What neurotoxic findings have recently been observed in patients envenomated by the Southern Pacific rattlesnake (Crotalus helleri)?
The authors of the cited reference therorize that small basic peptides found in Southern Pacific rattlesnakes in the Los Angesles region posesses excitatory, mytoxic, and beta neurotoxic properties that resulted in dysarthria, dysphagia, myokymia and parasthesias that seemed to respond well to antivenom. A shift in venom composition to include Mojave A toxin was not excluded.
Levine M, Tashman D, Recchio I, Friedman N, Seltzer J, Minns A, LoVecchio F. Neurotoxicity Associated With the Southern Pacific Rattlesnake (Crotalushelleri). Ann Emerg Med. 2023 Mar;81(3):318-322. doi: 10.1016/j.annemergmed.2022.08.020. Epub 2022 Oct 15. PMID: 36253294.