Could rising BUN predict the future development of infected pancreatic necrosis?

Background: Infected (peri)pancreatic necrosis (IPN) in acute pancreatitis (AP) is associated with organ failure (OF) and high mortality. There are no established early markers of primary IPN. This study aimed to assess the association of simple parameters with primary IPN in AP.

Methods: We retrospectively studied 281 patients with AP admitted to Mayo Clinic hospitals and identified those with microbiologically confirmed infections in (peri)pancreatic necrosis and collections. We defined primary IPN as infection of (peri)pancreatic necrotic tissue that developed before interventions. We recorded admission hematocrit, BMI, BUN, serum creatinine, SIRS score and development of persistent organ failure within 48 h of admission; and performed serial SIRS and BUN calculations for at least 48 h. We used univariate and multivariable analysis to assess associations and expressed results as odds ratio (OR)[95% CI].

Results: 27 (9.6%) patients developed IPN, of which 21 (77.7%) had primary IPN. 38.1% had Gram positive, 9.5% Gram negative and 52.3% mixed bacterial infections. Five (23.8%) of the patients with IPN had fungal infection. On univariate analysis, SIRS ≥ 2 at admission, rise in BUN by 5 mg/dL within 48 h of admission, persistence of SIRS for 48 h and development of persistent OF within 48 h of disease had significant association with development of primary IPN with OR (95% CI) of 4.12 (1.53-11.15), 10.25 (3.95-26.61), 1.19 (1.69-10.39) and 7.62 (2.58-21.25) [2-tailed p = 0.004, <0.0001, 0.002 and <0.0001] respectively. On multivariable analysis, only rise in BUN by 5 mg/dL within 48 h of admission was associated with primary IPN (p = 0.007).

Conclusions: Rising BUN within 48 h of admission can be used to predict development of primary IPN in AP.