Hyperamylasaemia and acute pancreatitis in paracetamol poisoning

Abstract

Hyperamylasaemia and even acute pancreatitis have been reported in patients with paracetamol poisoning. To describe the incidence, clinical characteristics, and prognostic implications of hyperamylasaemia in paracetamol poisoning. Six hundred and two patients transferred to a specialized unit with severe paracetamol poisoning and 212 unselected patients admitted from the local region. Retrospective study based on hospital charts. The optimum threshold of serum amylase to discriminate non-survivors was identified. An elevated serum amylase (>100 U/L) occurred in 28 of the unselected patients (13%), in 218 of the transferred patients (36%), and in 118 of 148 patients (80%) with fulminant hepatic failure. Only 33 cases of paracetamol-associated acute pancreatitis were diagnosed. A threshold serum amylase of 150 U/L to discriminate non-survivors had sensitivity 76%, specificity 85%, positive predictive value 33%, and negative predictive value 97%. In a logistic regression analysis, a serum amylase > 150 U/L was associated with an excess mortality (odds ratio 5.0, 2.6-9.7). Hyperamylasaemia is frequent in patients with paracetamol poisoning, whereas clinical acute pancreatitis occurs rarely. The incidence of hyperamylasaemia increases with the degree of hepatic dysfunction. A serum amylase exceeding 1.5 times the upper normal limit indicates a poor prognosis.