Cerebrospinal fluid (CSF) shunts are critical for many patients surviving congenital central nervous system anomalies, infection, or intracranial hemorrhage. Infection is a common complication of these devices and a leading cause of morbidity and hospitalization. Despite this, there is little consensus on the optimal means to prevent and treat these infections.

PATHOGENESIS

Most CSF shunts are silastic tubes inserted into the cerebral ventricles or subarachnoid space and connected to a pressure-regulating valve on the external skull. The proximal shunt is connected to tubing tunneled under the skin to the peritoneal cavity (ventriculoperitoneal shunt). In situations where intraperitoneal drainage is not feasible, the shunt may drain into the right atrium (ventriculoatrial shunt) or pleural cavity (ventriculopleural shunt).

The reported incidence of CSF shunt infections ranges from 1% to 30%, with an average of ≈10% in recent studies. Risk factors for infection include previous surgical revision, a short interval from the time of placement or revision, younger age (particularly premature neonates), a less-experienced surgeon, previous infection, endoscopic surgery, and the presence of a postoperative CSF leak. Shunt valve design does not appear to influence infection rates.

The majority (40% to 75%) of CSF shunt infections are caused by coagulase-negative Staphylococcus spp. Staphylococcus aureus and gram-negative bacilli are each responsible for between 6% and 35% of infections. Escherichia coli, Klebsiella spp., and Pseudomonas aeruginosa are the most commonly reported gram-negative pathogens. Anaerobic bacteria, especially Propionibacterium spp., and fungi are occasionally reported.