Reported are the cases of three hydrocephalic patients who developed a
clinically heterogenous entity with an allergic rejection of their si
licone ventriculoperitoneal shunts. All of the patients had an origina
l presentation indicative of a shunt infection, but laboratory analysi
s revealed sterile cerebrospinal fluid in all three cases. The typical
course included recurrent skin breakdowns over the shunt tract, subse
quent infections and development of fungating granulomas. Treatment, w
ith successful resolution of the symptoms, included changing the shunt
material from silicone to polyurethane, with immunosuppression in one
patient and removal of the shunt altogether in the other two patients
. The roles of the immune system and silicone in the pathophysiology o
f this condition are discussed.