Diagnosis

A diagnosis of hydrocephalus is usually based on:

• Your answers to the doctor's questions about signs and symptoms
• A general physical exam
• A neurological exam
• Brain-imaging tests

Neurological exam

The type of neurological exam will depend on a person's age. The neurologist might ask questions and conduct relatively simple tests in the office to judge muscle condition, movement, well-being and how well the senses are functioning.

Brain imaging

Imaging tests that can help diagnose hydrocephalus and identify underlying causes of the symptoms include:

• Ultrasound. This test is often used for an initial assessment for infants because it's a relatively simple, low-risk procedure. The ultrasound device is placed over the soft spot (fontanel) on the top of a baby's head. Ultrasound might also detect hydrocephalus before birth during routine prenatal examinations.

• MRI. This test uses radio waves and a magnetic field to produce detailed images of the brain. This test is painless, but it is noisy and requires lying still.

  MRI scans can show enlarged ventricles caused by excess cerebrospinal fluid. They can also be used to identify causes of hydrocephalus or other conditions contributing to the symptoms.

  Children might need mild sedation for some MRI scans. However, some hospitals use a fast version of MRI that generally doesn't require sedation.

• CT scan. This specialized X-ray technology produces cross-sectional views of the brain. Scanning is painless and quick. But this test also requires lying still, so a child usually receives a mild sedative.

  CT scanning produces less detailed images than MRI does and causes exposure to a small amount of radiation. CT scans for hydrocephalus are usually used only for emergency exams.