Occam's razor in the management of ventriculoperitoneal shunt dysfunction: Diagnosis and management of an unusual pediatric case.

Ventriculoperitoneal (VP) shunt surgery is probably the commonest surgical procedure in neurosurgery. Belying its technical simplicity is the myriad complications associated with it. Shunt malfunction is a common complication associated with this surgery, second only to shunt related infections, which may be associated with it. Sterile cerebrospinal fluid (CSF) eosinophilia (CE) has been reported with VP shunts, which may or may not be related to the dysfunction. Eosinophilia in the CSF has also been associated with a number of other conditions including parasitic infestations in the brain. This may be unrelated to the shunt surgery. We present a case of a child, operated earlier for hydrocephalus, who presented with sub-acute loss of vision and bilateral oculomotor paresis. CSF from a chamber tap revealed eosinophilia. The commonest presenting symptom of shunt malfunction is raised intracranial pressure. There are no reports in the literature of VP shunt malfunction presenting with bilateral oculomotor paresis and decreased visual acuity. The associated CE complicated the clinical picture, especially since the initial brain radiology was normal. We discuss the clinical differential diagnosis of this very interesting presentation, management dilemmas and outcome in this child. This rare clinical presentation was found to be the result of a shunt malfunction and not due to any rare parasitic infestation of the brain. Occam's razor dictates that the simplest explanation in a given situation is usually the most accurate, as is seen in this case.