Microangiopathic Hemolytic Anemia Following Three Different Species of Hump-Nosed Pit Viper (Genus: Hypnale) Envenoming in Sri Lanka

Abstract

There are 3 species of hump-nosed pit vipers in Sri Lanka: Hypnale hypnale, Hypnale zara, and Hypnale nepa. The latter 2 are endemic to the country. Microangiopathic hemolytic anemia (MAHA) is a known complication of hump-nosed pit viper bites. It was previously documented as a complication of general viper bites and not species specific. We report a series of 3 patients who developed MAHA after being bitten by each species of hump-nosed pit viper. The first patient was bitten by H hypnale and developed a severe form of MAHA associated with acute kidney injury and thrombocytopenia falling into the category of thrombotic microangiopathy. The other 2 developed MAHA that resolved without any complications.

Snakebite associated thrombotic microangiopathy: a systematic review of clinical features, outcomes, and evidence for interventions including plasmapheresis

“…These included 31 single case reports [13,15,16,[22][23][24], 31 case series [8,9,14,17,[25][26][27], nine cohort studies [11,[84][85][86][87][88][89][90][91], and one nested case control study (Table 1) [92]. Eighteen studies contained completely or partially duplicated cases which were merged (S5 Table) [9,11,14,23,26,41,60,[66][67][68]75,76,81,[84][85][86]88,92]. After merging, 351 unique cases fitting the inclusion criteria for TMA were included Table 1).…”

Acute ischemic stroke: a rare complication of hump-nosed pit viper (Hypnale spp.) bite: a case report

“…When red blood cells flow through these blocked vessels, they get distorted, which can be seen on peripheral blood microscopy as schistocytes (fragmented red blood cells). This condition is called microangiopathic hemolysis and can be observed in Hypnale bites [ 6 ]. When this organ ischemia occurs together with thrombocytopenia and microangiopathic hemolysis, the process is called TMA, which can also be observed in hump-nosed pit viper bites [ 7 ].…”

“…It frequently causes local envenoming and less commonly cause systemic effects such as acute kidney injury and venom-induced consumption coagulopathy (VICC) [ 2 , 3 ]. Myocardial infarction (MI) [ 4 ], Kounis syndrome [ 5 ], microangiopathic hemolysis [ 6 ], thrombotic microangiopathy (TMA), hemolytic uremic syndrome (HUS), and thrombotic thrombocytopenic purpura (TTP) [ 2 , 7 ] are some atypical presentations of hump-nosed pit viper bites. Currently, no antivenom is available for Hypnale bites in Sri Lanka or India, and supportive treatments are carried out for these bites.…”

Thrombotic Microangiopathy Following Hypnale zara (Hump-Nosed Pit Viper) Envenoming: The First Known Case Report from Sri Lanka

“…TMA, which is the triad of AKI, MAHA, and thrombocytopenia, is a known complication of hump-nosed viper envenomation 6,8,12 –16 and occurs in 3 to 5% of all Hypnale bites. 6,17 Microangiopathic hemolysis occurs in 7% of patients with Hypnale bites, 6,17 and all 3 species of genus Hypnale cause MAHA, 6,11 which is diagnosed from the presence of more than 3 fragmented red blood cells (schistocytes) in a high-power field on peripheral blood microscopy. Our patient had more than 4 fragmented red blood cells in a high-power field on day 3 of snakebite, reduced hemoglobin level since day 2 of snakebite, and increased lactate dehydrogenase level measured on day 8 of bite, which are all suggestive of intravascular hemolysis.…”

“…Hump-nosed pit viper bites commonly cause local envenomation, such as pain, swelling, necrosis, and blistering. 5 –7 Systemic manifestations such as acute kidney injury (AKI), 7,8 chronic kidney disease, 8 –10 coagulopathy, 5,7 microangiopathic hemolysis, 11 and thrombotic microangiopathy (TMA) 12 –16 may rarely occur after bites. TMA has previously been reported after bites by H hypnale 6,8,12,14,16 but has not been documented in H zara or H nepa bites.…”