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By Dr N M Rithvic
Consultant Neurosurgeon
Published on 17/10/2022

Definition

Hydrocephalus is a condition in which excess cerebrospinal fluid (CSF) accumulates within the brain's fluid-containing cavities or ventricles. The word "hydrocephalus" comes from the Greek words "hydro" (water) and "cephalus" (head). Although the term translates as "water on the brain," it actually refers to the accumulation of CSF, a clear organic liquid that surrounds the brain and spinal cord. CSF is constantly circulated within the ventricles of the brain and serves a variety of important functions:

  • It acts like a shock absorber for the brain and spinal cord.
  • It serves as a vehicle to deliver nutrients and removes waste from the brain.
  • It circulates between the cranium and the spine to regulate pressure changes.

When CSF accumulates around the brain, it can exert harmful pressures on the brain tissues confined within the skull. CSF accumulation occurs as a result of either an increase in fluid production, a decrease in fluid absorption, or a condition that prevents normal fluid flow through the ventricular system.

When CSF accumulates around the brain, it can place harmful pressures on the brain tissues confined within the skull. CSF accumulation occurs as a result of an increase in fluid production, a decrease in fluid absorption, or a condition that prevents normal fluid flow through the ventricular system.

Hydrocephalus can happen at any age, but it is most common in infants and adults over the age of 60. Hydrocephalus affects 1 or 2 out of every 1,000 children. The majority of these cases are frequently diagnosed before birth, during delivery, or in early childhood.


Symptoms:

The symptoms of hydrocephalus vary greatly between individuals and across age groups. Infants and young children are susceptible to symptoms such as vomiting from increased intracranial pressure, while adults may experience loss of function such as walking or thinking.

Infants

  • Unusually large head size
  • Rapidly increasing head circumference
  • Prominent scalp veins
  • Downward deviation of eyes or sunset sign
  • Vomiting
  • Sleepiness
  • Seizures
  • Irritability

Children and Adolescents

Adults

  • Headache
  • Nausea and vomiting
  • Difficulty walking or gait disturbances
  • Loss of balance or coordination
  • Lethargy
  • Bladder incontinence
  • Impaired vision
  • Impaired analytical skills
  • Mild dementia

Causes:

The causes of hydrocephalus are poorly understood. Hydrocephalus can be inherited, be associated with developmental disorders such as spina bifida or encephalocele, or caused by brain tumors, head injuries, hemorrhage, or diseases such as meningitis. Hydrocephalus can be classified based on its onset, the presence of structural defects, or CSF pressures.

  • Acquired Hydrocephalus: This type of hydrocephalus that appears at birth or later in life and is usually caused by a disease or injury.
  • Congenital Hydrocephalus: This type is caused by events during fetal development or due to genetic abnormalities and present at birth.
  • Communicating Hydrocephalus: When there is no blockage to CSF flow within the ventricular system, this type of hydrocephalus occurs. The condition is caused by either insufficient absorption or an abnormal increase in the amount of CSF produced.
  • Non-communication (Obstructive) Hydrocephalus: When the flow of CSF is blocked along one or more of the passages connecting the ventricles, the pathways enlarge, causing an increase in pressure within the skull.
  • Normal Pressure Hydrocephalus: It's a type of communicating hydrocephalus that can happen at any age, but it's most common in the elderly. It is characterized by dilated ventricles and normal pressure in the spinal column.
  • Hydrocephalus Ex-vacuo: It affects adults and occurs when a degenerative disease, such as Alzheimer's disease, stroke, or trauma, causes brain damage.

Testing and Diagnosis:

Once a physician suspects hydrocephalus, they perform clinical evaluation, including a detailed patient history and performing a physical exam to assess the condition. A complete neurological examination, including the following tests, is recommended to confirm the diagnosis:

  • CT scan
  • MRI
  • Lumbar puncture
  • Intracranial pressure monitoring
  • Isotope cisternography

Treatment:

There are several ways to treat hydrocephalus. It may be treated directly by removing the cause of CSF obstruction or indirectly by diverting the excess fluid, depending on the underlying etiology. The most common method of treating hydrocephalus is to implant a device known as a "shunt" to divert excess CSF away from the brain.

The shunt is a tube placed in ventricular space along with a catheter and a valve to drain excess cerebrospinal fluid from the ventricle inside the brain to another body cavity where it can be absorbed naturally by the body.

Once implanted, the shunt system is usually left in place for the rest of the patient's life. The shunt system continuously performs its function by diverting CSF away from the brain, thereby maintaining normal intracranial pressure. In some cases, two procedures are performed, one to divert the CSF and another to remove the source of the obstruction (e.g. a brain tumor).

An alternative procedure known as endoscopic third ventriculostomy(ETV) can be used to treat a limited number of patients. A surgeon uses a tiny camera (endoscope) with fiber optics to visualize the ventricles and create a new pathway for CSF flow during this procedure.

Follow-up:

Neurological function will be assessed following surgery. If any neurological issues persist, rehabilitation may be required to improve further. The extent of the damage caused by the hydrocephalus, as well as the ability of the brain to heal may limit recovery.

Because hydrocephalus is a chronic condition, it requires long-term medical monitoring. Follow-up diagnostic tests, such as CT scans, MRIs, and x-rays, can help to determine whether the shunt is functioning properly. If any of the following post-operative symptoms are experienced, you should consult the doctor:

  • Nausea, vomiting, headache, or double vision
  • Fever
  • Abdominal pain
  • Irritability or drowsiness
  • Pain, tenderness, redness, tenderness, pain or swelling of the skin along the length of the tube or incision
  • Return of preoperative neurological symptoms

Prognosis

The prognosis for people suffering from hydrocephalus can vary. Some people recover without complications or recurring problems. Others live with hydrocephalus their entire lives. The causes of hydrocephalus influence the prognosis. Early identification and treatment can improve the chances of a successful outcome.