Use of polyvalent equine anti-viper serum to treat delayed coagulopathy due to suspected Sistrurus miliarius streckeri envenomation in two children.
BACKGROUND
Western Pygmy Rattlesnake (WPR) envenomation reportedly causes refractory and persistent coagulopathy when treated with CroFab®(Crotalidae Polyvalent Immune Fab). We report two cases where polyvalent equine anti-viper serum (AntivipmynTRI®) was used to treat recurrent coagulopathy in children.


METHODS
The first patient was a 16-month-old male who was bitten by a confirmed WPR. The patient received a total of 18 vials of CroFab®. His labs normalized, swelling gradually improved, and the child was discharged to home. On day 5, the child returned to the emergency department with a great deal of inguinal tenderness. Labs were obtained and the child's INR was >13.1, while the fibrinogen was <60 mg/dL and the d-dimer was 11.72 mg/L. A decision was made to administer Antivipmyn TRI®, and the child received a total of 10 vials. Lab values significantly improved: INR 1.2, fibrinogen 93 mg/dL, and d-dimer 4.21 mg/L. The second patient was a 20-month-old male who presented following snake envenomation. The child was administered a total of 22 vials of CroFab®over approximately 70 h following envenomation. Physical exam continued to improve, however, lab results showed an increasing INR 1.98, decreasing platelet count 124 × 103per μL, fibrinogen <60 mg/dL, and d-dimer >20 ug/mL. A total of 15 vials of Antivipmyn TRI®were administered to this patient. Following this administration, labs and clinical exam both significantly improved. Labs revealed INR 1.16, fibrinogen 110 mg/dL, d-dimer 3.2 mg/L and platelet count 215 × 103/μL.


CONCLUSIONS
CroFab®is still the first-line treatment for children bitten by a WPR, but in some cases patients develop a recurrent coagulopathy. The rapid response demonstrated by Antivipmyn TRI®leads us to conclude that this is a potential therapy for this clinical situation.
a Oklahoma Center for Poison and Drug Information , Oklahoma City , OK , USA.
Kristie L
KL
Williams
b The Children's Hospital at Saint Francis , Tulsa , OK , USA.|c University of Oklahoma - Tulsa School of Community Medicine , Tulsa , OK , USA.
Megan
M
Woslager
a Oklahoma Center for Poison and Drug Information , Oklahoma City , OK , USA.
Stephanie L
SL
Garland
b The Children's Hospital at Saint Francis , Tulsa , OK , USA.|c University of Oklahoma - Tulsa School of Community Medicine , Tulsa , OK , USA.
Roger P
RP
Barton
a Oklahoma Center for Poison and Drug Information , Oklahoma City , OK , USA.|d Integris Baptist Medical Center , Oklahoma City , OK , USA.
William
W
Banner
D000818:Animals; D000997:Antivenins / Q000627:therapeutic use*; D001778:Blood Coagulation Disorders / Q000188:drug therapy* / Q000209:etiology; D017839:Crotalus; D004487:Edema / Q000188:drug therapy / Q000209:etiology; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism; D005340:Fibrinogen / Q000378:metabolism; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000627:therapeutic use*; D007155:Immunologic Factors / Q000627:therapeutic use*; D007223:Infant; D008297:Male; D010146:Pain / Q000188:drug therapy / Q000209:etiology; D010976:Platelet Count; D012909:Snake Bites / Q000188:drug therapy*; D014757:Viper Venoms / Q000633:toxicity*
D000997:Antivenins; C431183:Crotalidae Polyvalent immune Fab; D005338:Fibrin Fibrinogen Degradation Products; D007140:Immunoglobulin Fab Fragments; D007155:Immunologic Factors; D014757:Viper Venoms; C538992:antivipmyn Africa; C036309:fibrin fragment D; D005340:Fibrinogen
Snake bite; antivipmyn TRI®; western pygmy rattlesnake