The role of ethylene oxide allergy in sterile shunt malfunctions

Failure of an intact ventriculoperitoneal shunt, in the absence of an overt infection, is often due to its occlusion by cellular debris and/or an abdominal pseudocyst. This failure is thought to be caused by an infection by an organism which is difficult to culture or by some poorly defined allergic response to the shunt materials. Little attention has been directed to the treatment that the shunts receive prior to implantation: specifically, their exposure to ethylene oxide as a means of sterilization. We have found ethylene oxide metabolites in the spinal fluid of children with shunt malfunction months after their systems were implanted. Many of these patients had coincident CSF eosinophilia. In addition, two of the children had detectable serum IgE antibody directed against an albumin-ethylene oxide conjugated protein. Both of these children had several shunt malfunctions within a short period, yet neither child could be shown to have a shunt infection despite multiple cultures. We therefore suggest that in some patients proteins altered by ethylene oxide incite an IgE mediated response which may lead to shunt malfunction.