Hydrocephalus, also called Water on the Brain is a condition in which there is an abnormal build up of CSF (cerebrospinal fluid) in the cavities (ventricles) of the brain. The buildup is often caused by an obstruction which prevents proper fluid drainage. The fluid buildup can raise intracranial pressure inside the skull which compresses surrounding brain tissue, possibly causing progressive enlargement of the head, convulsions, and brain damage. Hydrocephalus can be fatal if left untreated.
The damage to the brain can cause headaches, vomiting, blurred vision, cognitive problems, and walking difficulties.
The term water on the brain is incorrect, because the brain is surrounded by CSF (cerebrospinal fluid), and not water. CSF has three vital functions:
- It protects the nervous system (brain and spinal cord) from damage
- It removes waste from the brain
- It nourishes the brain with essential hormones.
The brain produces about 1 pint of CSF each day. The old CSF is absorbed into blood vessels. If the process of replenishment and release of old CSF is disturbed, CSF levels can accumulate, causing hydrocephalus.
There are three types of hydrocephalus:
1) Congenital hydrocephalus
This is present at birth. According to the National Health Service (UK), approximately 1 in every 1,000 babies are born with congenital hydrocephalus, while The Mayo Clinic, USA, says 1 in every 500 US babies are born with it. It may be caused by an infection in the mother during pregnancy, such as rubella or mumps, or a birth defect, such as spina bifida. It is one of the most common developmental disabilities, more common than Down syndrome or deafness.
2) Acquired hydrocephalus
3) Normal pressure hydrocephalus
This only affects people aged 50 years or more. It may develop after stroke or injury. In most cases doctors do not know why it occurred. 2 in every 100,000 people are affected by normal pressure hydrocephalus in England each year.
According to the National Institutes of Health (NIH), USA, approximately 700,000 American children and adults live with hydrocephalus. Hydrocephalus is also the leading cause of brain surgery for children in the USA. The NIH adds that over the past 25 years death rates linked to hydrocephalus have dropped from 54% to 5%, while the occurrence of intellectual disability has dropped from 62% to 30%.
The NIH says there are more than 180 different possible causes of hydrocephalus; a common cause being brain hemorrhage linked to premature birth.
A prenatal ultrasound examination can sometimes detect hydrocephalus in the developing baby.
The outlook for a patient with hydrocephalus depends mainly on how quickly the condition is diagnosed and treated, and whether there are any underlying disorders.
Treatment for hydrocephalus often involves using a shunt - a thin tube that is implanted in the brain to drain away excess cerebrospinal fluid (CSF).
Symptoms of hydrocephalus
A symptom is something the patient senses and describes, while a sign is something other people, such as the doctor notice. For example, drowsiness may be a symptom, while dilated pupils may be a sign.
Symptoms of congenital hydrocephalus (present at birth):
- Breathing difficulties.
- Muscles in the baby's arms and legs may be stiff and prone to contractions.
- Some of the developmental stages may be delayed, such as sitting up or cradling.
- Tense fontanelle - an outward curving of an infant's soft spot (fontanelle). The soft part of the top of the baby's head bulges outwards.
- The baby may be irritable and/or drowsy
- The baby may be unwilling to bend or move his/her neck or head.
- The baby may feed poorly.
- The baby's head seems larger than it should be.
- The baby's scalp is thin and shiny. There may be visible veins on the scalp.
- The pupils of the baby's eyes may be right close to the bottom of the eyelid; sometimes known as the setting sun.
- There may be a high-pitched cry.
- There may be seizures.
- There may be vomiting.
Symptoms of acquired hydrocephalus (develops after birth):
- Bowel incontinence (rare)
- Confusion and/or disorientation
- Irritability, which may be progressive
- Lack of appetite
- Personality changes
- Problems with eyesight, such as blurred or double vision
- Seizures (fits)
- Urinary incontinence
- Walking difficulties (more common in adults).
Symptoms of normal pressure hydrocephalus (affects people aged 50+) - signs and symptoms may take many months or years to develop.
- Changes in gait - the patient may feel as if they are frozen on the spot when taking their first step to start walking. The individual may appear to shuffle rather than walk.
- Normal thinking process slows down - the patient may respond to questions more slowly than normal, there may be delayed reactions to situations. The individual's ability to process information slows down.
- Urinary incontinence - this usually comes after changes in gait.
Risk factors for hydrocephalus
A risk factor is something which increases the likelihood of developing a condition or disease. For example, obesity significantly raises the risk of developing diabetes type 2. Therefore, obesity is a risk factor for diabetes type 2. The following are possible risk factors for hydrocephalus:
- Being born prematurely - infants born prematurely have a higher risk of intraventricular hemorrhage (bleeding within the ventricles of the brain), which may result in hydrocephalus.
- Problems during pregnancy - an infection in the uterus during pregnancy may increase the risk of hydrocephalus in the developing baby.
- Problems with fetal development, such as incomplete closure of the spinal column. Some congenital defects may not be detectable at birth - but the baby may be at increased risk of developing hydrocephalus when he/she is older (still during childhood).
- Lesion and tumors of the spinal cord or brain.
- Infections of the nervous system.
- Bleeding in the brain.
- Having a severe head injury.
On the next page we look at the causes of hydrocephalus (water on the brain) and how the condition can be diagnosed. On the final page we discuss treatments for hydrocephalus and methods of prevention.