What Is Hydrocephalus?
Hydrocephalus is the buildup of the cerebrospinal fluid (CSF) inside the skull that leads to brain swelling. Hydrocephalus can be caused by a decreased absorption of CSF or an overproduction of CSF.
Cerebrospinal fluid (CSF) is the liquid that surrounds the brain and spinal cord which brings nutrients to and from the brain, removes wastes and acts as a shock-absorbing cushion for the brain.
What Causes Hydrocephalus?
The causes of hydrocephalus vary; hydrocephalus may be:
Congenital - present at birth, caused by genetic abnormalities or influences occurring during fetal development. Congenital hydrocephalus includes: neural tube defects, arachnoid cysts, Dandy-Walker Syndrome, Chiari Malformation, acqueductal stenosis.
Idiopathic - cause for hydrocephalus is unknown. Examples include normal pressure hydrocephalus.
What Are the Types of Hydrocephalus?
Hydrocephalus can be described as:
1) Noncommunicating Hydrocephalus: also called "obstructive hydrocephalus", occurs when obstruction in the ventricular system (set of cerebrospinal fluid containing structures) prevents the CSF from reaching the arachnoid villi in the brain (microscopic projections of fibrous tissue on the arachnoid membrane that covers the brain). Noncommunicating Hydrocephalus can be caused by tumors, congenital malformations, inflammation, hemorrhage, or congenital aqueductal stenosis.
2) Communicating Hydrocephalus: results from impaired reabsorption of CSF from the arachnoid villi into the venous system. Communicating Hydrocephalus can be caused by post-infective meningitis scarring, too few villi formed, villi that are obstructed by infectious debris or blood clots, or adenomas of the choroid plexus that cause overproduction of CSF.
3) Hydrocephalus Ex-Vacuo: occurs when a traumatic brain injury or stroke causes damage to the brain; actually shrinking the brain.
4) Normal Pressure Hydrocephalus: most common among elderly, and may arise from head trauma, sub-arachnoid hemorrhage, infection, tumor, or surgical complication.
What Are the Symptoms of Hydrocephalus?
Symptoms of hydrocephalus vary with age, among other factors. An infant's skull can expand to accommodate the buildup of CSF as the sutures haven't yet closed as they have in adults. Symptoms of hydrocephaly in infants can include vomiting, sleepiness, irritability, seizures, and downward deviation of the eyes. Other possible signs are unusually large head size or a rapid increase in head circumference, or bulging fontanelles.
One symptom of hydrocephalus in older children and adults includes headaches. These headaches are often followed by nausea and vomiting. Other possible signs are balance problems, poor coordination, difficulty walking, lethargy or drowsiness, and urinary incontinence. Personality changes can accompany hydrocephalus, such as irritability, as well as memory loss or other changes in cognition and slowing or loss of developmental progress. There may also be symptoms related to sight, such as blurred or double vision, downward deviation of the eyes, and swelling of the optic disk (a part of the optic nerve).
Symptoms of Normal Pressure Hydrocephalus include problems walking, complaints of "feet feeling stuck", general slowing of movements, and impaired bladder control that leads to urinary frequency and/or incontinence. There may also be dementia or other progressive mental impairment.
How is Hydrocephalus Diagnosed?
There are several methods used to diagnose hydrocephalus. Clinical neurological evaluations are one method. The physician may also perform a lumbar puncture (spinal tap) and/or monitor inter-cranial pressure. There are various imaging tests that can help diagnose hydrocephalus, such as ultrasound, CT Scan, and MRI.
How is Hydrocephalus Treated?
Hydrocephalus is generally treated via a surgically implanted shunt system. The shunt diverts the flow of CSF from the central nervous system to another area of the body where it can be reabsorbed.
CSF shunt systems are imperfect devices and their failures can include mechanical failure, infections, obstructions, as well as the need to lengthen and/or replace the catheter. Shunt systems generally require prodigious monitoring and regular medical follow-up care as shunt complications usually require revisions before they lead to more severe problems.
What is the Prognosis for Someone Diagnosed with Hydrocephalus?
The prognosis for those diagnosed with hydrocephalus is as variable as the cause for the condition. Certain types of hydrocephalus have better prognoses than others.
Prognosis of hydrocephalus is complicated by any associated conditions, timeliness of the diagnosis and the success of the treatment. It's unknown how reversible the damage to the brain is after shunt placement. Early intervention and shunt placement can lead to more positive outcomes.
Hydrocephalus is generally a diagnosis that requires rehabilitation and educational interventions as well as treatment by an interdisciplinary team.
Left untreated, hydrocephalus may be progressive and fatal.
Additional Hydrocephalus Resources:
Hydrocephalus Association - The Hydrocephalus Association provides support, education and advocacy for people whose lives have been touched by hydrocephalus and the professionals who work with them.
Hope for People With Normal Pressure Hydrocephalus - a site devoted to distinguishing normal pressure hydrocephalus from Alzheimer's disease or Parkinson's Disease. Full of information about Normal Pressure Hydrocephalus.
Children's Hydrocephalus Support Group - site for parents of children with hydrocephalus sponsored by Seattle Children's Hospital.
National Hydrocephalus Foundation -non-profit devoted to assembling and disseminating information about hydrocephalus and its outcomes as well as establishing a communication network for those affected by hydrocephalus.