Today those diagnosed with hydrocephalus during infancy are given a good prognosis due to an amazing mechanical device called a shunt. Because of the shunt most children will develop relatively normal intelligence and be able to live normal lives.  The risks of damage to the central nervous system are reduced by draining the cerbrospinal fluid away from the brain therefore stabilizing the intracranial pressure.  Unfortunately, those needing shunts are prone to multiple problems related to shunt dependency and malfunction.  As noted by Drs. Drake and Sainte-Rose, shunts are only a temporary solution for a permanent condition.

As quoted by Drs. Drake and Sainte-Rose:  For inherent technical reasons, it is probable that a "shunt forever" is an impossible dream, but delaying shunt malfunction as long as possible is a realistic goal.

Shunt Revision

When a shunt system needs to be replaced, the operation is referred to as a revision.  Which simply mean to change or modify.  When a shunt is first put in place, it is the dream of the neurosurgeon and patient that the shunt will last forever.  Unfortunately, shunts do not last forever and it is unrealistic to think they ever will.  Shunts are susceptible to failures and malfunctions, just like any other mechanical device.  Reasons why a shunt may need to be revised:

*  Mechanical failures such as the valve has failed to work correctly.

*  Use of the wrong type of shunt valve

*  Infections*  Obstructions*  Need to lengthen or replace the distal catheter or valve.

Signs of Possible Shunt Complications

If a shunt system fails to operate correctly, becomes infected, or obstructed, the patients life and cognitive faculties are placed at risk.  Often times the must be revised under emergency conditions.  Most signs and symptoms are identical to those at diagnosis.  Other symptoms may relate to a particular type of shunt placement.  The signs and symptoms are:

*  Loss of appetite.

*  Nausea and vomiting

*  Behavioral changes, irritability.

*  Frequent or persistent headaches with increased severity.

*  Gait difficulties such as frequent loss of balance or mobility, stumbling, or drifting to one side or the other while walking.

*  Lethargy, defined as a sudden loss of energy, complaining all the time of being tired, or having an extremely difficult time walking.

*  Reduced or impaired cognitive ability.

*  Inability to process thoughts or perform routine tasks without getting disoriented.

*  Loss of memory or signs of dementia.

*  Vision problems, including impaired or double vision, and crossed or wondering eyes.

*  Loss of upward gaze (sunsetting of the eyes).

*  Impaired or slurred speech.

*  A persistent low grade fever usually greater than 100 degrees Fahrenheit/38 degrees Celsius or a high grade fever 102-104 degrees Fahrenheit/39-40 degrees Celsius if the infection is more aggressive.

*  Redness or swelling along the shunt tract.

*  Tenderness in the areas surrounding the shunt system, including the abdomen

*  Coma

*  Difficulty in breathing (with VP1 shunts)

*  Cardiac arrhythmia (abnormal heart rate)

Symptoms should be taken seriously, especially if you notice two or more at the same time.  Neurological status can deteriorate slowly (over a few months) or quite rapidly ( few hours or days).  Therefore, when symptoms of a possible problem with a shunt begin to slow, it is imperative that you seek medical attention immediately.

Obstructions

Obstructions are the most common shunt complications and are either in the proximal or distal catheters.  The proximal catheter is the most likely to be obstructed.  When CSF is drawn into the shunt system, the catheter creates a suction effect within the ventricle.  This suction could possibly draw the choroid plexus, blood, and debris toward the holes at the end of the catheter and contribute to obstruction.

The proximal catheter can be obstructed by a variety of factors, including:

*  In-Growth by the choroid plexus

*  Collapsed ventricles, which occlude the holes at the end of the ventricular catheter.

*  Blood clots resulting from hemorrhaging during placement or removal of the ventricular catheter.

*  Buildup of tissue debris.

The distal catheter becoming obstructed is less common, but it can occur.  Distal catheters for VP shunts can be obstructed if debris in the peritoneal cavity accumulates around the tip of the catheter.  Loss of absorptive ability by peritoneal cavity or the growth of peritoneal pseudocysts also contribute to distal catheter obstructions.  VA shunts can become obstructed when the distal catheter migrates out of the right atrium of the heart and lies against the wall of the superior vena cava.

Shunt Infection

Shunt infections are the most serious complication related to the treatment of hydrocephalus.  They most commonly occur within one to two months following a placement or revision procedure.  It is also known that infection represents the most expensive burden of CSF shunt implantation; an average of 8-45 thousands of dollars are needed for each treated patient.  The most common germs involved in early shunt infections are Staphylococcus Epidermidis and Staphylococcus Aureus; these bacteria may enter during surgery, from hair follicles and/or sebaceous glands opened by the surgical incision.

Symptoms of Shunt Infections

*  A persistent low grade fever usually greater than 100 degrees Fahrenheit/38 degrees Celsius or a high grade fever 102-104 degrees Fahrenheit/39-40 degrees Celsius if the infection is more aggressive.

*  Irritability and changes in mood or personality.

*  Changes in cognitive ability.

*  Redness and/or tenderness along the shunt tract.

*  Swelling or tenderness of the abdomen (with VP shunt)

*  Sudden, frequent vomiting or persistent nausea.

*  Headaches.

*  Soreness of the neck and/or shoulder muscles.

Any of the above symptoms, especially in combination with a high fever, could indicate the possibility that something is wrong.  If you suspect a shunt infection, contact you primary care physician or neurosurgeon immediately.

What Causes Shunt Infections?

*  Bacteria being introduced to one of the incisions during surgery.

*  Placement of an improperly sterilized shunt valve or catheter.

*  An infection near the distal end of the shunt system, such as peritonitis for VP shunt placements.  An infection near the distal end is also referred to as a pseudocyst, which is a collection of infected fluid that forms a cyst around the tip of the distal catheter.

*  Length of time the shunt procedure takes.  The longer the procedure, the greater risk for infection.

Treating Shunt Infections

Treatment of shunt infections is usually a long process requiring hospitalization.  When you have a shunt infection you are placed on high doses of intravenous antibiotics to fight off the infection.  The entire shunt system is removed to prevent any possibility of reintroducing the infection to your body.  Because the shunt system , in most cases must be removed, the CSF will be drained through an external ventricle drainage (EVD) system.  An EVD consists of a ventricular catheter, a shunt valve, and a bag which collects CSF at the distal end. With the EVD system you will continue to receive intravenous antibiotics until further tests of CSF indicate that the infection is gone.  This could take anywhere from two to fourteen days.  After the CSF has been proven to be sterile for seven to fourteen days, your neurosurgeon will insert a new shunt system.