Pediatric and adult patients with ventricular shunts frequently seek medical attention in acute care settings with complaints that may or may not be caused by a malfunction and/or infection of these indwelling devices. The challenge for the Emergency Physician is to determine if the shunt system is functioning properly and if it is a direct cause of the patient's acute problem. This chapter will discuss the complications of ventricular shunt malfunction including infection.
Complications in children with ventricular shunts are common whereas those in adults occur less frequently. Approximately 30% to 40% of infants will experience shunt complications during their first year following shunt placement.1,2 Children who had shunts placed as infants will require two shunt revisions secondary to obstruction within their first 10 years.1 The overall shunt infection rate is 10% to 20%.1,3,4 Approximately 90% of these infections will present within 3 months of the shunt placement.1 These statistics apply to the population with conventionally treated hydrocephalus using indwelling ventricular shunt devices. It is significant to note that with the wide application and development of neuroendoscopic techniques, many of the complications discussed in this chapter may be significantly reduced or possibly eliminated.
Complications resulting from ventricular shunts take many forms.5 These include proximal obstruction (most common), distal obstruction, disconnection, wound and cerebrospinal fluid (CSF) infections, seizures, epidural hygromas, subdural hematomas, low (overdrainage) and high pressure (slit ventricle) syndromes, and cranial deformities. There are other unique complications experienced by the smaller number of patients who have ventriculoatrial (V-A) and ventriculopleural shunt systems and these will be discussed separately. Unless stated otherwise, the reader should assume that reference is being made to the more common ventriculoperitoneal (V-P) shunt device.
Patients with shunts may present with clinical entities as benign as a viral upper respiratory infection or with a life threat like hydrocephalus. The wide range of possibilities is a challenge to the Emergency Physician's diligence and clinical acumen. Common presenting symptoms include headache, fever, vomiting, decreased alertness, neck stiffness, visual changes, malaise, abdominal pain, abdominal distension, and surgical site problems.
Hydrocephalus, a condition defined by an excessive quantity of CSF, is the condition most frequently associated with the initial need for a ventricular shunt or a shunt revision if it malfunctions. Most abnormal accumulations of CSF are identified in the ventricles, although it may also occur in the subarachnoid or subdural spaces.
Several types of hydrocephalus are cited in the literature. Communicating hydrocephalus occurs when there is unobstructed flow of CSF between the ventricular system of the brain and the spinal cord. It frequently occurs in patients who have had a hemorrhage or infectious process whereby particulate matter interferes with the normal circulation and absorption of CSF. A congenital problem such as aqueductal stenosis or a mass lesion in the posterior fossa may obstruct the flow of CSF between the brain and ...