoscopic third ventriculostomy on children under the age of two years, because the failure rate or that age is estimated higher than for older children.
Certain risks must be considered with any surgery. Your surgeon will take every precaution to avoid complications, however the most common risks of shunt surgeries are infection, malfunction of the shunt, disconnection of the shunt, or obstruction.
Other possible risks include hemorrhage (excessive bleeding) within the brain. Although complications are rare, prior to surgery you should discuss with your doctor any risks associated with the procedure. These complications require additional surgery to correct the problem.
Without any surgical treatment however, the patient may suffer considerable damage from increased pressure within the brain and compression of vital brain tissues. Treatment of patients with hydrocephalus can save and sustain healthy lives.
RECOVERY AFTER SURGERY
After surgery, the patient is carefully observed in the hospital by specially trained medical professionals. Some symptoms, such as headaches, may disappear immediately due to the release of excess pressure.
Generally, the patient is encouraged to become more active, and a gradual return to normal activity is encouraged. The length of the patient’s hospital stay will be determined by his or her rate of recovery and availability of ongoing care at home. By the time the patient is scheduled for a postoperative visit, he or she may notice some further improvements in health, and incisions may become less sore. At the postoperative visit, your surgeon will remove skin staples or sutures (stitches) and will examine the incision.
Your doctor may also evaluate neurological function. If a neurological problem persists, rehabilitation may be required to further the patient’s improvement. However, recovery may be limited by the extent of the damage already caused by the hydrocephalus and by the brain’s ability to heal.
Because hydrocephalus is an ongoing condition, patients do require long-term follow up care by a doctor. Follow-up diagnostic tests including CT scans, MRIs and x-rays may be performed to determine if the shunt is working correctly. Do not hesitate to contact your physician if you experience any of the following postoperative symptoms:
- Redness, tenderness, pain or swelling of the skin along the length of the tube or incision
- Irritability or drowsiness
- Nausea, vomiting, headache or double vision
- Abdominal pain
- Return of preoperative neurological symptoms
For adult patients, your doctor will help to determine when you can return to work and with what limitations. Driving a motor vehicle will be possible once your doctor acknowledges that you have recovered full coordination, you are experiencing minimal pain, and you are no longer taking medications which may impair your ability to drive.