"Fluid/Water On The Brain"
What is Hydrocephalus?
Hydrocephalus is a condition in which excess fluid builds up in the ventricles (cavities) and subarachnoid space within the brain. The brain’s ventricular system transports cerebrospinal fluid (CFS) through an internal part comprised of four chambers (ventricles) and an external part including the subarachnoid space. This colorless fluid is produced in the brain’s lateral ventricles and has three main functions:
- Protecting the brain and spinal cord from injury
- Providing nutrients to tissue throughout the nervous system
- Removing waste matter from the brain
When excess CFS builds up in the brain’s cavities, it causes them to widen, which puts harmful pressure on the brain.
Hydrocephalus can affect anyone, although it is more common in infants and adults over the age of 60. One out of every 1,000 infants is born with this condition. The only way to treat hydrocephalus is with surgery.
Cerebrospinal Fluid (CSF)
Ventricles of the Brain
Types of Hydrocephalus
There are also two subcategories of hydrocephalus, these are:
- Communicating hydrocephalus: this form of hydrocephalus prevents CFS from being properly absorbed into the bloodstream resulting in an excess of fluid in the ventricular system. This is caused by a clog in the arachnoid granulations which are the modes that CFS is diffused into the dural venous sinus (veins) located in the dura mater. This clog can be caused by hemorrhage (due to red blood cells), infection, or inflammation. Communicating hydrocephalus is also known as nonobstructive hydrocephalus because while it inhibits CFS fluid in the ventricular system from being adequately reabsorbed into the veins, it still allows the fluid to flow between the brain's ventricles and the subarachnoid space.
- Non-communicating hydrocephalus: Also known as obstructive hydrocephalus, in this form, CFS is blocked from flowing between the brain’s ventricles and the subarachnoid space.
There are several different types of hydrocephalus. These include:
- Normal-pressure hydrocephalus: This form of communicating hydrocephalus occurs when CFS builds up in the ventricles of the brain but causes little or no pressure on the brain.
- Congenital hydrocephalus: This form of hydrocephalus is rare. It occurs when CFS builds up in the brain during birth. The increased pressure on the baby’s brain can lead to brain damage if not treated quickly.
- Hydrocephalus ex vacuo: This form of hydrocephalus occurs when the brain has suffered trauma. The volume of CFS is higher than normal but the pressure on the brain is not higher than normal.
- Acquired hydrocephalus: This form of hydrocephalus can occur at any time after birth.
- Compensated hydrocephalus: This condition occurs when hydrocephalus was present at birth but did not show any symptoms until later in life.
Layers of the Meninges
Signs and symptoms of hydrocephalus in infants include:
- Bulging fontanelles - the soft spots at the crown and back of a baby’s head
- A sudden increase in the circumference of the baby’s head
- Downward-looking eyes
- Restlessness and crying
- Difficulty feeding
- Excessive sleeping
Signs and symptoms of hydrocephalus in childhood include:
- Nausea and vomiting
- Difficulty standing or walking
- Blurred vision
- Memory issues
- Difficulty controlling the bladder
- Changes in personality
Symptoms of adult-onset hydrocephalus include:
- Shuffling or difficulty walking
- Blurred vision
- Weakness in the legs
- Bladder incontinence
- Mood and personality changes
The cause of hydrocephalus varies depending on the type.
Causes of Congenital Hydrocephalus
- Aqueductal stenosis: This is the most common cause of congenital hydrocephalus. It involves the narrowing or blockage of an area of the brain known as the Cerebral Aqueduct (Aqueduct of Sylvius) – a narrow tube between the third and fourth ventricles in the brain (see picture below). It may become blocked due to certain types of bacterial, viral or parasitic infections, tumors, chiari malformation, or abnormal brain development.
- Neural tube defect: In a developing embryo, the neural tube is the structure that, in a healthy child, forms the brain and spinal cord. In cases of neural tube defect (NTD), the neural tube fails to close properly, leaving the spinal cord exposed. In some cases, this can cause leakage of CSF.
Causes of Acquired Hydrocephalus
- Bleeding within the brain: In premature newborns, small blood vessels in the brain’s ventricles can hemorrhage, causing blockages or scar tissue. This can cause a build-up of CSF.
- Meningitis: This is an infection that damages the membranes protecting the brain and spinal cord, usually by a bacterial infection.
- Injury to the head: Trauma to the head can cause damage to tissues and blood vessels, which can lead to a build-up of CSF.
- Certain types of brain tumor: In infants, if brain tumors occur, they typically develop in the back of the brain. This type of tumor may cause hydrocephalus by blocking the brain’s fourth ventricle.
Causes of Compensated Hydrocephalus
Compensated hydrocephalus is sometimes seen in elderly people who are suffering from brain diseases such as Alzheimer’s. It occurs when the brain begins to shrink.
Causes of Normal-Pressure Hydrocephalus
In many cases of normal-pressure hydrocephalus, the cause is not known (idiopathic). In other cases, it may be due to brain injury, certain types of tumors, inflammation, or an infection.
Causes of Hydrocephalus ex Vacuo
Hydrocephalus ex vacuo is caused when the brain has been damaged due to trauma or stroke, causing a build-up of CSF.
Hydrocephalus Risk Factors
Often hydrocephalus can not be traced back to its original cause. However, several medical problems are known to be possible triggers for this condition.
Risk factors for hydrocephalus which occurs at or shortly after birth (congenital hydrocephalus) may be increased by:
- Abnormal development of the fetal brain or spinal cord, such as neural tube defect, or spina bifida. Spina bifida is a type of neural tube defect in which there is abnormal development in the spine and spinal cord.
- Hemorrhage of the ventricles in the brain, which may be a complication of premature birth.
- A uterine infection, such as syphilis or rubella, during pregnancy.
Risk factors that can trigger hydrocephalus beyond childhood include:
- Tumors affecting the brain or spinal cord
- Infections which affect the central nervous system, such as meningitis
- Traumatic injury to the brain
- Bleeding in the brain due to a stroke
After discussing your medical history and symptoms, your doctor will order a scan of your brain. These imaging techniques allow your doctor to examine the ventricles in the brain to see if they are larger than normal. One of the following brain imaging techniques will be used:
- Ultrasound: This procedure uses sound waves to produce images of the brain. It is frequently used for an initial assessment for hydrocephalus. If you are pregnant, your doctor may use ultrasound to diagnose hydrocephalus during a prenatal exam.
- Magnetic resonance imaging (MRI): This is a painless test that uses radio waves and a electromagnetic field to create three-dimensional images of the brain. The MRI machine is noisy and the patient is required to lie very still during an MRI.
- Computerized tomography (CT): CT scans use X-rays to produce cross-sectional images of the brain. This test requires that the patient lies still so sedation may be given to small children or adults that fear small spaces. Because this technique does not produce images as detailed as an MRI, a CT is generally only used to diagnose hydrocephalus if an emergency examination is required.
An MRI or a CT scan can be used to diagnose hydrocephalus at any age. If the patient is an adult, your doctor will perform other tests to diagnose hydrocephalus. These may include:
- A clinical evaluation: Depending on the patient’s age, this will involve an interview and a neurological examination.
- CSF tests: These tests are performed in order to assess the patient’s responsiveness to a shunt system and to determine the shunt pressure. They may include a monitoring of intracranial pressure, lumbar puncture and drainage, isotopic cisternography, and measurement of CSF outflow resistance.
Unfortunately, there is no cure for hydrocephalus. The only treatment that is currently available is brain surgery. There are two forms of surgical management for hydrocephalus, these include:
The Ventriculoperitoneal Shunt System
This is the most common form of treatment for hydrocephalus. The procedure involves the implantation of a device called a shunt. This is a small, flexible tube which is inserted into the brain’s ventricles. The shunt contains a small valve which maintains the correct pressure within the ventricular system. The tube gathers CSF in the brain and transports it to another area of the body where it can easily be reabsorbed. The shunt exits the brain via a small hole in the skull and connects to an outflow catheter which runs under the skin to the area of the body where it will be deposited (drainage site).
Prior to the surgery, you will be given a general anesthetic. A small area behind your ear will be shaved in preparation for inserting the shunt. After making a small incision behind your ear, the surgeon will drill a small hole into your skull. A catheter will be inserted into the brain via this hole. A second catheter runs from the hole, behind your ear, to your abdomen. This tube runs under the skin and allows the unwanted CSF to drain. As the CSF pressure in your skull increases, the shunt will automatically trigger and begin draining fluid.2
Recovery takes three or four days. Typically, patients return home a week after this type of surgery.
Endoscopic Third Ventriculostomy (ETV)
This procedure is commonly used to treat obstructive hydrocephalus and aqueductal stenosis. Like shunt surgery, the aim of ETV is to divert the flow of CSF and ease pressure in the brain’s ventricular system. The main advantages ETV has over a ventriculoperitoneal shunt is that there is no need to implant anything in the brain, the surgery is less invasive, and there is a lower risk of complications following the procedure. ETV also has a quicker recovery time than the shunt surgery.
The ETV procedure is used to create a small opening at the base of the brain’s third ventricle. CSF flows from the third ventricle to the fourth ventricle through a tube called the cerebral aqueduct. When this passageway becomes constrained or blocked due to an infection, tumors, chiari malformation, or abnormal brain development this is called Aqueductal Stenosis. The burr hole in the third ventricle allows excessive CSF fluid to drain naturally into the subarachnoid cisterns (specifically the chiasmatic and interpeduncular cisterns) bypassing any obstruction in the cerebral aqueduct. Now within the subarachnoid cisterns, CSF is properly reabsorbed into the bloodstream decreasing the buildup of CSF and pressure on the brain. This procedure is suitable for child and adult patients who have been diagnosed with obstructive or non-communicating hydrocephalus.
Prior to the procedure, you will be given a general anesthetic. The surgeon will make a small incision in the scalp and insert a small endoscope (a flexible tube with a light and a camera attached). Using minute instruments, the surgeon will make a small hole in the bottom of the third ventricle. This allows the CSF to flow away from the ventricle so it can be reabsorbed into the bloodstream. After the opening has been made, the surgeon will suture the opening in the scalp.
Typically, patients remain in the hospital for two or three days after the surgery.
Endoscopic Third Ventriculostomy (ETV)
CSF flow through the brain
To learn more about Hydrocephalus and discuss your symtoms and treatment options contact us today.
The earlier hydrocephalus is diagnosed, the better the outcome will be. Recovery will depend on the type age of the patient, the type of hydrocephalus and the form of treatment. Even after surgery, it may take several months to see the full benefits. Physical, cognitive, and occupational therapy are beneficial to recovery post-surgery.
The benefits of physical therapy include:
- Improving gait and walking ability
- Increasing balance
- Helping impaired motor skills
The benefits of cognitive therapy include:
- Helping with speech
- Building thinking skills
- Improving memory
- May help learning disorders
The benefits of occupational therapy include:
- Helping with balance
- Improving coordination
- Helping with routine skills at home
FAQ - Frequently Asked Questions
Around 75,000 children and adults are discharged from American hospitals with a diagnosis of hydrocephalus.3
A majority of CSF is produced by ependymal cells (specifically epithelial cells) within the choroid plexus lining the lateral ventricles. The choroid plexus is simply a network of cells lining the ventricles which main functions are to produce CSF and prevent harmful substances from entering the brain. An adult produces roughly 650mL of CSF a day or 27mL of CSF an hour.
The meninges are the layers of membrane and tissue located in between the brain (cerebral cortex) and the skull. Subject to further subcategorization, they are broadly recognized as three layers: the pia mater (closest to the brain), arachnoid mater, and the dura mater (outer layer located right before the skull).
CSF flows from the ventricles (internal part of the ventricular system) to the subarachnoid space surrounding the brain (external part of the ventricular system). The subarachnoid space is a pocket between the pia mater (closest to the brain) and the arachnoid mater. Within the arachnoid mater there are protrusions called arachnoid granulations or villi that function as valves draining CSF into the dural venous sinus within the arachnoid mater (the tough outer layer of the meninges inside the skull that surrounds the central nervous system). The dural venous sinus drains into the jugular vein and reabsorbs the CSF into the bloodstream.
Currently, there is no way to cure hydrocephalus. The only treatment option is brain surgery to manage the symptoms.
In some cases, congenital hydrocephalus can run in families. Medical experts believe that this form of the disorder may be caused by genetic abnormalities that are passed on to the child from one or both parents.
Many infants who are born with hydrocephalus have a normal life span and between 40-50 percent have normal intelligence.4 The prognosis for adult onset of hydrocephalus will depend on the cause and the nature of the disorder.
Healthline, "Hydrocephalus (Water on the Brain)" Amanda Delgado, Valencia Higuera & Karen Gill, MD, August 2017. https://www.healthline.com/health/hydrocephalus#symptoms
Healthline, "Ventriculoperitoneal Shunt" Erica Roth & Suzanne Falck, MD, August 2017. https://www.healthline.com/health/ventriculoperitoneal-shunt#procedure
National Hydrocephalus Foundation "Facts About Hydrocephalus", October 2018. https://nhfonline.org/facts-about-hydrocephalus/
Children's Hospital of Wisconsin, "Hydrocephalus", 2019. https://chw.org/medical-care/fetal-concerns-center/conditions/infant-complications/hydrocephalus
Contact us today to if you suspect that you are having signs or symptoms of hydrocephalus. 786.871.6856