Hydrocephalus

Hydrocephalus is the excessive accumulation of cerebrospinal fluid in the brain’s cavities, known as ventricles. Cerebrospinal fluid is produced in the ventricles and the choroid plexuses, networks of cells and blood vessels located within these brain chambers. The fluid circulates through the brain’s ventricular system and is absorbed into the bloodstream. Through its constant movement, it surrounds and protects the brain and spinal cord, transports essential nutrients and proteins for brain function, and removes waste products from brain tissues.

If there is an imbalance between the production of cerebrospinal fluid and its absorption rate, the fluid accumulates, the ventricles expand, and intracranial pressure increases.

Hydrocephalus is classified into the following types:

• Communicating hydrocephalus: The cerebrospinal fluid flow is blocked after leaving the ventricles into the subarachnoid space. It is called "communicating" because the fluid can still flow between the ventricles.
• Non-communicating or obstructive hydrocephalus: The fluid flow is blocked at one of the pathways connecting the ventricles.
• Compensated or arrested hydrocephalus: A form of hydrocephalus that remains asymptomatic for years.
• Normal pressure hydrocephalus: The accumulation of cerebrospinal fluid causes ventricular expansion but is not accompanied by increased intracranial pressure. It usually affects adults over 60 years old.
• Ex vacuo hydrocephalus: Not a pure form of hydrocephalus, but an enlargement of the brain’s ventricular system as compensation for the loss of brain mass. This condition is usually asymptomatic and affects older adults.

The prognosis of hydrocephalus is poor without appropriate treatment, as the risk of death or disability is very high. However, when medical recommendations are followed, the disease can be largely managed.

Symptoms

Hydrocephalus symptoms vary depending on the patient’s age:

Symptoms of hydrocephalus in babies:

• Abnormal head growth.
• Bulging fontanelles: Fontanelles are the soft spots on a baby’s head where skull plates will eventually fuse.
• Severe vomiting.
• Lethargy.
• Downward deviation of the eyes.
• Irritability, high-pitched crying.
• Seizures.
• Muscle weakness.
• Feeding difficulties.

Symptoms of hydrocephalus in children:

• Headache.
• Vision problems.
• Nausea and vomiting.
• Unusual eye movements.
• Balance and coordination issues.
• Poor appetite.
• Urinary incontinence or frequent urination.
• Irritability.
• Decline in school performance.
• Delayed motor or language development.

Symptoms of hydrocephalus in young people and adults:

• Chronic headache.
• Nausea.
• Dizziness.
• Fainting.
• Vision disturbances.
• Balance and coordination problems.
• Difficulty walking.
• Short-term memory and concentration issues.

Symptoms of hydrocephalus in older adults:

• Urinary incontinence.
• Memory loss.
• Progressive cognitive impairment.
• Difficulty walking.
• Balance and coordination issues.

Causes

Hydrocephalus is classified into two types based on its origin:

Congenital hydrocephalus:

It is present at birth due to a combination of genetic and environmental factors affecting fetal development. Causes include:

• Aqueductal stenosis: The canal connecting the brain’s ventricles becomes blocked, preventing cerebrospinal fluid flow. The obstruction may result from canal narrowing, infection, hemorrhage, or a tumor.
• Myelomeningocele (spina bifida): This spinal cord and vertebral column defect blocks the outflow of cerebrospinal fluid from the fourth ventricle.
• Arachnoid cyst: These cysts typically form in the posterior brain region and near the third ventricle. They contain cerebrospinal fluid and may obstruct fluid pathways.
• Dandy-Walker syndrome: The fourth ventricle enlarges due to partial or total closure of its outlets, and part of the cerebellum fails to develop. This malformation often leads to aqueductal stenosis.
• Chiari malformation types 1 and 2: Abnormal downward displacement of part of the cerebellum due to a small or deformed skull segment causes brain tissue to extend into the spinal canal, blocking cerebrospinal fluid flow.
• X-linked hydrocephalus: A genetic disorder causing stenosis in the Sylvian aqueduct, which connects the brain’s third and fourth ventricles.

Acquired hydrocephalus:

It develops at any age after birth due to various neurological causes:

• Head trauma: Can rupture cerebral blood vessels, allowing blood to enter the cerebrospinal fluid pathways, causing inflammation and obstruction.
• Brain tumors: As they grow, tumors may block the ventricular system.
• Intraventricular hemorrhage: A rupture of ventricular blood vessels may cause blood to block the ventricles or arachnoid villi, preventing cerebrospinal fluid absorption. This primarily affects newborns.
• Meningitis: Inflammation of the brain and spinal cord membranes can damage the meninges lining cerebrospinal fluid pathways and cause blockages.

Risk Factors

The following factors contribute to hydrocephalus development:

• Infections in the uterus during pregnancy (such as rubella or syphilis) may cause fetal brain tissue inflammation.
• Premature birth, which can lead to intraventricular hemorrhage.
• Central nervous system infections, such as mumps.
• Accidents or falls causing head trauma.

Complications

Hydrocephalus is a complex disease with a highly variable prognosis. Many cases result in cognitive difficulties, visual disorders, chronic headaches, and limitations in higher brain functions. Additionally, untreated hydrocephalus is fatal.

Prevention

There are no specific preventive measures for hydrocephalus. However, proper prenatal care, infection prevention, and using protective measures while driving or engaging in risky activities can reduce risk factors.

Which Doctor Treats Hydrocephalus?

Hydrocephalus is evaluated and treated in neurology, pediatric neurology, and neurosurgery units.