Ventricular Shunt Complications
The most common complications:
The most common complications seen in clinical practice are Mechanical Complications (shunt hardware malfunction), Over-Drainage of CSF fluid, Bleeding and Infection.
What Is A Mechanical Complication?
All shunts have three basic parts: a Ventricular Catheter, a Shunt Valve and a Distal Catheter. Any of these parts may develop sub-optimal or incomplete function. (For a more detailed explanation of a shunt, see What is a Shunt?.) If you look at the ventricular catheter closely, there are tiny holes in it which can become obstructed with tissue growing into the holes. This results in obstruction of CSF flow. Some tissue debris may block some of the holes in the catheter and/or may flow into the valve and obstruct flow through the valve. The valve is a mechanical device and it is subject to malfunction just like any other mechanical device. Finally, the distal catheter end may become obstructed by tissue. It may also migrate out of its cavity due to movement of the surrounding tissue environment (lungs, heart, bowel...).
Example of distal shunt malfunction:
This patient developed progressive swelling under the chest incision of his Ventricular-Pleural shunt. There was an obstruction at the end of the shunt in the chest cavity. CSF percolated around the shunt catheter into the shunt catheter tract and then into the subcutaneous tissues. It presented as a subcutaneous swelling.
What Is Over drainage of a Shunt?
There are many types of shunts with many different settings. It can be quite complicated to determine the optimal setting for a particular shunt in a particular patient. During this process, shunts may drain too much fluid or too little fluid. If they drain too little, the patient suffers with the hydrocephalus symptoms that person had initially to various degrees. If the shunt drains too much CSF, or if the particular brain is not compliant enough to expand and remains compressed, an over drainage process occurs. Extra fluid begins to accumulate between the covering of the brain called the dura and the brain itself. A subdural collection begins to form.
Overdrainage and subdural fluid collections:
As discussed above, if a shunt drains too much fluid, the brain may collapse inward and extra fluid begins to accumulate between the covering of the brain (the dura) and the brain itself. These subdural collections may be Cerebral Spinal Fluid (CSF) or blood resulting in a subdural hematoma.
Shunts can become infected at the time of surgery or from an infection in another part of the body with the infectious agent being delivered to the shunt via the body fluids such as the blood stream. Infections can be very serious and can lead to strokes, paralysis, or even death. If In the abdomen, one gets peritonitis. If the brain end becomes infected, an infection of the brain can lead to meningitis.
If the distal end of the shunt ends in the pleural cavity (lung cavity) and the patient develops pneumonia, the shunt can become infected. The reverse is true too; should the shunt become infected, the patient could develop a lung infection from the shunt.
If the distal end of the shunt ends in the heart and the shunt becomes infected, the patient may develop endocarditis.
If the distal end of the shunt ends in the abdomen and the shunt becomes infected, the patient may develop peritonitis.
This brain shows areas of purulent infection (pus). The normally clear arachnoid covering of the brain (seen along the edges) is cloudy from the infection. There are tiny areas of hemorrhage (petechial hemorrhages) as well as inflammation. The membranes covering the brain are called meninges. An infection of the meninges is called meningitis.