The Mayo Clinic reports that about 4,000 infants in the United States are born with hydrocephalus, and an estimated 6,000 children develop hydrocephalus during the first 2 years of life. The mechanics of hydrocephalus are interesting. The spinal cord and the brain are cushioned or protected from jarring injury by the systemic flow of cerebrospinal (CSF) fluid. If there is a blockage in some portion of any cerebral pathway, fluid can build up. This blockage can be acquired or can be congenital. The obstruction of the channel and buildup of CSF fluid are the dominant characteristics of hydrocephalus.
The word hydrocephalus originates from two Greek words: hydro means “water” and cephalus means “head.” Hydrocephalus is then a condition in which excess fluid (CSF fluid—not water) accumulates in the brain due to (1) over-secretion of CSF, (2) obstruction of CSF passages, or (3) impaired absorption of CSF. The signs and symptoms of this condition vary depending on the age when the symptoms initiate. Because the skull bones of an infant are not yet fused, continued pressure causes the expansion of the head in all directions; it expands to accumulate the buildup of the CSF fluid, which can result in an increasing head size. There are numerous common signs in infants, in addition to an unusually large head. These symptoms might include vomiting, developmental delay, and depending on the amount of fluid buildup, seizures. In older children, there may be a slowing of development or loss of already achieved development; physical symptoms including nausea, vomiting, and headaches; and problems with motor skills, like balance and coordination.
Hydrocephalus is a serious condition because as CSF accumulates, it displaces and kills neighboring neurons, the building blocks of the central nervous system. The condition is very treatable; however, some children have developmental delays, muscle tone and movement issues, eye movement and speech impairments, and feeding problems. Once the condition is diagnosed, the most imperative goals are to reestablish the flow—absorption and production—of CSF between the brain and spinal cord and reduce the pressure in the child’s head. There are two typical treatment options. The most common course of treatment is the placement of a shunt (a tube) inside the head to regulate the flow of CSF. This tube runs under the skin into the stomach or abdomen. The shunt track can irritate surrounding brain tissue and increase the potential for seizures. The second, less common (although gaining in acceptability) treatment is endoscopic third ventriculostomy (ETV). This procedure allows for creating an alternative pathway around the blockage that allows the CSF to flow unimpeded.
Hydrocephalus can also occur as a secondary effect to some other pathological event or process. This could be either prenatal or postnatal in origin. For instance, some prenatal disorders, such as spina bifida, Dandy-Walker malformation, Arnold-Chiari malformation, and stenosis of the aqueduct of Sylvius, often result in the buildup of excess CFS fluid in the brain. Other causes of hydrocephalus, both prenatal and postnatal, include infections (meningitis, encephalitis), vascular abnormalities, tumors, cysts, and other disease processes.
- Anderson, V., Northam , Hendy, J., & Wrennall, J. (2001).Developmental neuropsychology: A clinical approach. East Sussex, UK: Psychology Press.
- Cleveland Clinic, Neuroscience Center, http://www.cleveland.org
- Kolb, , & Whishaw, I. Q. (2003). Fundamentals of human neuropsychology (5th ed.). New York: Worth Publishers.
- Mayo Clinic, http://www.mayoclinic.org