What is Hydrocephalus?
Hydrocephalus comes from the Greek words: “Hydro” meaning water and “cephalus” meaning head.
Hydrocephalus is a chronic, neurological condition caused by an abnormal accumulation of cerebrospinal fluid (CSF) within cavities of the brain called ventricles, resulting in pressure on the brain. It affects over 1 million Americans, ranging from infants and older children to young and middle-aged adults, as well as seniors. There is currently no cure for hydrocephalus, but it can be treatable.
CSF is produced in the ventricles and in the choroid plexus. It circulates through the ventricular system in the brain and is absorbed into the bloodstream. CSF is in constant circulation and has many functions. It surrounds the brain and spinal cord and acts as a protective cushion against injury. CSF contains nutrients and proteins that are needed for the nourishment and normal function of the brain. It carries waste products away from surrounding tissues.
Hydrocephalus occurs when there is an imbalance between the amount of CSF that is produced and the rate at which it is absorbed. As the CSF builds up, it causes the ventricles to enlarge and the pressure inside the head to increase.
For more detailed information, visit Cerebrospinal Fluid Dynamics Relevant to Hydrocephalus.
Types and Causes of Hydrocephalus
Hydrocephalus is a complex, chronic condition. It can develop for a variety of reasons, sometimes as part of another condition. You can be born with it, acquire it from some brain tumors, infections of the brain, and brain injury. It may also develop it as part of the aging process.
In the United States, 1 in every 770 babies develops hydrocephalus. Hydrocephalus that is present at birth is referred to as congenital hydrocephalus. Hydrocephalus that develops later in life in some children, and even in adults, but is caused by a condition that existed at birth, is still considered a form of congenital hydrocephalus. Congenital hydrocephalus is caused by a complex interaction of genetic and environmental factors during fetal development. The most common causes of congenital hydrocephalus are:
- Spina bifida
- Aqueductal stenosis
- Brain malformations
Acquired hydrocephalus is the form of hydrocephalus that develops after birth. Both children and adults can be diagnosed with acquired hydrocephalus. The most common causes are:
- Head injuries
- Brain tumors
- Intraventricular hemorrhage (brain bleed), commonly as a complication of prematurity
- Meningitis or other infection of the brain or spinal cord
There are other classifications that you might hear when talking to your doctor particularly around the time of diagnosis. These can include:
- Compensated or arrested hydrocephalus
- Communicating hydrocephalus
- Non-communicating hydrocephalus, also known as obstructive hydrocephalus
For more detailed information, visit Types and Causes.
Normal pressure hydrocephalus (NPH) occurs in older adults, typically diagnosed in individuals 60 and older. Normal pressure hydrocephalus is an accumulation of CSF that causes the ventricles in the brain to become enlarged, but there is little or no increase in the pressure within the ventricles. In most cases of NPH, the cause of blockage to the CSF absorptive pathways is unclear.
Primary NPH: Many NPH diagnoses are considered idiopathic, which means that the cause is unknown. These are also referred to as primary NPH.
Secondary NPH: When NPH results from a known cause it is referred to as secondary NPH. Secondary NPH can be diagnosed as the result of a head injury, cranial surgery, subarachnoid hemorrhage, tumor or cysts, as well as subdural hematomas, bleeding during surgery, meningitis, and other brain infections.
What are the symptoms of Hydrocephalus?
The symptoms of untreated hydrocephalus vary. However, here are some overarching signs and symptoms of the condition:
- For pregnant women, an ultrasound may detect enlarged ventricles, indicating the possible presence of hydrocephalus.
- In an infant, the most obvious sign of hydrocephalus is an abnormal enlargement of the baby’s head. Additional symptoms include vomiting, sleepiness, bulging soft spot, and downward deviation of the baby’s eyes (the sun setting eyes).
- In children, due to raised intracranial pressure (ICP), symptoms may include nausea, vomiting, headaches, and vision problems.
- In young and middle-aged adults, symptoms reported include, but are not limited to, vision problems, balance and coordination issues, disturbances in gait, fatigue, chronic headaches, vertigo, syncope (fainting), nausea, and short term memory issues.
- In older adults with NPH, the symptoms are likely to be decreased in normal functioning in three main areas: gait disturbances (walking and standing), cognitive abilities (mild dementia, forgetfulness, or loss of interest), and impairment in bladder control.
Diagnosis of Hydrocephalus
A diagnosis is made by using brain imaging techniques such as ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), and a thorough neurological evaluation during a doctor visit. More tests are often performed in adults in order to diagnose the condition. These tests may include lumbar puncture, continuous lumbar CSF drainage, intracranial pressure (ICP) monitoring, measurement of cerebrospinal fluid outflow resistance, or isotopic cisternography. A neuropsychological evaluation may also be recommended. The decision to order a particular test may depend on the specific clinical situation, as well as the preference and experience of the medical team.
Not all of the tests listed are required in order to make a diagnosis.
Is Hydrocephalus treatable?
With early detection and appropriate intervention, the future for many is promising. Currently, the only form of treatment for hydrocephalus requires brain surgery. There are three forms of surgical treatment used to manage hydrocephalus.
- Shunt: The most common treatment for hydrocephalus is a medical device called a shunt, a flexible tube, which is placed in the ventricular system of the brain that diverts the flow of CSF to another region of the body, most often the abdominal cavity, or heart, where it can be absorbed.
- Endoscopic Third Ventriculostomy (ETV): A second surgical treatment option is called an ETV. With this procedure, an endoscope is used to puncture a membrane on the floor of the third ventricle. This creates a pathway for CSF to exit the ventricular system and a shunt may not be needed. This procedure is typically performed in children over the age of 2. Not everyone is a candidate for ETV treatment.
- Endoscopic Third Ventriculostomy (ETV) with Choroid Plexus Cauterization (CPC): The third treatment option involves the addition of choroid plexus cauterization (CPC) with ETV as a treatment primarily in children under 2. The neurosurgeon uses a device to burn or cauterize choroid plexus tissue to reduce the amount of fluid being introduced into the ventricles. The choroid plexus is vascular tissue within the ventricles of the brain and is the source of CSF production. The fluid then passes normally through the opening made during the ETV and into the space surrounding the surface of the brain. Not everyone is a candidate for ETV/CPC treatment. ETV/CPC is a very technical surgery and should be performed by a neurosurgeon trained and experienced in the procedure.
Management of Hydrocephalus
It is important to understand that life with a shunt or ETV does require you to always be well informed and vigilant about complications. While some people can go 20 years or more without a complication, with a complex condition like hydrocephalus, things can change quickly therefore it’s critical to be prepared.
Complications of a Shunt and an ETV
When things are going well, it’s easy to put the concerns about hydrocephalus and the complications that come with it out of your mind. However, shunts can malfunction, fail, or become infected and this requires a shunt revision, which requires brain surgery. An ETV can close at any time and put an individual in an emergency situation. It is critical to understand the signs and symptoms of shunt failure or the closure of an ETV in order to respond quickly.
Seeking immediate medical attention can identify a resolvable complication and enable you or your family member to avoid brain damage or even death.
What is the Prognosis?
Investments in research and advances in technology, as well as diagnostic and treatment protocols, are helping more and more people with hydrocephalus to lead full and active lives. However, it is a complex condition and the long-term effects of hydrocephalus can vary greatly from person to person. Some general problems we see across our patient population include but are not limited to learning challenges, problems with vision, short term memory issues, executive function challenges, and chronic headaches and pain. It is also important to know that hydrocephalus is still fatal if left untreated or from complications that can arise from treatment.
You’re not alone. The journey with hydrocephalus can be challenging and unpredictable. We provide essential tools and resources that enable you to have more control of your life. There is a large community across the country that is engaged and connected through the Hydrocephalus Association, ready to support you and your family. By staying well informed and planning appropriately, you or your loved one can realize their dreams of graduating from high school, attending college, pursuing a career, getting married, having a family, and enjoying retirement.
Research and Hydrocephalus
As the leading private funder of hydrocephalus research in the country, we are investing in research to improve outcomes as well as prevent the development of hydrocephalus and, ultimately, find a cure.
You can be a part of research. Enroll in HAPPIER, the only hydrocephalus patient-powered registry in the country, and help our doctors and scientists better serve you!
The Hydrocephalus Association regularly supports our scientists and doctors by assisting in gathering data through surveys as well as through helping enroll patients in current research studies.
Information you can trust! This article was produced by the Hydrocephalus Association, copyright 2021. We would like to thank the following individuals for their valuable contributions and expert input: Marion L. (Jack) Walker, MD, and Cathy Cartwright, DNP, RN-BC, PCNS, FAAN.