Predicting gallstone pancreatitis in HIV infected patients

Human immunodeficiency virus (HIV) infection, low cluster of differentiation (CD)4 counts and antiretroviral therapy can cause cholestasis and raised transaminases. In acute pancreatitis, this may render biochemical predictors of a gallstone aetiology inaccurate.

In a prospective observational study, acute pancreatitis was diagnosed by standard criteria. Cholecystolithiasis and bile duct diameter were diagnosed by ultrasound. Cholestasis was defined as two of the following: bilirubin ≥ 21 umol/l, γ glutamyl transferase ≥ 78 U/l, alkaline phosphatase ≥ 121 U/l. Cholangitis was defined as cholestasis and any two sepsis criteria: (temperature > 38˚C, WCC > 12.6 ×10⁹/L, pulse > 90 beats/min). Cholangitis, cholestasis, and bile duct diameter greater that 1 cm were indications for endoscopic retrograde cholangiopancreatography (ERCP). These parameters' ability to predict gallstone pancreatitis (GSP) and choledocholithiasis were compared in HIV+ve and HIV-ve patients.

Sixty-two (26%) of 216 patients had GSP. Twenty four were HIV+ve patients. More HIV+ve patients had cholestasis (p = 0.059) and ERCP (p = 0.004). In HIV+ve patients alanine aminotransferase (ALT) > 100 U/L, gamma glutamyl transferase (GGT) > 2 upper limit of normal and cholestasis had a negative predictive value of 92%, 96.7% and 95.2% respectively. In HIV-ve patients, negative predictive value (NPV) was 84%, 83.8% and 84.6% respectively. Bile duct stones were demonstrated at ERCP in 6 (25%) and 3 (8%) of HIV+ve and HIV-ve patients respectively (p = 0.077). Five of 14 ERCP patients had no bile duct stones. HIV+ve and HIV-ve groups had two deaths each.

Absence at presentation of the abnormal parameters analysed were good predictors of a non-gallstone aetiology particularly in HIV+ve patients. Prior, magnetic resonance cholangiopancreatography (MRCP) or endoscopic ultrasound (EUS) would reduce the number of non-therapeutic ERCPs.