Late shunt infection: incidence, pathogenesis, and therapeutic implications.

Shunt infections (SI) are a major concern in pediatric neurosurgery. Although SI occurs generally shortly after surgery, it can be very delayed in a number of cases. The incidence of late shunt infection (LSI) is not established, and the sources of contamination are poorly understood. We reviewed 1793 pediatric cases from our database, with a mean follow-up of 9.12 years. We selected 40 cases of SI occurring more than one year after the previous shunt operation. These represented 12.7% of SI, and the annual incidence of LSI was 0.28% in our series. Peritonitis, generally due to appendicitis, was the cause of LSI in 11 cases. Hematogenous contamination was diagnosed in eight cases, because the germ was Haemophilus, Pneumococcus, or Listeria, or an ENT infection had preceded SI; the incidence of purulent meningitis was significantly higher in shunted patients than in the general population. LSI was due in seven cases to bowel. perforation, and in four to direct inoculation, after abdominal surgery or traumatic exposure of the shunt. In the remaining 10 cases, no potential cause of infection was identified, and persistence of a germ since the previous shunt operation was suspected. SI represents a life-long threat after shunting, and may be unrelated to shunt surgery.