RENAL COMPLICATIONS OF INFECTED VENTRICULOATRIAL SHUNTS

Contamination of a ventriculoatrial shunt (VAS) with skin organisms th at are usually nonpathogenic may be followed by an immunologically med iated renal injury. The bacteria characteristically involved are coagu lase-negative Staphylococci (e.g., Staphylococcus epidermidis), which strongly adhere to the plastic surface of the VAS. These bacteria are protected from the body's natural defense mechanisms and respond only poorly to antibiotics. As a result, their growth persists and produces a continuous antigenic stimulation. Circulating immune complexes (CIC ) are an appropriate tool to screen for chronically infected VASs. We followed CIC in 138 VAS patients. An infected VAS was seen in 20 of th e 24 patients with highly elevated CIC and in 1 of the 19 patients wit h moderately elevated CIC, but none of the 95 patients with normal CIC had evidence of shunt infection. Of the 21 patients with shunt infect ions, 8 had renal involvement (4 requiring dialysis, and 4 with protei nuria, hematuria, and/or elevated creatinine). Results from kidney bio psy specimens available from 4 patients confirmed glomerulonephritis. Of the 4 patients requiring dialysis at diagnosis, renal function reco vered sufficiently to stop dialysis after successful VAS exchange in a ll but 1. In the other 4 patients, renal symptoms (proteinuria, creati nine) also improved after VAS revision. Chronic infection with S. epid ermidis or other bacteria is a continuing problem in patients with VAS s and can lead to an immune-mediated renal injury. However, the progno sis for reversal of the renal injury is relatively good if the VAS inf ection is treated promptly.