What is hydrocephalus?
Hydrocephalus is a condition characterized by excessive accumulation of fluid in the brain.
- Hydrocephalus may be congenital or acquired.
- Communicating hydrocephalus occurs when cerebrospinal fluid (CSF) can still flow among the ventricles.
- Noncommunicating hydrocephalus, also called "obstructive" hydrocephalus, occurs when the flow of CSF is blocked.
- Hydrocephalus affects about 1 out of every 500 children.
- The most obvious indication of hydrocephalus in children and infants is often a rapid increase in head circumference or an unusually large head size. Other symptoms may include vomiting, sleepiness, irritability, downward deviation of the eyes (also called "sunsetting"), and seizures.
- Older children and adults may experience different symptoms because their skulls cannot expand to accommodate the buildup of CSF.
- Symptoms in older patients may include headache followed by vomiting, nausea, papilledema (swelling of the optic disk which is part of the optic nerve), blurred or double vision, urinary incontinence, lethargy, drowsiness, irritability, or other changes in personality or cognition.
- The causes of hydrocephalus are poorly understood.
- Hydrocephalus is most often treated by surgically inserting a shunt system.
What is hydrocephalus?
The term hydrocephalus is derived from the Greek words "hydro" meaning water and "cephalus" meaning head. As the name implies, it is a condition in which the primary characteristic is excessive accumulation of fluid in the brain. Although hydrocephalus was once known as "water on the brain," the "water" is actually cerebrospinal fluid (CSF)--a clear fluid that surrounds the brain and spinal cord. The excessive accumulation of CSF results in an abnormal widening of spaces in the brain called ventricles. This widening creates potentially harmful pressure on the tissues of the brain.
The ventricular system is made up of four ventricles connected by narrow passages.. Normally, CSF flows through the ventricles, exits into cisterns (closed spaces that serve as reservoirs) at the base of the brain, bathes the surfaces of the brain and spinal cord, and then reabsorbs into the bloodstream.
CSF has three important life-sustaining functions: 1) to keep the brain tissue buoyant, acting as a cushion or "shock absorber"; 2) to act as the vehicle for delivering nutrients to the brain and removing waste; and 3) to flow between the cranium and spine and compensate for changes in intracranial blood volume (the amount of blood within the brain).
The balance between production and absorption of CSF is critically important. Because CSF is made continuously, medical conditions that block its normal flow or absorption will result in an over-accumulation of CSF. The resulting pressure of the fluid against brain tissue is what causes hydrocephalus.
What are the different types of hydrocephalus?
Hydrocephalus may be congenital or acquired. Congenital hydrocephalus is present at birth and may be caused by either events or influences that occur during fetal development, or genetic abnormalities. Acquired hydrocephalus develops at the time of birth or at some point afterward. This type of hydrocephalus can affect individuals of all ages and may be caused by injury or disease.
Hydrocephalus may also be communicating or non-communicating. Communicating hydrocephalus occurs when the flow of CSF is blocked after it exits the ventricles. This form is called communicating because the CSF can still flow between the ventricles, which remain open. Non-communicating hydrocephalus - also called "obstructive" hydrocephalus - occurs when the flow of CSF is blocked along one or more of the narrow passages connecting the ventricles. One of the most common causes of hydrocephalus is "aqueductal stenosis." In this case, hydrocephalus results from a narrowing of the aqueduct of Sylvius, a small passage between the third and fourth ventricles in the middle of the brain.
There are two other forms of hydrocephalus which do not fit exactly into the categories mentioned above and primarily affect adults: hydrocephalus ex-vacuo and normal pressure hydrocephalus.
Hydrocephalus ex-vacuo occurs when stroke or traumatic injury cause damage to the brain. In these cases, brain tissue may actually shrink. Normal pressure hydrocephalus can happen to people at any age, but it is most common among the elderly. It may result from a subarachnoid hemorrhage, head trauma, infection, tumor, or complications of surgery. However, many people develop normal pressure hydrocephalus even when none of these factors are present for reasons that are unknown.
What are the symptoms for hydrocephalus?
The signs and symptoms of hydrocephalus vary somewhat by age of onset.
Common signs and symptoms of hydrocephalus in infants include:
Changes in the head
- An unusually large head
- A rapid increase in the size of the head
- A bulging or tense soft spot (fontanel) on the top of the head
Physical signs and symptoms
- Poor feeding
- Eyes fixed downward (sunsetting of the eyes)
- Deficits in muscle tone and strength
- Poor responsiveness to touch
- Poor growth
Toddlers and older children
Among toddlers and older children, signs and symptoms may include:
Physical signs and symptoms
- Blurred or double vision
- Eyes fixed downward (sunsetting of eyes)
- Abnormal enlargement of a toddler's head
- Sleepiness or lethargy
- Nausea or vomiting
- Unstable balance
- Poor coordination
- Poor appetite
- Urinary incontinence
Behavioral and cognitive changes
- Change in personality
- Decline in school performance
- Delays or problems with previously acquired skills, such as walking or talking
Young and middle-aged adults
Common signs and symptoms in this age group include:
- Loss of coordination or balance
- Loss of bladder control or a frequent urge to urinate
- Impaired vision
- Decline in memory, concentration and other thinking skills that may affect job performance
Among adults 60 years of age and older, the more common signs and symptoms of hydrocephalus are:
- Loss of bladder control or a frequent urge to urinate
- Memory loss
- Progressive loss of other thinking or reasoning skills
- Difficulty walking, often described as a shuffling gait or the feeling of the feet being stuck
- Poor coordination or balance
When to see a doctor
Seek emergency medical care for infants and toddlers experiencing these signs and symptoms:
- A high-pitched cry
- Problems with sucking or feeding
- Unexplained, recurrent vomiting
- An unwillingness to move the head or lay down
- Breathing difficulties
Seek prompt medical attention for other signs or symptoms in any age group.
Because more than one condition can result in the problems associated with hydrocephalus, it's important to get a timely diagnosis and appropriate care.
What are the causes for hydrocephalus?
Hydrocephalus is caused by an imbalance between how much cerebrospinal fluid is produced and how much is absorbed into the bloodstream.
Cerebrospinal fluid is produced by tissues lining the ventricles of the brain. It flows through the ventricles by way of interconnecting channels. The fluid eventually flows into spaces around the brain and spinal column. It's absorbed primarily by blood vessels in tissues near the base of the brain.
Cerebrospinal fluid plays an important role in brain function by:
- Keeping the brain buoyant, allowing the relatively heavy brain to float within the skull
- Cushioning the brain to prevent injury
- Removing waste products of the brain's metabolism
- Flowing back and forth between the brain cavity and spinal column to maintain a constant pressure within the brain — compensating for changes in blood pressure in the brain
Excess cerebrospinal fluid in the ventricles occurs for one of the following reasons:
- Obstruction. The most common problem is a partial obstruction of the normal flow of cerebrospinal fluid, either from one ventricle to another or from the ventricles to other spaces around the brain.
- Poor absorption. Less common is a problem with the mechanisms that enable the blood vessels to absorb cerebrospinal fluid. This is often related to inflammation of brain tissues from disease or injury.
- Overproduction. Rarely, cerebrospinal fluid is created more quickly than it can be absorbed.
What are the treatments for hydrocephalus?
One of two surgical procedures can be used to treat hydrocephalus
The most common treatment for hydrocephalus is the surgical insertion of a drainage system, called a shunt. It consists of a long, flexible tube with a valve that keeps fluid from the brain flowing in the right direction and at the proper rate.
One end of the tubing is usually placed in one of the brain's ventricles. The tubing is then tunneled under the skin to another part of the body — such as the abdomen or a heart chamber — where the excess fluid can be more easily absorbed.
People who have hydrocephalus usually need a shunt system for the rest of their lives. They require regular monitoring.
Endoscopic third ventriculostomy
Endoscopic third ventriculostomy is a surgical procedure that can be used for some people. The surgeon uses a small video camera see inside the brain. Your surgeon makes a hole in the bottom of one of the ventricles or between the ventricles to enable cerebrospinal fluid to flow out of the brain.
Complications of surgery
Both surgical procedures can result in complications. Shunt systems can stop draining cerebrospinal fluid or poorly regulate drainage because of mechanical problems, blockage or infections. Complications of ventriculostomy include bleeding and infections.
Any failure requires prompt attention, surgical revisions or other interventions. Fever or recurrence of the original symptoms of hydrocephalus should prompt an appointment with your doctor.
Some people with hydrocephalus, particularly children, might need additional treatment, depending on the severity of long-term complications of hydrocephalus.
Children's care teams might include the following:
- Pediatrician or physiatrist, who oversees the treatment plan and medical care
- Pediatric neurologist, who specializes in the diagnosis and treatment of neurological disorders in children
- Occupational therapist, who specializes in therapy to develop everyday skills
- Developmental therapist, who specializes in therapy to help your child develop age-appropriate behaviors, social skills and interpersonal skills
- Mental health professional, such as a psychologist or psychiatrist
- Social worker, who assists the family with getting needed services and planning for transitions in care
Children who are in school will likely need special education teachers, who address learning disabilities, determine educational needs and identify needed resources.
Adults with more-severe complications also might need the services of occupational therapists, social workers, specialists in dementia care or other medical specialists.
What are the risk factors for hydrocephalus?
In many cases, the exact event leading to hydrocephalus is unknown. However, a number of developmental or medical problems can contribute to or trigger hydrocephalus.
Hydrocephalus present at birth (congenital) or shortly after birth may occur because of any of the following:
- Abnormal development of the central nervous system that can obstruct the flow of cerebrospinal fluid
- Bleeding within the ventricles, a possible complication of premature birth
- Infection in the uterus during a pregnancy, such as rubella or syphilis, that can cause inflammation in fetal brain tissues
Other contributing factors
Other factors that can contribute to hydrocephalus among any age group include:
- Lesions or tumors of the brain or spinal cord
- Central nervous system infections, such as bacterial meningitis or mumps
- Bleeding in the brain from a stroke or head injury
- Other traumatic injury to the brain
Is there a cure/medications for hydrocephalus?
People who have hydrocephalus usually need a shunt system for the rest of their lives. They require regular monitoring. Children who are in school will likely need special education teachers, who address learning disabilities, determine educational needs and identify needed resources. Adults with more-severe complications also might need the services of occupational therapists, social workers, specialists in dementia care or other medical specialists.