Recurrent hemorrhage after western diamondback rattlesnake envenomation treated with crotalidae polyvalent immune fab (ovine).
BACKGROUND
Recurrent coagulopathy has been observed in patients after rattlesnake envenomation treated with Crotalidae Polyvalent Immune Fab (ovine) [FabAV]. While recurrent coagulopathy is well documented in the literature, clinically significant sequelae have not been reported. We present a case of recurrent thrombocytopenia after western diamondback envenomation treated with FabAV, resulting in an extensive recurrent local hemorrhage.


METHODS
A 24-year-old male presented to our emergency department several hours after western diamondback envenomation. He sustained bites to both hands and the right flank by leaning over his pet "snake enclosure." On presentation, the patient was hypotensive, tachycardic, and thrombocytopenic with a platelet count of 17/nl. Antivenom therapy was initiated according to the standard FabAV protocol. However, sixteen hours after completion of the recommended FabAV infusion, the patient experienced a recurrent thrombocytopenia with a dramatic seventeen point drop in hematocrit. The source of bleeding was clinically attributed to an expanding hematoma at the site of envenomation.


CONCLUSIONS
FabAV has become the standard treatment for symptomatic crotalid envenomation. However, the pharmacokinetics of this drug predispose it to recurrent coagulopathies. While studies have shown persistent and recurrent coagulopathic derangements after FabAV therapy, no clinically significant sequelae have been reported. This report highlights the potential for recurrent local hemorrhagic complications following rattlesnake envenomation, even after treatment guided by the current FabAV protocol.


CONCLUSIONS
Recurrent coagulopathy following FabAV therapy can result in clinically significant hemorrhage, supporting the observation that extended repeat dosing may be necessary to adequately treat subjects of rattlesnake envenomation.
Fazelat
Joyia
J
Albert Einstein College of Medicine, Bronx, New York 10461, USA.
Teperman
Sheldon H
SH
Touger
Michael
M
D000328:Adult; D000818:Animals; D000997:Antivenins / Q000008:administration & dosage / Q000627:therapeutic use*; D003435:Crotalid Venoms / Q000037:antagonists & inhibitors*; D017839:Crotalus; D004334:Drug Administration Schedule; D006400:Hematocrit; D006406:Hematoma / Q000209:etiology; D006470:Hemorrhage / Q000209:etiology*; D006801:Humans; D007140:Immunoglobulin Fab Fragments; D007128:Immunoglobulin Fragments / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D012008:Recurrence; D012909:Snake Bites / Q000628:therapy*; D013921:Thrombocytopenia / Q000209:etiology
D000997:Antivenins; D003435:Crotalid Venoms; C431183:Crotalidae Polyvalent immune Fab; D007140:Immunoglobulin Fab Fragments; D007128:Immunoglobulin Fragments