Hydrocephalus

Our multidisciplinary team approach to treating hydrocephalus is highly-trained, and all our neurologists and neurosurgeons are board-certified in their respective fields. Many of our patients come to The Department of Neurosurgery at Rutgers Health and RWJBarnabas Health for a second opinion or for better care than they may have access to, locally. We encourage you to reach out to us if you or a loved one is suffering from hydrocephalus.

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What Is Hydrocephalus?

Hydrocephalus is a chronic neurological condition, formerly called “water on the brain.” While it cannot be cured, it is treatable. Hydrocephalus is a result of overaccumulation of cerebrospinal fluid (CSF) in the brain. CSF is responsible for cushioning the brain, keeping the brain buoyant, removing waste products, and more. It flows through and bathes the cavities (ventricles) of the brain and spinal cord, protecting them from injury. When the flow of CSF becomes blocked, the fluid builds up and causes the ventricles to enlarge, and pressure inside the head increases inside the skull. Hydrocephalus can cause permanent function impairment or brain damage. This condition affects at least 1 million Americans, according to The Hydrocephalus Association, and can happen at any age, including infancy. Early diagnosis and treatment of hydrocephalus is critical for a good recovery.

Seek emergency medical treatment for your infant or toddler if you suspect they have hydrocephalus symptoms. Prompt treatment is important for optimal outcomes.

Types of Hydrocephalus and Associated Symptoms

  • Normal pressure hydrocephalus (NPH): Seen in older adults over the age of 60, NPH has 3 classic symptoms, including difficulty walking, dementia, and incontinence. Because symptoms are similar to Alzheimer’s or Parkinson’s disease, and some may consider the symptoms natural from the aging process, it can be difficult to diagnose. The exact cause of NPH is not clear, and in most patients, it is “idiopathic,” meaning of unknown origin. However, NPH can also occur because of other conditions affecting the brain, such as stroke, or a meningitis infection.
  • Acquired hydrocephalus: This form of hydrocephalus is “acquired” because it is not present at birth. It develops most often because of head injuries, brain tumors, intraventricular hemorrhage, meningitis, or any infection of the brain or spinal cord.
  • Congenital hydrocephalus: This condition is present at birth, and often evident on prenatal ultrasounds before the baby is born. It is most commonly caused by spina bifida, aqueductal stenosis, or brain malformations. Infants with hydrocephalus have an abnormally large head, and may experience additional symptoms, such as vomiting and lethargy. Congenital hydrocephalus may be caused by the abnormal development of the central nervous system, bleeding in the ventricles, or an intrauterine infection of the mother which causes the fetal brain tissues to become inflamed.

Symptoms by Age Group

  • Infants: Newborns and young children typically have an abnormally large head, a bulging soft spot, prominent scalp veins, vomiting, sleepiness, headache, nausea, and downward deviation of the eyes (“sunset eyes”).
  • Adults: Young and middle-aged adults experience chronic headaches, difficulty walking, cognitive challenges, and incontinence.
  • Older Adults (NPH): Adults, typically over the age of 60, experience difficulty walking, gait disturbances, mild dementia, and incontinence.

Causes of Hydrocephalus

The causes of hydrocephalus are not well understood, but it is thought to result from the complex interaction of environmental and/or genetic factors.

Common Causes of Congenital Hydrocephalus

When hydrocephalus is present at birth, it is called “congenital” hydrocephalus. It is believed to occur in about 2 out of every 1,000 births.

The main types of congenital hydrocephalus include:

  • Aqueductal stenosis: This is the most common cause of hydrocephalus at birth, and it occurs when two ventricles of the brain become narrowed or blocked. This may happen as a result of infection, hemorrhage, or a tumor.
  • Neural tube defect: Known as spina bifida (Latin for “split spine”), neural tube defects are obvious when a baby is born, because there is a protruding sac from the lower back, exposing the spinal cord.
  • Primary arachnoid cysts: These may develop anywhere in the brain but are most often located in the back of the brain, or in the third ventricle, in the early weeks of gestation. Fluid becomes trapped by CSF-filled cysts, causing hydrocephalus.
  • Dandy-Walker syndrome: This congenital brain malformation is caused by the fourth ventricle enlarging in the back of the brain (cerebellum). The increase in size may cause hydrocephalus.
  • Chiari malformation: These structural defects occur in the base of the skull and cerebellum, when part of the cerebellum extends through the base of the skull, and the resulting pressure blocks CSF flow, causing increased pressure on tissue and nerves.

Common Causes of Acquired Hydrocephalus

Acquired hydrocephalus is not present at birth, but develops later in life, usually from head injury, infection, brain bleeds, or brain tumors, but many incidences of adult-onset hydrocephalus and acquired hydrocephalus are unknown.

The main types of acquired hydrocephalus include:

  • Meningitis: This infection of the membranes of the brain and spinal cord is caused by a bacterial infection. It scars the delicate membranes lining the CSF pathway.
  • Head trauma: If a head injury damages the brain tissue, nerves or blood vessels, it can cause inflammation and CSF absorption sites may become blocked or scarred. If CSF flow is restricted, it causes hydrocephalus.
  • Brain tumors: As a brain tumor grows, it can block CSF flow and cause hydrocephalus. The most common brain tumor type to cause hydrocephalus occurs in the back of the brain, referred to as the posterior fossa.

Hydrocephalus Prevention

Although hydrocephalus cannot be prevented, there are ways to possibly reduce the risks. For example, pregnant women must keep their regular, recommended appointments to reduce the risk of premature birth.

Diagnosis of Hydrocephalus

Hydrocephalus is a condition, not a disease, meaning a physician must determine the cause of hydrocephalus in order to treat it. Usually hydrocephalus is easier to diagnose and more readily apparent in infants, as the baby’s head is typically abnormally large. Hydrocephalus may even be diagnosed prior to birth, if an ultrasound detects the condition during routine prenatal appointments.

The following may be useful in diagnosing hydrocephalus:

  • Clinical exam: A neurologist will interview the patient or the patient’s parent(s) about their symptoms and take a medical history. This also includes a neurological exam and neuropsychological testing.
  • Brain imaging tests: A computed tomography (CT) scan or magnetic resonance imaging (MRI) scan are used to look for enlarged brain ventricles. CT scans utilize specialized X-ray technology to produce a cross-sectional view of the brain. Infants and young children may need to be sedated for brain imaging tests, as it is necessary to lie still to get accurate images.

Hydrocephalus Treatment

Surgical treatment is necessary to treat hydrocephalus, usually through the surgical placement of a shunt. Shunts are the most common treatment and involve surgical insertion of a flexible tube placed in the ventricular system of the brain, which serves to drain the excess fluid. The shunt diverts CSF flow to other regions of the body, such as the abdominal cavity or the heart, where it can be properly absorbed. A limited number of patients may be treated by endoscopic third ventriculostomy (ETV). This procedure is done by puncturing a membrane of the third ventricle. This creates a pathway for the excess fluid on the brain to flow within the other cavities of the brain.

Risks of Hydrocephalus Surgery

Any surgery has risks, and hydrocephalus surgery is no exception. The common risks of surgery include bleeding, infection, and adverse anesthesia reactions. Patients may also experience shunt malfunction or infection, as well as subdural hematoma.

If you suspect you or your baby has an infection, you must immediately notify your neurosurgeon or call 9-1-1 for transportation to the nearest emergency room. Shunt infections are extremely serious and can be life-threatening or cause brain damage.

  • Shunt infection: Infections generally appear one to six months after the placement of a shunt. These infections can quickly become serious, even to the point of causing permanent brain damage.
  • Shunt malfunction: If the shunt becomes partially or completely blocked, CSF cannot drain. This is an uncommon complication, because shunts are very durable. However, their components may become fractured through wear, or as a child grows.
  • Subdural hematoma: A blood clot following a shunt insertion is a very serious complication, occurring in about 5-10% of patients, according to The Hydrocephalus Association.

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