Renal complications of infected ventriculoatrial shunts

Contamination of a ventriculoatrial shunt (VAS) with skin organisms that are usually nonpathogenic may be followed by an immunologically mediated renal injury. The bacteria characteristically involved are coagulase-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 the 24 patients with highly elevated CIC and in 1 of the 19 patients with moderately elevated CIC, but none of the 95 patients with normal CIC had evidence of shunt infection. Of the 21 patients with shunt infections, 8 had renal involvement (4 requiring dialysis, and 4 with proteinuria, hematuria, and/or elevated creatinine). Results from kidney biopsy specimens available from 4 patients confirmed glomerulonephritis. Of the 4 patients requiring dialysis at diagnosis, renal function recovered sufficiently to stop dialysis after successful VAS exchange in all but 1. In the other 4 patients, renal symptoms (proteinuria, creatinine) also improved after VAS revision. Chronic infection with S. epidermidis or other bacteria is a continuing problem in patients with VASs and can lead to an immune-mediated renal injury. However, the prognosis for reversal of the renal injury is relatively good if the VAS infection is treated promptly.