title: Successful treatment of crotalid-induced neurotoxicity with a new polyspecific crotalid Fab antivenom.
abstract: OBJECTIVE
  To report the effectiveness of a new polyvalent crotalid antivenom on neurotoxicity associated with North American rattlesnake envenomation. Two syndromes of crotalid-induced neurotoxicity have been reported. In severe envenomation by Crotalus scutulatus scutulatus (Mojave rattlesnake), weakness and fasciculations of various muscle groups, including those innervated by cranial nerves, may develop. Occasionally respiratory insufficiency develops. The second neurotoxic effects is myokymia, a type of fasciculation most frequently reported after bites by Crotalus horridus horridus (timber rattlesnake) and Crotalus atrox (Western diamondback rattlesnake). Conventional polyvalent antivenom is often ineffective in the treatment of venom-induced neurotoxicity.
  
  
  METHODS
  We report a case series of three patients envenomated by North American rattlesnakes, one of which was identified as C scutulatus scutulatus. All three patients experienced neurotoxicity with weakness, paresthesias, and dramatic fasciculations, along with other signs and symptoms of crotalid venom poisoning.
  
  
  RESULTS
  The administration of new polyspecific crotalid antivenom made of ovine Fab was successful in immediately and completely reversing neurotoxicity in each of these patients.
  
  
  CONCLUSIONS
  We report the use of a new antivenom for North American crotalid envenomation that seems to have efficacy in reversing neurotoxicity associated with these bites.
authors.affiliation: San Diego Regional Poison Center, Division of Medical Toxicology, University of California, USA.
authors.forename: R F
authors.initials: RF
authors.lastname: Clark
authors.forename: S R
authors.initials: SR
authors.lastname: Williams
authors.forename: S P
authors.initials: SP
authors.lastname: Nordt
authors.forename: L V
authors.initials: LV
authors.lastname: Boyer-Hassen
mesh_terms: D000328:Adult; D000818:Animals; D000997:Antivenins; D003435:Crotalid Venoms / Q000037:antagonists & inhibitors* / Q000276:immunology; D005260:Female; D006801:Humans; D007140:Immunoglobulin Fab Fragments; D008297:Male; D008875:Middle Aged; D009422:Nervous System Diseases / Q000209:etiology*; D012756:Sheep; D012909:Snake Bites / Q000150:complications / Q000628:therapy*; D017819:Viperidae
chemical_list: D000997:Antivenins; D003435:Crotalid Venoms; D007140:Immunoglobulin Fab Fragments