Recurrent and Persistent Coagulopathy Following Pit Viper Envenomation

Abstract

Prolonged or recurrent coagulopathy may occur after envenomation by North American pit vipers. Patients treated with Fab-based antivenom may benefit from periodic rather than single-bolus dosing. Patients with coagulopathy should undergo close monitoring during the first 2 weeks after snakebite.

Recurrent hemorrhage after western diamondback rattlesnake envenomation treated with crotalidae polyvalent immune fab (ovine)

“…In conclusion, this case supports the observation that extended repeat dosing of FabAV may be necessary to adequately treat subjects of rattlesnake envenomation (2,5,7,9,12,13). Based on clinical data from Dart et al, the manufacturer currently recommends administering 4-6 vials FabAV over one hour (repeated if control of envenomation is not achieved after the first dose) followed by 2 vials every 6 hours for a total of 18 hours (2,4).…”

“…Beyond this period of treatment, the management of North American crotalid envenomation is not well defined. Recurrent coagulopathy may be found as late as two weeks after envenomation, particularly in those individuals with initial coagulopathic derangements (5,11). While the clinical significance of this phenomenon has not been well studied, this case highlights the potential for dangerous delayed hemorrhagic complications following FabAV therapy.…”

“…He developed extensive additional bleeding into the muscles of the right flank, with a further drop in hematocrit. As prior studies have reported stabilization of local injury after FabAV therapy (5,9), it is of particular interest that the patient's clinical course included extensive recurrent hemorrhage at the site of initial envenomation.…”

“…It is formulated using venoms from the following species: Crotalus atrox (Western diamondback rattlesnake), C. adamanteus (Eastern diamondback rattlesnake), C. scutulatus (Mojave rattlesnake), and Agkistrodon piscivorus (cottonmouth or water moccasin) (4). Recurrence of coagulapathy, including hypofibrinogenemia, thrombocytopenia and increased prothrombin time, has been documented with the use of FabAV (5). Both the management and clinical significance of recurrent coagulopathy are not well defined in the literature.…”

Prolonged Coagulopathy Following Rattlesnake Envenomation Responsive to Antivenom: A Case Report

“…The recurrence phenomenon and unique clinical aspects of this case may have also contributed to the protracted course. Recurrence of coagulopathy following antivenom therapy occurs in 45% to 53% of patients up to 14 days after crotalid envenomation [9,10]. Mechanisms to explain the phenomenon include (1) Pharmacokinetthe physical exam findings included blood oozing from the urethral meatus around the foley catheter and from four puncture wounds on his forearm.…”