Thrombotic microangiopathy and acute kidney injury in hump-nosed viper (Hypnale species) envenoming: a descriptive study in Sri Lanka

Hump-nosed viper (Hypnale species) bites are common in Sri Lanka and a proportion of these bites lead to coagulation abnormalities and acute kidney injury (AKI). We observed thrombotic microangiopathy (TMA) among some of these patients, but its contribution to severity of AKI and other morbidities remains unknown. Thus, we report a case series of TMA following hump-nosed viper bite addressing the complications and renal out comes in Sri Lanka. This was a prospective observational study carried out at the nephrology unit, Kandy in Sri Lanka from October 2010 to October 2011 and included 11 patients with AKI following hump-nosed viper bites. All eleven cases needed renal replacement therapy (RRT) with intermittent haemodialysis for a period of 1-5 weeks. Of them, 7 patients developed TMA with evidence of microangiopathic haemolytic anaemia (MAHA), thrombocytopenia and severe anaemia needing multiple blood transfusions. They needed longer duration of RRT (range 2-5 weeks); 2 patients developed chronic kidney disease and two died during acute stage. Autopsy study found thrombosis of micro-vessels. Thrombotic microangiopathy could be a causative pathology of AKI in hump-nosed viper bite carrying poor outcome.