Chapter 148: Ventricular Shunt Evaluation and Aspiration

INTRODUCTION

Pediatric and adult patients with ventricular shunts frequently seek medical attention in the Emergency Department (ED) with complaints that may or may not be caused by a malfunction and/or infection of these indwelling devices.^1-3 Patients with shunts may present with clinical entities as benign as a viral upper respiratory infection or with a life-threatening condition such as hydrocephalus. The wide range of possibilities is a challenge to the Emergency Physician’s (EP’s) diligence and clinical acumen. The challenge for the EP 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 complications and includes tapping the shunt reservoir in the appropriate circumstance.

Ventricular shunts are lifesaving devices that are particularly prone to complications.⁴ Complications of shunts typically occur soon after placement or revision.^1,5,6 Approximately 30% of patients who undergo a shunt revision present to the ED shortly after discharge. Children who had shunts placed as infants will require two shunt revisions secondary to obstruction within their first 10 years.⁷ The overall shunt infection rate is 10% to 20%.^7-9 Approximately 90% of these infections will present within 3 months of the shunt placement.⁷ Routine injection of the reservoir when placing it may decrease the infection rates.¹⁰ The mortality of shunt-related complications has been estimated to be 4.6%.¹¹ This rate is highly dependent on the type of complication as well as the patient’s initial neurologic examination. There is an enormous financial cost associated with ventricular shunts and their complications.¹¹ The use of best practice guidelines may decrease infection rates.¹² All of the above statistics apply to the population with hydrocephalus treated using indwelling ventricular shunt devices. Many of the complications discussed in this chapter may be greatly reduced in the future with the development of neuroendoscopic techniques.¹³ Patients will continue to present frequently to the ED with a variety of problems related to their ventricular shunts. Unless stated otherwise, the reader should assume that reference is being made to the more common ventriculoperitoneal (V-P) shunt device.

Undershunting is the most common complication and can result from obstruction, malfunction, or breakage of the device.¹⁴ The next most common category of shunt complication is infection despite being impregnated with an antimicrobial coating. Overshunting is the next most common complication. It may be associated with overshunting syndrome which may be associated with a subdural hematoma, hygroma, and slit ventricle syndrome.

Seizures tend to occur at a high rate after shunt placement. There is controversy as to whether shunt placement is the cause of the seizure or whether seizure activity is actually related to other associated conditions.¹⁵ Patients may have problems related to the distal catheter (e.g., peritoneal hernia for abdominal shunts or endocarditis for atrial shunts).¹⁶ There are other ...