Ventriculo-Peritoneal shunt / Ventriculo-Atrial (RA) Shunt

VPS Infection
• average incidence 10%, highest rates in young
• #1 cause: intraop surgical wound contamination (skin): >50% coag neg staph, >20% staph aureus, 15% gram neg bacilli

Causes of infection:
(1) colonization of shunt -> shunt malfunction -> lethargy, headache, vomiting, full fontanelle, low grade fever. Occurs within months of surgery. CSF is sterile. The organism is seen in the shunt reservoir only.
(2) wound infection, usually staph aureus -> infection, dehiscence along shunt tract within days/weeks. Causes fever and shunt malfunction.
(3) distal infection with peritonitis: abdominal sx, no shunt malfn, usually secondary to bowel perf because of shunt placement or translocation of bacteria across bowel wall. Organisms are isolated from distal portions of the shunt
(4) infection associated with meningitis: Strep pneumo, N. meningitidis, H. flu.

Treatment
• For colonization and distal infection with peritonitis. Treat the specific organism.
• #1 = parenteral anti-staph penicillin + intrashunt vancomycin; if resistant, use systemic and intrashunt vancomycin
• for gram negative bacilli, use a 3rd generation cephalosporin and intrashunt aminoglycoside
• for the intrashunt vanco or aminoglycoside monitor levels to avoid toxicity
• remove shunt in most cases

Best treatment
• systemic/intrashunt abx, the exteriorize distal end
• replace shunt on other side
• there is a higher relapse for: abx only or abx+partial shunt revision
• if wound infection: shunt must be removed, place temporary cath to drain, new shunt on other side

Prevention of infection
• surgical sterility
• perioperative use of abx in surgery