Definition

Hydrocephalus is the accumulation of fluid in the ventricles or cavities of the brain. This fluid is cerebrospinal fluid, which protects the brain and spinal cord. Excess fluid enlarges the ventricles and puts pressure on the brain. Normally, cerebrospinal fluid flows through the ventricles to the space around the brain and spinal cord. Excessive fluid pressure can damage brain tissue and cause various brain function problems.

Hydrocephalus can occur at any age, but it is more common in infants and those over 60. Surgery for hydrocephalus can restore and maintain normal cerebrospinal fluid levels in the brain. Other therapies may also be needed to address symptoms or other problems caused by hydrocephalus.

Causes

An imbalance between the production and absorption of cerebrospinal fluid into the bloodstream causes hydrocephalus. Cerebrospinal fluid is produced by the tissue lining the brain ventricles and flows through channels to the space around the brain and spinal cord. This fluid is absorbed by blood vessels on the brain's surface. Cerebrospinal fluid plays a vital role in the brain by:

• Keeping the brain afloat within the skull.
• Cushioning the brain to prevent injury.
• Removing metabolic waste from the brain.
• Maintaining pressure within the brain to compensate for changes in blood pressure.

Excess cerebrospinal fluid in the ventricles can occur due to:

• Obstruction or blockage: The most common cause it can be a partial blockage between ventricles or from ventricles to other spaces around the brain.
• Poor absorption: Less common, often associated with inflammation of brain tissue from disease or injury.
• Excess production: Rare it happens when cerebrospinal fluid is produced faster than it can be absorbed.

Hydrocephalus can be congenital (present at birth) or acquired in adulthood. Causes of congenital hydrocephalus include:

• Genetic abnormalities.
• Developmental disorders of the brain, spine, or spinal cord, such as spina bifida.
• Complications of premature birth, such as bleeding in the ventricles.
• Infections during pregnancy, like mumps or rubella.

Acquired hydrocephalus may be caused by:

• Brain or spinal cord tumors.
• Infections in the central nervous system.
• Head injury or stroke causing brain bleeding.

Risk factor

medical conditions can contribute to the development of hydrocephalus. Congenital hydrocephalus, present at or soon after birth, can occur due to:

• Abnormal development of the central nervous system blocks cerebrospinal fluid flow.
• Ventricular bleeding, possibly a complication of premature birth.
• Infections in the womb, such as rubella or syphilis, cause inflammation in the fetal brain.

Other factors across all age groups include:

• Brain or spinal cord tumors.
• Central nervous system infections like bacterial meningitis.
• Brain bleeding due to stroke or head injury.
• Other traumatic brain injuries.

Symptoms

Symptoms of hydrocephalus vary by age.

Infants

Common signs and symptoms in infants include:

• Abnormally large head size.
• Rapid head size increase.
• Bulging or tense fontanel (soft spot) on top of the head.
• Nausea and vomiting.
• Drowsiness or lethargy.
• Irritability.
• Poor appetite or feeding difficulties.

Toddlers and older children

Symptoms may include:

• Headache.
• Blurred or double vision.
• Abnormally large head size in toddlers.
• Drowsiness or lethargy.
• Nausea or vomiting.
• Balance problems.
• Poor coordination.
• Personality changes.
• Declining school performance.
• Delayed or lost developmental skills, such as walking or talking.

Young and middle-aged adults

Common signs and symptoms in this age group include:

• Headache.
• Loss of coordination or balance.
• Loss of bladder control or frequent urination.
• Vision problems.
• Declining memory, concentration, and other thinking skills affecting work performance.

Older adults

Common signs and symptoms in older adults include:

• Loss of bladder control or frequent urination.
• Memory loss.
• Progressive loss of thinking or reasoning skills.
• Difficulty walking, often described as a shuffling gait.
• Poor coordination or balance.

Diagnosis

Hydrocephalus can be diagnosed through:

• Patient symptom history.
• General physical examination.
• Neurological examination.
• Brain imaging studies.

Neurological examination

The type of neurological examination depends on the patient's age. The neurologist will ask questions and conduct simple tests to assess muscle condition, movement, and sensory function.

Brain imaging

Imaging tests that help diagnose hydrocephalus and identify causes include:

• Ultrasound: Often used for initial assessment in infants as it is relatively simple and low-risk. It can also detect hydrocephalus before birth during routine pregnancy check-ups.
• Magnetic Resonance Imaging (MRI): Uses radio waves and a magnetic field to produce detailed brain images. It can show enlarged ventricles from excess cerebrospinal fluid and identify the cause of hydrocephalus or related conditions. Sedation may be needed for children, although some hospitals use rapid MRI, which usually doesn't require sedation.
• CT scan: Uses X-rays, is painless and quick. However, patients must remain still, sometimes requiring mild sedation for children. It produces less detailed images than MRI and involves small radiation exposure. CT scans for hydrocephalus are typically used only in emergencies.

Management

Two types of surgery are commonly used to treat hydrocephalus.

Shunt system placement

The most common procedure is placing a shunt system, consisting of a long, flexible tube with a valve to regulate cerebrospinal fluid flow. One end of the tube is placed in a brain ventricle, and the other is routed under the skin to another body part, such as the abdomen or heart chamber, where excess fluid can be absorbed. People with hydrocephalus usually need a shunt system for life and regular monitoring.

Endoscopic third ventriculostomy (ETV)

ETV involves creating an additional opening in the ventricle. The surgeon uses a small video camera to view the brain's interior and makes a hole in the bottom of one ventricle or between ventricles to allow cerebrospinal fluid to flow out of the brain.

Surgical complications

Both procedures can cause complications. Shunt systems may malfunction due to mechanical issues, blockages, or infections. ETV complications include bleeding and infection. Immediate medical attention, repair surgery, or other treatments are required if complications arise. If fever or initial hydrocephalus symptoms return, seek medical attention immediately.

Additional treatments

Some people with hydrocephalus, especially children, may require additional care depending on the severity of long-term complications. A care team for a child with hydrocephalus may include:

• A pediatrician to manage the treatment plan and medical care.
• A pediatric neurologist specializing in diagnosing and treating children's nervous system disorders.
• An occupational therapist to help develop daily living skills.
• A developmental therapist to help the child develop age-appropriate behavior, social skills, and interpersonal skills.
• Mental health professionals, such as psychologists or psychiatrists.
• Social workers to assist families in accessing necessary services.

Children in school may need special education teachers to address learning limitations and determine the educational needs of children with hydrocephalus. Adults with severe complications may require occupational therapy, social work services, dementia care specialists, or other medical specialists.

With rehabilitative therapy and educational interventions, many people with hydrocephalus can live with minimal limitations. There are many resources available to support the emotional and medical care of children with hydrocephalus. Children with developmental problems due to hydrocephalus may qualify for government-supported healthcare or other assistance.

Ask your doctor if you or your child should receive the meningitis vaccine, a common cause of hydrocephalus. The Centers for Disease Control and Prevention (CDC) recommends meningitis vaccination for pre-teens and a booster for teenagers. Vaccination is also recommended for children and young adults at high risk of meningitis due to:

• Traveling to countries where meningitis is common.
• Having immune system disorders.
• Damaged or removed spleen.
• Living in dormitories.
• Joining the military.

Complications

Untreated hydrocephalus can lead to complications such as intellectual, developmental, and physical disabilities, and severe hydrocephalus can be life-threatening. Timely treatment can minimize complications in less severe cases.

Babies with hydrocephalus may face future complications, including learning disabilities, speech difficulties, memory problems, organizational skill issues, vision problems like strabismus and decreased sharpness, and physical coordination problems.

Prevention

There is no known way to prevent hydrocephalus, but risks can be reduced. Ensure regular pregnancy check-ups to minimize the risk of premature birth, as premature babies are at risk of hydrocephalus.

Vaccination can prevent severe infection symptoms related to hydrocephalus. Regular check-ups and prompt treatment for illnesses or infections related to hydrocephalus are essential.

Use protective gear like helmets or seat belts to prevent head injuries in accidents. Place children in appropriate car seats when driving. Use standard-compliant baby equipment like strollers to prevent child head injuries.

When to see a doctor?

Seek medical attention immediately if an infant or toddler shows the following signs and symptoms:

• High-pitched crying
• Sucking or feeding difficulties
• Unexplained repeated vomiting
• Seizures

Promptly check for other signs or symptoms in all age groups. Multiple conditions can cause problems related to hydrocephalus, so timely diagnosis and appropriate treatment are crucial.

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