Alternative Names
"water on the brain"
Symptoms & Characteristics
Hydrocephalus is a condition in which the primary characteristic is excessive accumulation of fluid in the brain. Hydrocephalus was once known as "water on the brain." The "water" that accumulates is actually cerebrospinal fluid (CSF) -- a clear fluid surrounding the brain and spinal cord. The excessive accumulation of CSF results in an abnormal dilation of the spaces in the brain called ventricles. This dilation causes potentially harmful pressure on the tissues of the brain.
Hydrocephalus may be congenital or acquired.
- Congenital hydrocephalus is present at birth.
- Acquired hydrocephalus develops at some point after birth and can affect individuals of all ages.
Symptoms of hydrocephalus vary with age, disease progression, and individual differences in tolerance to CSF.
- In infancy, the most obvious indication of hydrocephalus is often the rapid increase in head circumstance or an unusually large head size.
- In older children and adults, symptoms may include headache followed by vomiting, nausea, papilledema (swelling of the optic disk, which is part of the optic nerve), downward deviation of the eyes (called "sunsetting"), problems with balance, poor coordination, gait disturbance, urinary incontinence, slowing or loss of development (in children), lethargy, drowsiness, irritability, or other changes in personality or cognition (including memory loss).
Treatment
The goal of treatment is to reduce or prevent brain damage by improving the flow of CSF. The type of treatment used is dependent upon the cause of the hydrocephalus.
How Common Is It?
The overall incidence of hydrocephalus is not known. It most often occurs in children, but it can also affect adults and the elderly.
Genetics & Inheritance
Congenital hydrocephalus can have both genetic and non-genetic causes.
- Environmental factors such as certain prenatal infections (i.e. toxoplasmosis) can cause hydrocephalus.
- Congenital hydrocephalus can also be a feature of a genetic condition. In these genetic conditions, there are often additional characteristic mental and/or physical defects. For example, hydrocephalus can be found in people with certain chromosome abnormalities, achondroplasia or Hurler syndrome. Congenital hydrocephalus also can occur secondary to another birth defect, such as spina bifida, stenosis of aqueduct of Sylvius or atresia of foramen of Magendie.
Acquired hydrocephalus can be caused by many different factors. Some of these factors include meningitis, encephalitis, tumors of the central nervous system, surgical complications or injury/trauma.
Overall, the recurrence risk for hydrocephalus within a family is dependent upon the cause of the condition in the affected person. A genetic consultation with a trained genetic professional is important for a complete evaluation, accurate diagnosis, as well as discussion of the benefits and limitations of testing and recurrence risk.
Genetic Testing
In the absence of a known genetic cause/condition, genetic testing for hydrocephalus is unavailable. During pregnancy, a comprehensive ultrasound (a detailed fetal ultrasound) may be helpful in visualizing hydrocephalus. After birth, head imaging may be used o possibly detect hydrocephalus.
It is always recommended to see genetic counseling with a trained genetic professional for a complete evaluation, accurate diagnosis, and discussion of the benefits and limitations of testing and recurrence risk. Use our find a genetic professional directory to locate a trained genetic professional in your area.
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