Diagnosing Hydrocephalus

What are the signs and symptoms of hydrocephalus?

In infancy (usually before 3 years of age) the head size grows too rapidly and the head becomes too large. The baby's soft spot at the top of the head may be full or tense, and the veins distended. Typically, an infant's pediatrician should be measuring the child's head circumference at each office visit. This information is then plotted on a chart which contains the expected growth curves for the head. If a child's head is growing too fast, it becomes very apparent on the chart and further studies should be caried out. The sutures of the skull may fail to join, the scalp may become thin and shiny and the veins may become clearly visible.
The infant may be irritable, lethargic or unusually fussy; the appetite may be poor and repeated vomiting may occur. The eyes may be deviated downward (a condition referred to as sunsetting eyes) or there may be limited ability to look upward. or the eyes may cross. The infant or young child may have delays in development. There may be subtle changes such as reduced movement of the legs, or persistence of kicking movements.

In the older child in whom the skull bones have fused, the head size usually doesn't grow abnormally. The increased intracranial pressure can cause headaches, irritability, sleepiness, nausea or vomiting, visual problems, neck pain, seizures (rarely), or a change in behavour, personality or school performance. An inability to concentrate or remember things may also develop. Lethargy, drowsiness, balance problems, and double vision are common symptoms. The child may have difficulty looking upwardsun (setting eyes), or have crossed eyes.

I adolescents and adults hydrocephalus will produce a dementia. There can be loss of acquired intellectual functions, this will show up as difficulty at school or at work, loss of judgement, memory problems, or changes in personality and behaviour.
The Babinski, or plantar, reflex can by used to indicate brain or spinal chord disease, in children over a year old. This test is done by drawing a blunt object along the outer edge of the foot from the heel to the little toe. A normal, or flexor response, is if the toes bunch together and move downwards. The Babinski reflex, is the extensor response, where the big toe moves upwards can indicate some problem. Until a child is a year old, the Babinski reflex is always present.
A finger-to-nose reaction is where the neurosurgeon will hold up a finger, and then ask the patient touch the doctors finger and then ones own nose as quickly as possible. This can indicate neurological or visual problems.
One can also test for pronator drift. This is done by having the patient stand, close their eyes, and then extent both arms in front with the palms up. If one arm waves, or drifts down and to the side, this could indicate damage to the motor area of the brain.

How is hydrocephalus diagnosed?

Depending on the child's age at the time of discovery various radiographic techniques are available to confirm the diagnosis.

In the first six to twelve months of life, the diagnosis can often be made with an ultrasound(sonogram) of the brain may show the enlarged ventricles.. After the skull fuses the diagnosis is best made with MRI or CT. Each of these tests have their plusses and minuses, but overall most neurosurgeons would favor an MRI scan. While this test takes longer then a CT scan and thus usually requires sedation, it gives a much better picture of the brain and the possible cause of the hydrocephalus. This information may effect the treatment options for the child.

The CT scan is a quick, easy, and inexpensive way to diagnose hydrocephalus. It is sufficient in many cases of hydrocephalus, particularly when the cause of the hydrocephalus is already known. However, a CT scan involves a small amount of radiation, and it may not adequately detect some of the causes of hydrocephalus.

An MRI scan takes a lot longer to perform (and therefore may require sedation or even general anesthesia for some infants and children), may be difficult for people who are claustrophobic, is more involved and expensive to perform. It often is not necessary to make the diagnosis of hydrocephalus, but may be very helpful in cases where the cause of the hydrocephalus is in doubt or if there are other abnormalities of the brain. In addition, the MRI scan can give information about whether the cerebral aqueduct (the passageway between the third and fourth ventricles) is blocked, and may suggest a newer form of treatment for hydrocephalus, called endoscopy (see below).

CT(Computed Tomography)- This is a special x-ray image of the brain to determine the size of the ventricles, if there is a tumor or obstruction, and the size and location of the tumor. The test is performed by having the patient lie on a flat x-ray table which slides into a round, open scanner. The x-ray images are taken as the patient is lying still on the x-ray table. Often, this test involves the injection of a contrast dye to obtain better images of the brain structures (be sure to tell your health care provider if you are allergic to dye or have ever had a reaction to dye).

MRI (magnetic resonence image)- This is a special non-x-ray image of the brain to determine the size of the ventricles, if there is a tumor or obstruction, and the size and location of the tumor. No x-rays are used in this test. The test is performed by having the patient lie on a flat imaging table, which slides into an enclosed tube. It is important to lie very still while in the scanner, as the pictures are very sensitive to any movement. You will hear a machine-like sound, as the pictures are taken. The space inside the tube is quite snug, therefore, be sure to tell your health care provider if you are claustrophobic, or uncomfortable in very tight places. Because this test is performed with a special high-power magnet, it may not be performed on anyone with a metal implant (ie. artificial limbs, artificial joints, aneurysm clips, shrapnel, or metal heart valves). If you are unsure of any metal in your body, please tell the MRI technician before the test begins.