Hydrocephalus literally means “fluid on the brain.” The brain sits within the skull and is surrounded by cerebrospinal fluid (CSF). CSF is produced by the “choroid plexus” within the brain. After it has circulated through the ventricles (fluid-filled cavities within the brain) it is reabsorbed into venous blood in the head where the CSF can be recycled.
In hydrocephalus there is too much cerebrospinal fluid on the brain. This can occur from a blockage of CSF drainage, known as obstructive hydrocephalus; or it can occur from a decreased CSF reabsorption or an overproduction of CSF, known as communicating hydrocephalus. Acquired hydrocephalus is reported to occur in 1-1.5% of the population. It can be congenital in 0.9-1.8/1000 births.
Acquired hydrocephalus can be a result of an infection involving the brain or brain coverings. It can also occur after a brain bleed such as a subarachnoid hemorrhage or an intraventricular hemorrhage. It can also result from a brain mass, or it can be a postoperative complication.
The extra fluid on the brain causes pressure on the brain which leads to the symptoms. Symptoms can include headache, nausea and vomiting, difficulty walking, confusion, irritability, downward gaze, and lethargy.
Diagnosis and treatment
Diagnosis is made by CT or MRI evaluating the ventricle size. Treatment is usually surgical. A spinal tap may be done prior to surgery for diagnosis and/or temporary treatment. Commonly, a ventriculoperitoneal shunt (VP shunt) is performed. In this procedure, a tube is placed in your body that drains CSF from inside the ventricle in your brain to the peritoneal cavity in your abdomen. This tube is tunneled under your skin from behind your ear to your belly.
There are several other surgical options to treat hydrocephalus, but a VP shunt is most commonly used. Increasingly, endoscopic third ventriculostomy is being performed for patients with obstructive hydrocephalus.
Lindsey Parker PA-C and Justin F. Fraser MD