Inflammatory cytokines, C reactive protein, and procalcitonin as early predictors of necrosis infection in acute necrotizing pancreatitis.

BACKGROUND: Infection of necrosis is a major risk factor in patients with acute pancreatitis. Systematic use of broad spectrum antibiotics has been recommended in these patients but may induce serious side effects. To better target patients in whom antibiotic prophylaxis could be beneficial, we evaluated whether early serum profiles of interleukin 6 (IL-6), tumor necrosis factor (TNF-alpha, C reactive protein (CRP) and procalcitonin (PCT) help to discriminate between patients who eventually develop infection of necrosis and those who do not. METHODS: Forty-eight patients with acute pancreatitis and a computed tomography (CT) severity index score of more than 3 were prospectively screened. They were then separated into infected and non-infected groups according to the occurrence of infected pancreatic necrosis. The severity of illness was assessed with Ranson's classification and Simplified Acute Physiologic Score II. Serum levels of IL-6, TNF-alpha, CRP, and PCT were measured during the first 3 days after admission. CT-guided fine needle aspiration of pancreatic necrosis was performed to prove infection when sepsis of abdominal origin was suspected. Using the methodology of receiver operating curves, we determined the presence of a threshold for markers that would be predictive of the development of infected necrosis. RESULTS: PCT and IL-6 were higher in the serum of patients who eventually developed infection of necrosis (P < 0.003 and < 0.04, respectively). No difference was noted between the 2 groups for TNF- alpha and CRP. The combination of IL-6 < 400 pg/l and PCT < 2 ng/L best identified patients who were not at risk for necrosis infection. The negative predictive value for these thresholds was 91%, whereas sensitivity and specificity were 75% and 84%. CONCLUSIONS: PCT and IL-6 serum levels were elevated very early in patients who eventually developed necrosis infection. A combination of PCT and IL-6 thresholds could be helpful in identifying a subgroup of patients in whom antibiotic prophylaxis is likely to be ineffective.