Morphologic changes in intercostal muscle tissue associated with a viper (Agkistrodon halys blomhoffi) bite

Area of Science:

• Toxicology
• Neurology
• Pathology

Background:

• Snakebite envenomation by vipers (Agkistrodon halys blomhoffi) can lead to severe systemic complications.
• Acute renal and respiratory failure are known, but long-term muscle pathology is less understood.

Observation:

• A 73-year-old woman developed acute renal and respiratory failure post-viper bite.
• Persistent respiratory failure prompted intercostal muscle biopsy on day 40.
• Histochemical and electron microscopy revealed mixed degeneration and regeneration in muscle fibers.

Findings:

• Muscle biopsy showed varied fiber sizes, with many small fibers identified as type 2C.
• Type 2C fibers indicate a regenerative stage of acute rhabdomyolysis.
• Ultrastructural analysis demonstrated coexisting degenerative and regenerative changes within muscle tissue.

Implications:

• The findings suggest ongoing muscle fiber degeneration alongside regeneration.
• Slow allergic reactions to snake venom may contribute to persistent degenerative muscle changes.
• This highlights the potential for delayed myotoxicity following viper envenomation.