Ventriculoperitoneal Shunts

Diagnosis/Definition

• Shunt dependency is a condition of multiple etiology in which the spinal fluid produced in the ventricles of the brain is not absorbed in a normal fashion. This, in turn, causes enlargement of the ventricular system which generally results in intracranial hypertension or increase in head size in children. VP shunts are designed to relieve this abnormality by redirecting flow of the CSF to the peritoneal cavity.
  Initial Diagnosis and Management
• In the pediatric age group, the diagnosis of hydrocephalus is based on head circumference and CT scanning which shows ventriculomegaly with enlarging head, or, in patients with closed sutures, symptomatic ventricular enlargement.
• The initial management of this is placement of a shunt diversion system (generally from the ventricles to the abdominal cavity). Alternatively, the shunt can be placed into the atrium of the heart or the pleural cavity, but these are much less common.
• Once a shunt is in place, yearly follow-up and examination by the PCP is recommended. These patients should also be examined by a neurosurgeon every 2 years primarily to make sure the child is not outgrowing the length of the shunt tubing.

Ongoing Management and Objectives

The primary objective in a patient with a VP shunt is to ensure, on a regular basis, that the shunt continues to function. In general, this is a clinical diagnosis based on the patient’s complaints and shunt dynamics at the time of testing the shunt. In some severely impaired patients, the diagnosis of continued shunt functioning must be correlated with CT scan.

Indications for Specialty Care Referral

All children or adults suspected of having hydrocephalus, particularly if there are symptoms of intracranial hypertension, should have immediate neurosurgical referral. An exception to this is elderly patients with ventriculomegaly with large subarachnoid spaces in which a diagnosis of normal pressure hydrocephalus is entertained. This initial work-up and differential diagnosis is best done by the Neurology Service unless there are symptoms of severe gait ataxia or urinary incontinence.

In patients with VP shunts, specialty referral from primary care is advisable in the following circumstances:

The patient, usually a child, has symptoms of intracranial hypertension such as headache, lethargy, nausea and vomiting without another explanation such as viral syndrome.

Children who have fever without a usual source seen in the pediatric population (such as ear infections, etc.), especially if they have had a shunt procedure in the previous six months. Shunt infection more than six months after the procedure is extremely uncommon.

Seizures should be referred according to the usual epilepsy guidelines. If seizures are isolated to the shunt as cause, then after initial evaluation, referral to Neurosurgery is appropriate.

Referral to specialty care is indicated if a patient has neglected follow-up for over 2 years.

Note: It is prudent to point out that when patients with VP shunts are being evaluated and the provider feels uncertain about a particular case, then a phone consultation is certainly indicated at that time.

Criteria for Return to Primary Care

Generally asymptomatic patients can be followed in a primary care setting as long as the primary care provider is familiar with the basic principles of VP shunting and signs and symptoms of its malfunction.

• This guideline may not be helpful in every instance. The Neurosurgery Service emphasizes the telephone consultation (253-968-3106) as being an efficient and important means of improving provider communication and ultimately patient care.