What is Hydrocephalus?

Hydrocephalus is a neurological condition that occurs when cerebrospinal fluid (CSF) accumulates abnormally within the brain's ventricles, causing increased pressure. CSF normally flows through the brain and spinal cord to cushion, nourish, and remove waste. When its flow is blocked or absorption is impaired, ventricles swell and compress brain tissues.

Hydrocephalus can affect people of all ages, though it's most commonly seen in infants and older adults. In newborns, it affects roughly 1 in every 1,000 live births in the U.S. Among adults over 80, a form called normal pressure hydrocephalus (NPH) becomes more common.

Types

Hydrocephalus is categorized based on how and where the CSF flow is disrupted.

Communicating Hydrocephalus

CSF flows between the ventricles normally but is blocked after exiting them. Subtypes include:

  • Normal Pressure Hydrocephalus (NPH): Affects older adults with symptoms that develop gradually.

  • Hydrocephalus Ex-vacuo: Occurs after brain atrophy, typically from stroke or injury, where CSF fills the extra space.

Obstructive (Non-Communicating) Hydrocephalus

This type results from a physical blockage within the ventricular system, often due to congenital abnormalities or tumors.

Primary vs. Secondary

  • Primary (Congenital): Present at birth due to genetic or developmental issues.

  • Secondary (Acquired): Caused by trauma, infections, hemorrhage, or tumors.

Acute vs. Chronic

  • Acute: Sudden onset requiring emergency care.

  • Chronic: Develops slowly and may go unnoticed for months.

Symptoms

Symptoms vary depending on the patient’s age and the progression of the condition.

In Infants

  • Enlarged head

  • Bulging fontanel

  • Vomiting

  • Poor feeding

  • Sunsetting eyes

  • Irritability

  • Seizures

In Children and Adults

  • Headache

  • Blurred vision

  • Balance problems

  • Cognitive decline

  • Personality changes

  • Urinary incontinence

Normal Pressure Hydrocephalus (NPH)

  • Gait disturbances

  • Memory loss or cognitive decline

  • Urinary urgency or incontinence

Acute Hydrocephalus

  • Rapid mental deterioration

  • Loss of consciousness

  • Coma or brain herniation

Causes

CSF flows through ventricles and into the subarachnoid space before being absorbed into the bloodstream. Obstruction or impaired absorption leads to hydrocephalus.

Congenital Causes

  • Dandy-Walker Syndrome

  • Spina Bifida

  • Chiari Malformations

  • X-linked Hydrocephalus

  • Tuberous Sclerosis

Acquired Causes

  • Intraventricular hemorrhage (often in preterm infants)

  • Meningitis

  • Head trauma

  • Brain tumors

Idiopathic Causes

NPH may arise spontaneously, potentially linked to poor CSF circulation or reabsorption.

Diagnosis

A combination of clinical assessment and diagnostic testing is used.

Medical History & Exam

  • Symptom review

  • Neurological examination

  • Fundoscopic eye exam to check for increased intracranial pressure

Imaging

  • Ultrasound (infants)

  • CT Scan

  • MRI (preferred for detailed evaluation)

Lumbar Puncture

Used to measure CSF pressure or remove fluid. Particularly useful in NPH diagnosis.

Additional Testing

  • Blood tests

  • Genetic testing (for infants)

  • Gait assessment and neuropsychological evaluation

Treatment

The goal is to relieve pressure and prevent brain damage.

Medical Management

  • Acetazolamide (Diamox)

  • Mannitol (Osmitrol)

  • Hyperventilation (temporary measure)

Surgical Treatment

  • Ventriculoperitoneal Shunt (VP Shunt): Most common surgical solution

  • Endoscopic Third Ventriculostomy (ETV): Creates a new drainage pathway

  • Tumor removal (if applicable)

Co-Occurring Conditions

Hydrocephalus often presents with or leads to other health issues:

  • Epilepsy

  • Spina Bifida

  • Cognitive and motor impairments

Living With Hydrocephalus

Outcomes vary widely. Early treatment improves prognosis significantly. Some individuals with mild hydrocephalus live normal lives, while others may have lasting impairments.

Shunts are effective in 60%-80% of NPH cases. Still, shunt failure or infection can occur and requires urgent care.

Warning signs of complications:

  • Headaches

  • Return of initial symptoms

  • Fever

  • Redness along the shunt path