Peri-mortem rigidity in a fatal case of severe salicylate poisoning

Abstract

Introduction

There has been a previous case report of peri-arrest muscle rigidity in the setting of severe salicylate poisoning (serum salicylate concentration 1,500 mg/L), described as paratonia or rapid rigor mortis. We present an image of rapid rigor mortis in another fatal salicylate poisoning.

Case summary

We report a 42-year-old male with severe salicylate poisoning (peak salicylate concentration 1,600 mg/L). During the peri-arrest period, the patient developed isotonic flexion of the upper and lower extremities, the clinical signs of rapid-occurring rigor mortis. Despite resuscitative efforts, the patient died.

Image

Our patient is exhibiting peri-arrest rigidity in the upper extremities.

Discussion

Peri-mortem rigidity is due to depletion of adenosine triphosphate. Severe salicylate poisoning causes uncoupling of oxidative phosphorylation which prevents the production of adenosine triphosphate, which is required to release myosin from actin to allow the muscle to relax. A limitation of our report is that we did not definitively exclude other uncouplers of oxidative phosphorylation, such as 2,4-dinitrophenol. However, the history of aspirin ingestion was provided by the patient and corroborated by his mother, and it was confirmed by measurement of his salicylate concentration.

Conclusion

We hypothesize that in our patient, rapid-occurring rigor mortis likely resulted from depletion of adenosine triphosphate. This occurred as a result of uncoupling of oxidative phosphorylation in the mitochondria from severe salicylate poisoning, as adenosine triphosphate is required for muscle relaxation.

Keywords:

• Oxidative phosphorylation
• paratonia
• rapid rigor mortis
• salicylates
• uncoupling

Acknowledgement

An abstract of these data was presented at the North American Congress of Clinical Toxicology annual meeting held in Montreal, QC, Canada in 2023.

Ethical aspects

Attempts were made to contact the patient’s next of kin, but unfortunately, we were unable to make contact.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors reported there is no funding associated with the work featured in this article.