Severe acute kidney injury following Sri Lankan Hypnale spp. envenoming is associated with thrombotic microangiopathy.

CONTEXT: Acute kidney injury (AKI) is the most serious clinical manifestation of the Sri Lankan hump-nosed pit viper (Hypnale spp.) bites. Thrombotic microangiopathy (TMA) is increasingly recognized in association with AKI in cases of Hypnale spp envenomation. We investigated AKI in a cohort of cases of Hypnale envenomation, its association with TMA and the early diagnostic value of common biomarkers for AKI occurring. MATERIALS AND METHODS: We conducted a prospective observational study of suspected viper bites and included 103 confirmed cases of Hypnale envenomation, based on venom specific enzyme immunoassay of blood. AKI was defined using the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Thrombotic microangiopathy was diagnosed based on thrombocytopenia (platelet count < 150,000 × 103/µL) and microangiopathic haemolytic anaemia (MAHA). We investigated the diagnostic performance of creatinine, platelet count and INR for AKI within 4 h and 8 h post-bite by area under the receiver operator characteristic curve (AUC-ROC). RESULTS: Ten patients developed AKI: seven AKI stage 1 and three AKI stage 3. Ten patients (10%) developed thrombocytopaenia while 11 (11%) had MAHA. All three AKI stage 3 had thrombocytopaenia and MAHA fulfilling the criteria for TMA. Two of them presented with oliguria/anuria and all three required haemodialysis. Serum creatinine within 4 h post-bite was the best predictor of AKI with AUC-ROC of 0.83 (95% CI: 0.67-0.99) and was no better within 8 h of the bite. CONCLUSIONS: We found that AKI is uncommon in Hypnale spp. envenomation, but an important serious complication. Severe AKI was associated with TMA. A creatinine within 4 h post-bite was the best predictor of AKI.

Thrombotic microangiopathy and acute kidney injury following Sri Lankan Daboia russelii and Hypnale species envenoming.

Context: Thrombotic microangiopathy (TMA) resulting in acute kidney injury (AKI) is an important complication of venomous snakebites. We aimed to describe TMA secondary to Russell's viper (Daboia russelli) and hump-nosed viper (Hypnale spp.) bites and assess the effect of different treatments.Materials and methods: We undertook a prospective observational study of patients with AKI secondary to snakebite over a two-year period. Data recorded included: demographic details, clinical and laboratory features, treatment, complications and outcomes, until hospital discharge and at three months post-discharge. TMA was defined as the development of microangiopathic hemolytic anemia and thrombocytopenia along with AKI. Treatment with therapeutic plasma exchange (TPE; also known as plasmapheresis) and/or fresh frozen plasma (FFP) was determined by the treating clinician. Antivenom was given to all patients with evidence of systemic envenoming following Russell's viper bites.Results: Fifty-nine patients were included in the analysis. Thirty-three (56%) were males and median age was 56 years. Forty-five (76%) developed TMA while a further 11 and two developed isolated thrombocytopenia and microangiopathic hemolytic anemia, respectively. Presence of TMA was associated with increased dialysis requirements (5 vs. 3) and longer hospital stay (18 vs. 12 days). Of the patients with TMA, nine received TPE with or without FFP infusions. The use of TPE was not associated with improved outcomes in patients with TMA based on requirement for blood transfusion, recovery of thrombocytopenia, requirement of dialysis and duration of hospital stay. Patients who did not receive TPE had better renal function at three months compared to patients who received this treatment.Conclusion: Presence of TMA in patients with Daboia and Hypnale bites was associated with a more prolonged course of AKI. Patients with TMA who were treated with TPE did not have improved early or late outcomes compared to patients who were not treated with TPE.