WHEN SHOULD I CONSULT MY PHYSICIAN?

Even if the risk of complication is low, the patient or his family need to know that certain complications may arise after the operation.

The main complications of shunts are obstruction, infection and overdrainage. These complications require prompt attention by the patient's physician.

Obstruction

The most common complication is obstruction, which can occur at any point of a ventriculo-atrial or ventriculo-peritoneal shunt.

The ventricular catheter can be obstructed by a blood clot, cerebral tissue, or even tumor cells.

The tip of the ventricular catheter can also become embedded in the choroid plexus or ventricular wall, either directly or following collapse of the walls due to overdrainage.

The cardiac catheter can be colonized by thrombus, while the development of clot around the catheter can lead to pulmonary embolism.

The peritoneal catheter can be obstructed by peritoneum or loops of intestine.

Loss of patency of a shunt may also be due to obstruction by fragments of cerebral tissue or biological deposits (protein deposits, etc.).

Obstruction of the shunt leads to loss of control of hydrocephalus, rapidly reflected by recurrence of the symptoms and signs of raised intracranial pressure.

These symptoms and signs vary from one patient another and over time.

In infants and young children, the symptoms may consist of an abnormal increase in the size of the skull, swelling of the fontanelles, dilatation of scalp veins, vomiting, irritability with loss of attention, downward displacement of gaze and sometimes convulsions.

In older children and adults, the raised intracranial pressure due to hydrocephalus is responsible for headaches, vomiting, visual disturbances, diplopia, drowsiness, slowed movements, gait disorders, psychomotor retardation, possibly causing total disability.

Shunt obstruction can also lead to CSF leakage around the catheter and subcutaneous collection.

If obstruction is confirmed, the shunt should be removed.

Infection

Chronic shunt dysfunction can lead to leaking of CSF along the shunt, increasing the risk of infection.

Local or systemic infection is another possible complication of CSF shunt systems. It is generally secondary to colonization of the shunt by cutaneous bacteria. However, as for any foreign body, the shunt can be colonized by any local or systemic infection. This infection may present in the form of erythema, oedema and cutaneous erosion along the course of the shunt.

Prolonged, unexplained fever may also be due to infection of the shunt system.

Septicemia, in a context of deterioration of the general state, may arise from shunt infection.

The shunt system should be removed and specific treatment should be introduced in the case of infection.

Overdrainage

Overdrainage can lead to collapse of the ventricles (slit ventricles) and the development of subdural haematoma.

In children, depression of the fontanelles, overlapping of skull bones, or even acute craniostenosis or the development of communicating hydrocephalus into obstructive hydrocephalus as a result of stenosis of the aqueduct of Sylvius may occur.

In addition to various symptoms such as vomiting, auditory or visual disorders, drowsiness, adults may also present with headaches occurring in the upright position and resolving in the supine position.

Depending on the clinical and CT findings, the neurosurgeon can correct the symptoms and ventricular size by varying the operating pressure of the Sophy® Adjustable Pressure valve. However, immediate drainage of a subdural haematoma may be indicated.

Others

Failure of a shunt system may also be due to disconnection of its various components.

The ventricular catheter can migrate inside a lateral ventricle. The peritoneal catheter can migrate in the peritoneal cavity in response to intestinal peristalsis and an atrial catheter can migrate in the right side of the heart as a result of blood flow.

An abdominal viscus may also be perforated or occluded by the peritoneal catheter.

Bodily growth may progressively lead to expulsion of the catheters from their site of insertion.

These disorders require immediate resitting of the shunt.

Cases of skin necrosis over the implantation site have been reported.

In the case of implantation on the skull, vibrations due to CSF flow may be perceived.

Cases of silicone allergy have been described.

Cases of epilepsy after ventricular shunting procedures has been reported.

Cases of axial rotation of the valve by the patient have been reported, while implanted on the chest. Such rotation induces reverse lecture of the pressures and a risk of catheter obstruction.

The ruby ball can be maintained in off centering position on its seat by protein deposit or cells accumulation. The consequences of such situation can be:

• A lack of flow regulation of the valve inducing a risk of overdrainage.
• An impaired antireflux function.

Rotor blockage by protein deposit or cells accumulation can make adjustment impossible with the magnet.