Delayed onset of myotoxicity following red-bellied black snake envenoming: a case report

Myotoxicity is an important and recognized effect of red-bellied black snake envenoming that remains poorly understood but can result in severe illness. Prior observational data have shown that myotoxicity develops less frequently and later than other envenoming effects, including systemic symptoms and anticoagulant coagulopathy, which are likely to coexist in an envenomed victim. Current recommendations for managing snake bite victims in Australia include serial clinical and laboratory assessments for envenoming for at least 12 hours post-bite.

We report the case of an 18-year-old white male individual with red-bellied black snake envenoming who developed delayed-onset myotoxicity. His symptoms included abdominal pain, vomiting, and generalized myalgias. Myotoxicity occurred after the standard 12-hour post-bite observation period, with serum creatine kinase remaining less than 1000 U/L at 17.5 hours post-bite before increasing to a peak of 93,790 U/L at 57 hours post-bite. He developed myalgia and myoglobinuria at 22 hours post-bite without associated renal impairment. He did not receive antivenom. He was treated with intravenous fluids and was discharged on day 4 with declining creatine kinase levels and made a full recovery.

Our case of red-bellied black snake envenoming with delayed-onset myotoxicity was managed successfully without antivenom. Cases of delayed myotoxicity may warrant prolonged observation with supportive care.