Causes of Hydrocephalus

Obstruction causes CSF to build up in the brain. If the cause is congenital, symptoms such as an enlarged head may be present at birth. Acquired hydrocephalus can develop at any age as a result of head trauma or illness.

Congenital Hydrocephalus

Congenital hydrocephalus occurs during fetal development and is present at birth. Causes include infections (e.g., cytomegalovirus [CMV], toxoplasmosis, rubella) and hemorrhaging or internal bleeding in the brain.

The following congenital malformations are commonly associated with CSF obstruction:

  • Aqueductal stenosis–narrowing of the pathway to the fourth ventricle
  • Arnold-Chiari malformations–small part of the cerebellum protrudes into the spinal canal
  • Dandy-Walker syndrome–enlarged fourth ventricle due to obstruction in pathway
  • Spina bifida–portion of the spinal cord is pushed through an abnormal opening between two vertebrae

Acquired Hydrocephalus

Acquired hydrocephalus can occur at any age. The following conditions may cause CSF obstruction and subsequently acquired hydrocephalus:

  • Bleeding (hemorrhage)
  • Brain trauma (i.e., result of injury)
  • Brain tumor
  • Cyst (i.e., a fluid-filled sac)
  • Infection (e.g., cerebral abscess, bacterial meningitis)

Hemorrhaging, traumatic brain injury, and infection are seen in some premature births; premature births may be a risk factor for hydrocephalus.

Hydrocephalus Signs and Symptoms

Symptoms of hydrocephalus are determined by the following factors:

  • Age
  • Degree of ventricular enlargement
  • Rate of hydrocephalus development
  • Type
  • Underlying condition

Symptoms of Hydrocephalus in Infants

The characteristic symptom seen in infants is enlargement of the head. An infant's skull expands to accommodate excess CSF because the bones of the skull have not closed yet.

Very young children commonly experience irritability, poor feeding, and lethargy.

Symptoms of Hydrocephalus in Children and Adults

Children and adults may experience the following symptoms:

  • Blurred or double vision
  • Cognitive difficulties
  • Downward gaze or "sun-setting eyes"
  • Headache
  • Imbalance and dizziness
  • Incontinence
  • Irregular gait
  • Lethargy
  • Nausea
  • Poor coordination
  • Visual disturbances
  • Vomiting
  • Weakness

Seizures are uncommon, but do occur in some cases.

Normal pressure hydrocephalus (NPH), which is more common in patients over the age of 60, often causes memory loss, trouble speaking, emotional changes, incontinence, irregular gait, and dementia.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 01 Sep 2001

Last Modified: 15 Nov 2011