Hydrocephalus

Overview

Hydrocephalus is the buildup of fluid in the cavities (ventricles) deep within the brain. The excess fluid increases the size of the ventricles and puts pressure on the brain.

Cerebrospinal fluid normally flows through the ventricles and bathes the brain and spinal column. But the pressure of too much cerebrospinal fluid associated with hydrocephalus can damage brain tissues and cause a range of brain function problems.

Hydrocephalus can happen at any age, but it occurs more frequently among infants and adults 60 and over. Surgical treatment for hydrocephalus can restore and maintain normal cerebrospinal fluid levels in the brain. Different therapies are often required to manage symptoms or problems resulting from hydrocephalus.

Symptoms

The signs and symptoms of hydrocephalus vary somewhat by age of onset.

Infants

Common signs and symptoms of hydrocephalus in infants include:

• Changes in the head
• An unusually large head
• A rapid increase in the size of the head
• A bulging or tense soft spot (fontanel) on the top of the head

Physical signs and symptoms

• Nausea and vomiting
• Sleepiness or sluggishness (lethargy)
• Irritability
• Poor eating
• Seizures
• Eyes fixed downward (sunsetting of the eyes)
• Problems with muscle tone and strength

When to see a doctor

Seek emergency medical care for infants and toddlers with these signs and symptoms:

• A high-pitched cry
• Problems with sucking or feeding
• Unexplained, recurrent vomiting
• Seizures

Causes

Hydrocephalus is caused by an imbalance between how much cerebrospinal fluid is produced and how much is absorbed into the bloodstream.

Cerebrospinal fluid is produced by tissues lining the ventricles of the brain. It flows through the ventricles by way of interconnecting channels. The fluid eventually flows into spaces around the brain and spinal column. It's absorbed primarily by blood vessels in tissues on the surface of the brain.

Cerebrospinal fluid plays an important role in brain function by:

Keeping the brain buoyant, allowing the relatively heavy brain to float within the skull

Cushioning the brain to prevent injury

Removing waste products of the brain's metabolism

Flowing back and forth between the brain cavity and spinal column to maintain a constant pressure within the brain — compensating for changes in blood pressure in the brain

Too much cerebrospinal fluid in the ventricles occurs for one of the following reasons:

Obstruction. The most common problem is a partial blockage of the flow of cerebrospinal fluid, either from one ventricle to another or from the ventricles to other spaces around the brain.

Poor absorption. Less common is a problem with absorbing cerebrospinal fluid. This is often related to inflammation of brain tissues from disease or injury.

Overproduction. Rarely, cerebrospinal fluid is created more quickly than it can be absorbed.

Risk factors

In many cases, the cause of hydrocephalus is unknown. However, a number of developmental or medical problems can contribute to or trigger hydrocephalus.

Newborns

Hydrocephalus present at birth (congenital) or shortly after birth can occur because of any of the following:

Abnormal development of the central nervous system that can obstruct the flow of cerebrospinal fluid

Bleeding within the ventricles, a possible complication of premature birth

Infection in the uterus — such as rubella or syphilis — during pregnancy, which can cause inflammation in fetal brain tissues

Other contributing factors

Other factors that can contribute to hydrocephalus among any age group include:

• Lesions or tumors of the brain or spinal cord
• Central nervous system infections, such as bacterial meningitis or mumps
• Bleeding in the brain from a stroke or head injury
• Other traumatic injury to the brain

Complications

In most cases, hydrocephalus progresses, which means complications, including intellectual, developmental and physical disabilities, can occur if it's not treated. It can also be life-threatening. Less severe cases, when treated appropriately, might have few, if any, serious complications.

Diagnosis

A diagnosis of hydrocephalus is usually based on:

Your answers to the doctor's questions about signs and symptoms

• A general physical exam
• A neurological exam
• Brain-imaging tests
• Neurological exam

The type of neurological exam will depend on a person's age. The neurologist might ask questions and conduct relatively simple tests in the office to judge muscle condition, movement, well-being and how well the senses are functioning.

Brain imaging

Imaging tests that can help diagnose hydrocephalus and identify underlying causes of the symptoms include:

Ultrasound. This test is often used for an initial assessment for infants because it's a relatively simple, low-risk procedure. The ultrasound device is placed over the soft spot (fontanel) on the top of a baby's head. Ultrasound might also detect hydrocephalus before birth during routine prenatal examinations.

MRI. This test uses radio waves and a magnetic field to produce detailed images of the brain. This test is painless, but it is noisy and requires lying still.

MRI scans can show enlarged ventricles caused by excess cerebrospinal fluid. They can also be used to identify causes of hydrocephalus or other conditions contributing to the symptoms.

Children might need mild sedation for some MRI scans. However, some hospitals use a fast version of MRI that generally doesn't require sedation.

CT scan. This specialized X-ray technology produces cross-sectional views of the brain. Scanning is painless and quick. But this test also requires lying still, so a child usually receives a mild sedative.

CT scanning produces less detailed images than MRI does and causes exposure to a small amount of radiation. CT scans for hydrocephalus are usually used only for emergency exams.

Treatment

One of two surgical treatments can be used to treat hydrocephalus.

Shunt

The most common treatment for hydrocephalus is the surgical insertion of a drainage system, called a shunt. It consists of a long, flexible tube with a valve that keeps fluid from the brain flowing in the right direction and at the proper rate.

One end of the tubing is usually placed in one of the brain's ventricles. The tubing is then tunneled under the skin to another part of the body — such as the abdomen or a heart chamber — where the excess fluid can be more easily absorbed.

People who have hydrocephalus usually need a shunt system for the rest of their lives. They require regular monitoring.

Endoscopic third ventriculostomy

Endoscopic third ventriculostomy is a surgical procedure that can be used for some people. The surgeon uses a small video camera see inside the brain. Your surgeon makes a hole in the bottom of one of the ventricles or between the ventricles to enable cerebrospinal fluid to flow out of the brain.

Complications of surgery

Both surgical procedures can result in complications. Shunt systems can stop draining cerebrospinal fluid or poorly regulate drainage because of mechanical problems, blockage or infections. Complications of ventriculostomy include bleeding and infections.

Any failure requires prompt attention, surgical revisions or other interventions. Fever or recurrence of the original symptoms of hydrocephalus should prompt an appointment with your doctor.

Other treatments

Some people with hydrocephalus, particularly children, might need additional treatment, depending on the severity of long-term complications of hydrocephalus.

Children's care teams might include the following:

Pediatrician or physiatrist, who oversees the treatment plan and medical care

Pediatric neurologist, who specializes in the diagnosis and treatment of neurological disorders in children

Occupational therapist, who specializes in therapy to develop everyday skills

Developmental therapist, who specializes in therapy to help your child develop age-appropriate behaviors, social skills and interpersonal skills

Mental health professional, such as a psychologist or psychiatrist

Social worker, who assists the family with getting needed services and planning for transitions in care

Children who are in school will likely need special education teachers, who address learning disabilities, determine educational needs and identify needed resources.

Adults with more-severe complications also might need the services of occupational therapists, social workers, specialists in dementia care or other medical specialists.