Thrombotic microangiopathy in hematotoxic snakebites and its impact on the prognosis: an entity often overlooked

Snakebite associated thrombotic microangiopathy (TMA) is a spectrum of disorders characterized by microangiopathic hemolytic anemia, thrombocytopenia and acute kidney injury (AKI). We carried out this study to find out the prevalence of TMA in hematotoxic snake envenomation and to analyze its impact on the clinical outcome of patients. Retrospective data were collected from the medical records, hospital and lab information system after institutional ethics committee approval. Hematotoxic snake bite patients were categorized into Group 1 (with TMA) and Group 2 (without TMA). Chi square test, Mann-Whitney 'U' test and Odd's ratio (OR) were used for statistical analysis. Out of 331 snakebite cases admitted, 202 (64.33%) were hematotoxic envenomation with a mean age of 42.26 ± 15.61. Majority were males with a male to female ratio of 2.01:1. Lower limb was the most common site of bite (59.9%). The prevalence of coagulopathy, TMA and AKI observed was 56.4, 18.8 and 37.6% respectively. AKI had a significant risk of undergoing hemodialysis when it was associated with TMA (r = 0.635, OR = 19.3182, P < 0.0001). Higher number of patients in Group 1 received more blood products (r = 0.406, OR = 8.525, P < 0.0001). Prolonged hospital stay (17.25 ± 12.23 vs. 8.86 ± 7.18 days, P < 0.0001) and higher complication rates were (33.33% vs. 11.4%, P < 0.0048) observed in patients with TMA. Snakebite associated TMA has a significant impact on the prognosis and understanding the pathophysiology of this entity will help to formulate guidelines.