Therapeutic Plasma Exchange for Venom-Induced Thrombotic Microangiopathy Following Hump-Nosed Pit Viper (Genus: Hypnale) Bites: A Prospective Observational Study

Introduction—Thrombotic microangiopathy (TMA), which is the triad of acute kidney injury (AKI), microangiopathic hemolytic anemia (MAHA), and thrombocytopenia, is a rare complication of snakebites, and in Sri Lanka, it is commonly seen with hump-nosed pit viper (HNPV) bites.Methods—We conducted a prospective observational study of patients with AKI caused by HNPV bites in Teaching Hospital, Ratnapura, Sri Lanka for 6 y, commencing in June 2015. Some patients with TMA underwent therapeutic plasma exchange (TPE) and some did not. These 2 groups were compared. Statistical analysis was carried out using Minitab 18.1. Data were presented as median (IQR).Results—There were 52 (8%) patients with TMA, of whom 21 (45%) were in the TPE group and 26 (55%) were in the non-TPE group. TPE improved time to platelet correction (4 d IQR, 4–5 d] vs 7 d IQR, 5–9 d]; P=0.009), time to MAHA correction (5 d IQR, 3–4 d] vs 7 d IQR, 6–9 d]; P=0.004), time to prothrombin time (PT)/international normalized ratio (INR) correction (1 d IQR, 1–2 d] vs 3 d IQR, 3–4 d]; P=0.003), and time to 20 min whole blood clotting test (WBCT20) correction (2 d IQR, 1–2 d] vs 3 d 1QR 2–3 d]; P=0.020). Renal recovery was predicted by TPE (P=0.048) and highest creatinine level (P=0.001). There was no association between TPE and dialysis dependency at discharge (P=0.597), length of hospital stay (P=0.220), and the number of dialysis cycles prior to discharge (P=0.540). TPE did not improve the number of blood transfusions (5 packs IQR, 3–8.5 packs] vs 4 packs IQR, 0–9 packs]; P=0.290).Conclusions—TPE is effective for TMA in the early correction of platelet counts, MAHA, PT/INR, and WBCT20 in HNPV bites.