Definition

Hydrocephalus is a condition in which too much fluid builds up in the brain. The fluid is called cerebrospinal fluid (CSF). It is a clear liquid that normally surrounds both the spinal cord and the brain.

Hydrocephalus

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Hydrocephalus occurs when:

• An excess of CSF is produced (rare)
• A blockage that doesn't allow CSF to drain properly (more commonly)

Hydrocephalus can be:

• Congenital—you are born with the condition
• Acquired—you suffer an injury or an illness that causes the condition to develop

Causes

Causes include:

• Brain tumors
• Cancer in the cerebrospinal fluid (CSF)
• Inflammation in the CSF (such as sarcoidosis)
• Cysts in the brain
• Malformations of the brain, such as:
  • Dandy-Walker syndrome
  • Arnold-Chiari malformation
  • Spina bifida
• Brain injuries
• Infections of the brain or the meninges can be caused by a number of agents including bacteria, mycobacteria, fungus, viruses, and parasites, such as:
  • Encephalitis—inflammation of the brain
  • Meningitis—inflammation of the membranes that cover the brain and spinal cord
• Blood vessel abnormalities in the brain
• Bleeding into the brain

Risk Factors

Risk factors for hydrocephalus include:

• Neural tube defects
• Mother has infection during pregnancy, such as:
  • Cytomegalovirus
  • Toxoplasmosis
  • Lymphocytic choriomeningitis virus
  • Chickenpox
  • Mumps
• Brain infections
• Malformations of the brain
• Brain injuries

Symptoms

Symptoms depend on the severity of the hydrocephalus. The CSF puts pressure on structures within the brain. Symptoms may start out mild and become more severe as CSF pressure increases.

Symptoms may include:

• Headache (often worse when lying down or upon first awakening in the morning)
• Nausea / Vomiting
• Problems with balance
• Difficulty walking
• Poor coordination
• Incontinence
• Personality changes
• Confusion
• Memory problems
• Dementia in the elderly
• Coma and death
• In babies:
  • Slow development
  • Loss of developmental milestones
  • Bulging fontanelle (soft spot on the head)
  • Large head circumference

Diagnosis

The doctor will ask about your symptoms and medical history. A physical exam will be done.

Tests may include:

• CT scan—a type of x-ray that uses a computer to make pictures of the inside of the brain
• MRI scan—a test that uses magnetic waves to make pictures of the inside of the brain
• Ultrasound—a test that uses sound waves to examine the brain

Treatment

Treatment may include:

• Shunt placement (ventriculoperitoneal shunt)—a shunt (a tube placed into the brain) allows excess CSF to drain into another area, usually the abdomen. Sometimes a temporary extraventricular drain (EVD) is placed.
• Third ventriculostomy—a hole is created in an area of the brain. It allows the CSF to flow out of the area where it is building up.
• Removal of the obstruction of CSF flow. For example: removal of tumor or cyst
• Lumbar puncture (spinal tap)—This involves the insertion of a needle between the back bones in the back to remove excess CSF.
• Medicines—In some cases, medicines, such as acetazolamide (Diamox) and furosemide (Lasix), may decrease the production of CSF.
• Other medicines such as steroids or mannitol may decrease swelling around lesions which are causing obstruction of CSF flow.

If you are diagnosed with hydrocephalus, follow your doctor's instructions.

Prevention

There are no known ways to prevent all cases of hydrocephalus. In general:

• Get regular prenatal care.
• Protect yourself or your child from head injuries.
• Keep your child’s vaccines up to date.

Preliminary research suggests that some cases due to brain bleeding in the newborn period may be preventable. Cytomegalovirus or toxoplasmosis acquired by a mother during pregnancy may be a cause of hydrocephalus in a newborn baby. Mothers may reduce their risk of being infected with toxoplasmosis with these steps:

• Carefully cook meat and vegetables.
• Correctly clean contaminated knives and cutting surfaces.
• Avoid handling cat litter, or wear gloves when cleaning the litter box.

Pet rodents (mice, rats, hamsters) often carry a virus called lymphocytic choriomeningitis virus (LCV). LCV infection acquired from pets during pregnancy can lead to hydrocephalus. This is preventable by avoiding rodent contact.

Infection with chickenpox or mumps during or immediately after pregnancy may also lead to hydrocephalus in the baby. Both of these infections can be prevented with vaccination. Other preventable infections may also cause hydrocephalus. People who have risk factors for hydrocephalus should be carefully monitored. Immediate treatment might prevent long-term complications.