Hydrocephalus

About

What is hydrocephalus?

Hydrocephalus is a buildup of excess fluid in the cavities (ventricles) deep within the brain. The pressure this causes puts pressure on the brain and can potentially damage brain tissue. Cerebrospinal fluid (CSF) normally flows through the ventricles, bathing the brain and spinal column. The body produces CSF each day and a corresponding amount is absorbed into the bloodstream. It constantly circulates and serves very important functions, including:

  • Absorbs shocks to the brain and spinal cord to prevent injury
  • Keeps the relatively heavy brain buoyant so it can float within the skull
  • Delivers nutrients to the brain 
  • Removes waste from the brain’s metabolism
  • Maintains and regulates constant pressure within the brain, and compensates for blood pressure changes in the brain

If an imbalance develops between the amount of CSF that’s produced and the amount that’s absorbed, it can cause a dangerous accumulation that will get worse if not treated. Hydrocephalus can be fatal. 

Hydrocephalus can develop at any age, but is more common in infants and adults over age 60. In infants and children, hydrocephalus causes head enlargement. Adults and older children may have headaches, vision problems, cognitive difficulties, loss of coordination, and problems with bladder control. Surgery can restore normal CSF levels, although multiple surgeries may be needed. Most patients can lead normal productive lives.

Causes

What causes hydrocephalus?

There are several causes of hydrocephalus, including:

  • It can develop before birth
  • Develops in childhood or adulthood
  • Inherited genetically
  • Occurs with developmental disorders, including spina bifida and encephalocele
  • Brain tumors
  • Head injuries
  • Bleeding in the brain (hemorrhage)
  • Meningitis

The causes of hydrocephalus can be classified by types, including:

  • Acquired hydrocephalus is present at birth, or develops in adulthood due to an injury or disease.
  • Congenital hydrocephalus is present at birth; can happen during fetal development by an inherited genetic defect that blocks the flow of CSF; developmental disorders caused by birth defects in the brain, spine, or spinal cord; complications of premature birth such as bleeding within the ventricles; or infection during pregnancy such as rubella or syphilis that can cause inflammation in the fetal brain tissue. 
  • Communicating hydrocephalus occurs when the flow of CSF is blocked after it leaves the brain’s ventricles, but the CSF can still flow between ventricles. Buildup can also occur due to reduced flow or inadequate absorption of CSF into specialized blood vessels called arachnoid villi, or it can be caused by an abnormal increase in the amount of CSF produced.
  • Normal-pressure hydrocephalus (NPH) is a type of communicating hydrocephalus that is most common in older people. It can be caused by bleeding in the brain’s CSF, head trauma, infection, tumor, or a complication of surgery. However, many cases of NPH have none of these factors present. With NPH the CSF increases slowly enough to allow tissues around the ventricles to compensate. This keeps the pressure inside the head from increasing, and spinal column pressure is normal. NPH causes problems with walking, bladder control, thinking and reasoning. It can be mistaken for Alzheimer’s disease. NPH accounts for more than 5% of all dementias. 
  • Non-communication (obstructive) hydrocephalus occurs if the flow of CSF is blocked along one or more of the narrow passages that connect the ventricles. This causes enlargement of the pathways upstream of the blockage and leads to an increase in skull pressure.
  • Hydrocephalus ex-vacuo is a result of brain damage caused by stroke or injury, chiefly in adults. It can be caused when a degenerative disease (such as Alzheimer’s disease, stroke or trauma) causes the tissue around the ventricles to shrink, making the ventricles bigger than normal.

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Symptoms

What are the symptoms of hydrocephalus?

Symptoms vary among patients and according to age. Symptoms in infants include:

  • Unusually large head that rapidly increases
  • Bulging and tense fontanelle (soft spot before the skull completely hardens)
  • Prominent scalp veins
  • Downward focus of eyes or inability to look outward
  • Vomiting
  • Sleepiness
  • Irritability
  • Seizures

Get immediate medical attention for infants or toddlers with a high-pitched cry, problems with sucking or feeding, recurrent vomiting, or seizures.

Children and teen-ager symptoms include:

  • Headaches
  • Nausea and vomiting
  • Swelling of the optic disc
  • Blurred or double vision including abnormal eye movements
  • Problems with balance, walking and coordination
  • Slowing or loss of developmental progress; decline in school performance
  • Sleepiness or sluggishness
  • Changes in personality
  • Inability to concentrate
  • Seizures
  • Poor appetite
  • Bladder control problems or frequent urination
  • Loss of muscle tone and strength

Symptoms in adults can include many of the children/teen-agers symptoms plus these additional symptoms:

  • Loss of balance or coordination
  • Lethargy
  • Impaired thinking skills
  • Memory loss
  • Mild or worsening dementia

Diagnosis

How is hydrocephalus diagnosed?

Your doctor will do a complete physical exam, and take a detailed patient history. A neurological exam can determine muscle strength, reflexes, coordination, balance, vision and hearing abilities, and mental functioning. Other tests may be used to confirm a diagnosis and help plan treatment options, including:

  • Ultrasound is often used for an infant’s initial assessment 
  • Computed tomography scan (CT) is used for emergency exams
  • Magnetic resonance imaging (MRI) scans can show enlarged ventricles caused by excess CSF, and identify causes of hydrocephalus
  • Spinal tap can estimate CSF pressure and analyze the fluid
  • Intracranial pressure monitoring
  • Isotope cisternography diagnoses problems with the flow of spinal fluid
  • Fundoscopic exam views the optic nerve to check for swelling that may be caused by increased pressure in the brain

Treatment

What are the treatment options for hydrocephalus?

Surgical treatments can include:

  • A shunt (tube) is surgically inserted into the brain and connected to a flexible tube that drains excess fluid into either the chest cavity or the abdomen so it can be absorbed by the body. Shunt systems usually work well but can fail to properly drain CSF if an infection develops or there’s mechanical failure. Shunt failure will cause hydrocephalus symptoms to recur. In children, shunts malfunction in about 40% of the cases during the first year; about 10% per year after that. Multiple surgeries may be needed to repair or replace the shunt during the patient’s lifetime. Shunts require monitoring and regular medical checkups. 
  • Endoscopic third ventriculostomy (ETV) can help a limited number of patients by surgically improving the flow of CSF out of the brain via a tiny hole at the bottom of a ventricle. Complications include bleeding and infections.
  • Choroid plexus cauterization can decrease CSF production using electric current to burn the CSF-producing tissue. This is often used with ETV. 

The nervous system will be evaluated after surgery. If neurological problems still exist, many hydrocephalus patients can benefit from rehabilitation therapies. Recovery can be limited by the extent of damage already caused, and by the brain’s ability to heal. The longer the symptoms are present, the less chance that treatment will be successful. Many people are able to live with hydrocephalus with few limitations.

References

National Institute of Neurological Disorders and Stroke. (April 2020). Hydrocephalus Fact Sheet. Retrieved 12-8-21, {https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Hydrocephalus-Fact-Sheet}
Mayo Clinic. (Sept. 2021). Hydrocephalus. Retrieved 12-8-21, {https://www.mayoclinic.org/diseases-conditions/hydrocephalus/symptoms-causes/syc-20373604}
Mayo Clinic. (Sept. 2021). Hydrocephalus Diagnosis and Treatment. Retrieved 12-8-21, {https://www.mayoclinic.org/diseases-conditions/hydrocephalus/diagnosis-treatment/drc-20373609}
American Association of Neurological Surgeons. (N.d.). Hydrocephalus. Retrieved 12-8-21, {https://www.aans.org/Patients/Neurosurgical-Conditions-and-Treatments/Hydrocephalus}

Information

Medically reviewed by:

Dr. Desiree Levyim

Dr. Desiree Levyim is a board eligible neurologist in practice since 2020. She joins TeleMed2U in our mission to provide increased access to healthcare.

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Initial Visit

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