Hydrocephalus is also known as “water in the brain.”  It is a condition in which there is an abnormal accumulation of cerebrospinal fluid (CSF) in the ventricles, which are cavities in the brain.  In infants with hydrocephalus, CSF builds up in the central nervous system, causing the soft spot near the front of the scalp, known as the anterior fontanelle, to bulge and the head to be larger than expected. There is also a soft spot near the back of the head known as the posterior fontanelle. Early symptoms may include sundowning, which is when the eyes appear to gaze downward; irritability; seizures; separated scalp sutures; sleepiness; and vomiting.

In newborns with hydrocephalus, the head circumference rapidly enlarges and may surpass the 97th percentile when measured at pediatric visits.  If the skull bones have not yet firmly joined together at this age, bulging, firm anterior and posterior fontanelles may be present when the patient is in an upright position. The infant may exhibit fretfulness, poor feeding, and frequent vomiting.

As the hydrocephalus progresses, torpor, a state of sluggishness and reduced metabolism, sets in and the infant shows lack of interest in his/her surroundings. In a later stage, the upper eyelids become retracted and the eyes turn downwards (due to hydrocephalic pressure on the mesencephalic tegmentum and paralysis of upward gaze). Movements become weak and the arms may become tremulous.  There may be reduction of vision. Over time, the head becomes so enlarged that the growing child becomes bedridden and he/she is unable to lift or even move this huge object attached to its neck.

Hydrocephalus is diagnosed through clinical neurological evaluation and by using cranial imaging techniques such as ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), or pressure-monitoring techniques. The most common initial diagnostic test to determine hydrocephalus is an image of the brain (CT Scan or MRI) to identify the enlarged ventricles (spaces) within the brain that are typical of hydrocephalus.

Hydrocephalus is often treated with the surgical placement of a shunt system. This system diverts the flow of CSF from a site within the central nervous system (CNS) to another area of the body where it can be absorbed.  A shunt is a flexible but sturdy tube composed of silicone and plastic.   A shunt system consists of a shunt tube, a catheter, and a valve. One end of the catheter is placed into one of the dilated a ventricles inside the brain.  Depending on the situation, it could also be placed into a cyst or somewhere near the spinal cord. The other end of the catheter is usually placed within the abdominal cavity.  It could also be placed into any area, such as the heart, where the extra cerebrospinal fluid can be drained and absorbed.  The valve located along the catheter maintains one-way flow and regulates the rate of CSF flow.

Hydrocephalus can be effectively treated with a shunt; however, there is still a potential for complications. The shunt can become blocked. Symptoms of blockage include headache and vomiting. There may be other problems with the shunt such as kinking, tube separation, or infection in the area of the shunt. Other complications may include infections such as meningitis or encephalitis, intellectual impairment, and nerve damage.  Untreated hydrocephalus has a 50-60% death rate. Survivors have varying degrees of intellectual, physical, and neurological disabilities.