Diagnosing Hydrocephalus in Children

Physicians at Hassenfeld Children’s Hospital at NYU Langone have expertise in diagnosing pediatric hydrocephalus, an accumulation of cerebrospinal fluid within the cavities of the brain, called ventricles. This fluid, also called cerebrospinal fluid, surrounds and cushions the brain and spinal cord, and helps distribute important nutrients within the central nervous system.

When spinal fluid builds up in the ventricles, it causes them to enlarge. This can lead to serious complications from increased pressure on the brain, such as brain damage and mental, developmental, and physical disabilities.

Causes and Types of Pediatric Hydrocephalus

The human body produces about one pint of cerebrospinal fluid every day, and continuously replaces the fluid as it is absorbed in the body. Hydrocephalus occurs when spinal fluid is not properly absorbed or when a blockage forms along the pathway that circulates spinal fluid, preventing the fluid from flowing normally throughout the brain and spinal column.

Hydrocephalus is one of the most common pediatric neurological problems and occurs in about 1 in 1,000 children. It can be present at birth, which is called congenital hydrocephalus, or it can develop after birth—called acquired hydrocephalus—as a result of neurological conditions such as head trauma, brain tumors, cysts, bleeding in the brain, malformation of the central nervous system, or infection. Sometimes children develop hydrocephalus without a known cause.

Hydrocephalus may also be “communicating” or “noncommunicating.” Communicating hydrocephalus occurs when the flow of spinal fluid is blocked after it exits the ventricles. This form of hydrocephalus is called “communicating” because the spinal fluid can still flow between the ventricles, which remain open. Noncommunicating, or obstructive, hydrocephalus happens when the flow of spinal fluid is blocked along one or more of the narrow passages connecting the ventricles.

Symptoms of Pediatric Hydrocephalus

Pediatric hydrocephalus can affect children of all ages, but the signs and symptoms vary by age of onset. The most obvious sign of hydrocephalus in infants is a rapid increase in head circumference or an unusually large head size. Other symptoms may include seizures, vomiting, sleepiness, irritability, or eyes that constantly gaze downward.

Because the skulls of older children cannot expand to accommodate the buildup of cerebrospinal fluid, they may experience different symptoms, such as severe headaches along with nausea and vomiting, vision problems, lethargy, and slowed or halted developmental progress in speech, reasoning, or other age-appropriate milestones.

To diagnose hydrocephalus, a neurosurgeon or neurologist takes a thorough medical history and performs a neurological evaluation and physical exam. Doctors then perform an ultrasound, MRI scan, or CT scan to confirm enlargement of the ventricles and determine the cause of the hydrocephalus.

Neurological Evaluation

Doctors may perform a neurological examination and may recommend neuropsychological testing to assess if your child has any cognitive impairment. The neuropsychological testing involves asking questions about your child’s attention, memory, reasoning, and language abilities.


For infants, doctors may use ultrasound imaging to look at the fluid in the ventricles. Ultrasound uses sound waves to produce images of structures in the body. It is often used for infants because a baby’s soft spot on the top of the head—called the fontanel—allows the sound waves to penetrate the skull safely.

Doctors and radiologists may also use ultrasound to detect hydrocephalus before a baby is born, during routine prenatal examinations.

MRI Scan

A doctor may order an MRI scan to view the brain, provide information about the surrounding brain tissues, look for enlarged ventricles, and evaluate the flow of cerebrospinal fluid.

An MRI can also show the presence of tumors, congenital malformations, and other conditions that may be responsible for hydrocephalus. This type of imaging uses a magnetic field and radio waves to create computerized two- or three-dimensional images of the inside of the head.

Some MRI scans can take up to an hour and may require mild sedation, since the child must lie still during the scan.

CT Scan

A CT scan uses X-ray and computer imaging to create detailed pictures of the brain. Doctors use CT scans to discover if the ventricles are enlarged, indicating cerebrospinal fluid buildup. This diagnostic test is very quick and usually avoids the need for sedation in a young child.

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