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Hydrocephalus (‘Hydro’ meaning water, and ‘cephaly’ meaning head in Greek) is a condition where there is increased cerebrospinal fluid (CSF) volume inside the head. This can be a result of obstruction to the normal CSF circulation, or rarely, a result of over-production of CSF, for example, due to an underlying CSF-secreting tumour. Hydrocephalus can classified as communicating or non-communicating depending if there is communication with subarachnoid space where CSF is absorbed.

Hydrocephalus leads to increased pressure inside the skull (‘raised intracranial pressure’), which can cause drowsiness, loss of consciousness and even death.

Hydrocephalus can affect all age groups, and is found in about 1% of the population. Infants with hydrocephalus are often diagnosed at birth with spina bifida (myelomeningocoele) and Chiari-II Malformation. Children may have hydrocephalus from obstructions due to tumours or narrowings in the natural fluid channels (e.g. aqueductal stenosis). Adults may develop hydrocephalus also from tumours (e.g. colloid cysts), infection (e.g. meningitis) or after bleeding in the brain (e.g. subarachnoid haemorrhage or intraventricular haemorrhage).


There are numerous causes for hydrocephalus, which may be divided into congenital or acquired…


  • Chiari Malformation (Types 2 and less commonly Type 1).
  • Aqueductal stenosis.
  • Dandy Walker malformation.


  • After infection – Meningitis.
  • After haemorrhage – Subarachnoid haemorrhage from aneurysm, or bleeding into ventricles (intraventricular haemorrhage).
  • Tumours – Located within the ventricles, such as medulloblastoma, ependymoma, colloid cysts, pituitary tumours).
  • Normal Pressure Hydrocephalus.


In adults, the most common symptom is headache associated with increased intracranial pressure. Headaches typically would be worse with lying, coughing, straining and strenuous activities. There may also be blurred vision, double vision, difficulty walking and urinary incontinence.

In children, there may be disproportionate growth in head size (‘increasing head circumference’) when compared to the rest of the body. There may also be difficulty with looking upwards and irregular breathing or breathing difficulties. In severe or extreme cases, there may be drowsiness and loss of consciousness or death at its extreme.

Tests / Diagnosis

  • Neurological examination – abnormal findings found by medical staff on physical examination.
  • Neuroimaging – MRI (magnetic resonance imaging) and / or CT (computed tomography) scan of the brain and spine. Sometimes, additional procedures are performed to measure the pressure inside the head (‘Intracranial Pressure’) with a pressure monitor.


Treatment for hydrocephalus is mainly with surgery. There are two main operations performed: Endoscopic Third Ventriculostomy or Ventriculoperitoneal Shunts.

Medications for hydrocephalus may be beneficial in some cases, and are used in rare situations, such as prior to emergency surgery or extreme hydrocephalus.

Related Information

Endoscopic Third Ventriculostomy Ventriculoperitoneal Shunt