Hydrocephalus

Hydrocephalus is a condition where there is excess accumulation of cerebrospinal fluid (CSF) occurs within the ventricles of the brain which in turn puts pressure on the brain’s tissues.

Hydrocephalus baby

What is Cerebrospinal fluid?

Cerebrospinal fluid (CSF) is the clear, colorless fluid that protects and cushions the brain and spine.  

Normal flow of CSF

Normally, cerebrospinal fluid flows through the ventricles and bathes the brain and spinal cord before being reabsorbed into the bloodstream. The body typically produces enough CSF each day and absorbs the same amount. 

Hydrocephalus

Abnormal CSF flow

When the normal flow or absorption of CSF is blocked it can result in a buildup of CSF. 

Effects of increase CSF pressure

The pressure from too much CSF can keep the brain from functioning properly and cause brain damage and even death.

Types of hydrocephalus

Hydrocephalus can affect anyone at any age but is most common in infants and older adults.  Some of these cases can be associated with abnormalities in the brain and spinal cord during pregnancy.  

The two major types of hydrocephalus are called communicating hydrocephalus and non-communicating hydrocephalus.

Communicating hydrocephalus occurs when the flow of CSF is blocked after it exits the ventricles as the CSF flow is normal between the ventricles of the brain.

• Non-communicating hydrocephalus happens when the flow of CSF is blocked along one or more of the narrow passages connecting the ventricles.  

MRI hydrocephalus

Two additional types of hydrocephalus include:

• Hydrocephalus ex-vacuo results from brain damage caused by stroke or injury which is not a true hydrocephalus, but rather, a “hydrocephalus look-alike” condition.
• Normal Pressure Hydrocephalus (NPH) can be the result of bleeding in the brain’s CSF (subarachnoid or intraventricular hemorrhage), head trauma, infection, tumor, or a complication of surgery. 

Incidence

The number of people who develop hydrocephalus or that currently living with it is difficult to establish since the condition occurs in children and adults, and can develop later in life. Some estimates report one to two of every 1,000 babies are born with hydrocephalus.

Causes of hydrocephalus

Hydrocephalus may be present at birth (congenital) or may develop over time as a result of injury or disease (acquired).  Except for hydrocephalus secondary to physical obstruction of CSF passages within the brain or skull by blood or tumor, the exact causes of hydrocephalus are still not well understood.

Congenital hydrocephalus 

Babies may be born with Communicating hydrocephalus hydrocephalus or develop the condition shortly after delivery.  In these cases, hydrocephalus may be caused by:

• inherited genetic abnormalities that block the flow of CSF
• developmental disorders such as those associated with birth defects in the brain, spine, or spinal cord
• complications of premature birth such as bleeding within the ventricles
• infection during pregnancy such as rubella that can cause inflammation in the fetal brain tissue.

Acquired hydrocephalus 

Certain factors can increase the risk of developing hydrocephalus at any age, including:

• brain or spinal cord tumors
• infections of the central nervous system such as bacterial meningitis
• injury or stroke that causes bleeding in the brain.

Hydrocephalus with sunset eyes

Symptoms

• Eyes that appear to gaze downward
• Irritability
• Seizures
• Separated sutures
• Sleepiness
• Brief, shrill, high-pitched cry

Symptoms in older children and adults

• Changes in personality, memory, or the ability to reason or think
• Changes in facial appearance and eye spacing (craniofacial disproportion)
• Crossed eyes or uncontrolled eye movements (Sunset eyes)
• Difficulty feeding
• Excessive sleepiness
• Headaches
• Loss of bladder control (urinary incontinence)
• Loss of coordination and trouble walking
• Muscle spasticity (spasm)
• Slow growth (child 0–5 years)
• Delayed milestones
• Failure to thrive
• Slow or restricted movement
• Vomiting

Normal pressure hydrocephalus versus atrophy

Investigations

Brain imaging and other tests

Tests to accurately diagnose hydrocephalus and rule out other conditions may include:

• Ultrasound
• Magnetic resonance imaging (MRI)
• Computed tomography (CT)
• Spinal tap (lumbar puncture)
• Intracranial pressure monitoring (ICP)
• Fundoscopic examination

Treatment options

Surgical treatments for hydrocephalus 

Hydrocephalus Shunt Child

Hydrocephalus is treated with one of two surgical options:

• A shunt (tube) is surgically inserted into the brain and connected to a flexible tube placed under the skin to drain the excess fluid into either the chest cavity or the abdomen so it can be absorbed by the body.
• Endoscopic Third Ventriculostomy (ETV) improves the flow of CSF out of the brain.   A tiny hole is made at the bottom of the third ventricle and the CSF is diverted there to relieve pressure.  Sometimes this is done in conjunction with choroid plexus cauterization to try and decrease the production of CSF.  Choroid plexus cauterization uses electric current to burn the CSF-producing tissue (i.e., the choroid plexus) in the lateral ventricles in the brain, so it produces less CSF.

Other treatments 

• occupational and developmental therapists who can help children learn life skills and develop social behaviors
• special education teachers who can help tackle learning disabilities
• mental health providers or social workers who can provide emotional support and help families find services.

Adults may also require similar support, including social workers, occupational therapists, and specialists in dementia care.

Prognosis

• If left untreated, hydrocephalus can be fatal. 
• With the benefits of surgery, rehabilitative therapies, and educational interventions, many people with hydrocephalus live relatively normal lives.
• The symptoms of NPH usually get worse over time if the condition is not treated, although some people may experience temporary improvements.
• While the success of treatment with shunts varies from person to person, some people recover almost completely after treatment and have a good quality of life.

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