Catastrophic acute ischemic stroke after Crotalidae polyvalent immune Fab (ovine)-treated rattlesnake envenomation

We report 2 cases of catastrophic ischemic stroke after Crotalidae polyvalent immune Fab (ovine)-treated rattlesnake envenomation, 1 fatal and the other resulting in significant permanent disability. It is possible these serious adverse events may have been related to venom factor(s), an interaction between venom and antivenom, occult patient blood dyscrasia, or to random unrelated events. We present the rationale for each possibility, and submit the experiences to elicit alternate postulation and communication of similar presentations.