Novel radiological technique to recognize acute liver failure caused by yellow phosphorous containing rodenticides

Yellow phosphorous rodenticide (YPR) poisoning is the commonest cause for acute liver failure (ALF) in southern and western India. Due to medicolegal issues, history of YPR ingestion may not be available. As early recognition of YPR poisoning is important and there are no specific biochemical assays, other early predictors to identify this entity is necessary. We evaluated the diagnostic role of plain computed tomography (CT) in identifying YPR-induced ALF. All patients admitted to the liver unit with a diagnosis of ALF underwent a plain CT scan abdomen. Demographic details, clinical history, laboratory parameters, liver attenuation index (LAI) calculated on CT scan, treatment details, need for liver transplantation and clinical outcome were analyzed. Parameters for YPR-induced ALF (ALF-YPR) and other causes (ALF-OTH) were compared. Ability of LAI to distinguish ALF-YPR and ALF-OTH was analyzed using receiver operating characteristic (ROC) curve analysis. Twenty-four patients (15 female [62.5%]) were included in the study. Thirteen patients (54%) had YPR poisoning, while the rest formed the ALF-OTH group (11,46%). ALF-YPR patients had higher transaminase levels, lower peak serum bilirubin levels. ALF-YPR livers had significantly lower LAI as compared to ALF-OTH (- 30 vs. - 8, p = 0.001). On ROC curve analysis, an LAI greater than - 18 ruled out YPR as the cause for ALF with 91% sensitivity and 85% specificity. On regression analysis, LAI was the only independent factor predicting ALF-YPR (odds ratio - 0.86, [0.76, 0.96] p = 0.008). Our data shows that LAI on plain abdominal CT scan can be used to quickly recognize ALF-YPR in unclear cases so that necessary treatment protocol can be activated, or patient transfer arranged. Our analysis shows that an LAI greater than - 18 can reliably rule out YPR ingestion as the cause for ALF.