A Trend of Platelet Indices in Patients with Green Pit Viper Toxin

Abstract

The green pit viper (Trimeresurus albolabris and Trimeresurus macrops) is a common venomous snake in Thailand. The green pit viper venom has major effects on the hematologic system. The venom is found to have a thrombin-like effect in vitro but cause a defibrination syndrome in vivo. Unlike other pit viper snakes (such as Malayan pit viper and Russel's pit viper), the venomous effect on red blood cells is rarely mentioned. Clinical features of venomous snake bites vary from asymptomatic to fatal bleeding. In this study, an attempt was made to discern hematologic parameters in green pit viper envenomation and to characterize the changes in blood cells. The study included data from 40 patients who were hospitalized at the King Chulalongkorn Memorial Hospital during 1995 to 1999 and 40 normal, healthy subjects as control. Concerning platelet determination, significantly decreased (p < 0.05) total platelet count and mean platelet volume (MPV) were demonstrated in envenomous blood. The changes in blood cells may be partly due to the effect of green pit viper toxin on the platelet morphology. However, the explanation of this phenomenon requires further investigation for the specific pathophysiology. The components of green pit viper venom that have these hematologic effects in humans are interesting and should be further identified.

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

“…25 It was shown in both in vivo and in vitro tests that the venom of the white-lipped green pit viper ( Trimeresurus albolabris ) in Thailand has a direct effect on platelets by decreasing mean platelet volume and the number. 26,27 The venom of this snake also has major effects on red blood cells by decreasing mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration. 28 In hump-nosed pit viper bites Rathnayaka et al also observed reduction of mean corpuscular volume in 11.7%, decreased mean corpuscular hemoglobin in 18.4%, reduced mean corpuscular hemoglobin concentration in 9%, and reduction of mean platelet volume in 6.5% of envenomed patients.…”

The Usefulness of Platelet Distribution Width and Platelet Distribution Width to Lymphocyte Ratio in Predicting Severity and Outcomes in Patients with Snakebite

“…26 Another study demonstrated that platelet count and MPV were significantly lower in envenomated blood samples compared to the healthy group. 27 To the best of our knowledge, there have been no previous studies evaluating PDW and PDWLR in snakebite envenomation.…”

Retrospective Documentation of a Confirmed White-Lipped Green Pit Viper (Trimeresurus albolabris Gray, 1842) Bite in the South-Central Hills of Nepal

“…Despite the risk of systemic bleeding, this patient did not undergo sufficient investigations to assess the possible evolution of systemic coagulopathy. Although thrombocytopenia is a common hematological effect and a hallmark of hematological disorders due to pit viper envenomation, 23,36 –38 platelets were only measured in a single assay that detected mild thrombocytopenia (Table 1). For the proper diagnosis of pit viper bite, platelets should be measured on arrival and serially monitored including for a week or more postdischarge.…”