Severe scorpion envenomation — DTM&H MCQ

Correct answer: D — Acute pulmonary oedema and cardiovascular collapse

The correct answer is D, acute pulmonary oedema and cardiovascular collapse. Severe scorpion envenomation, classically from buthid species found across South and Southeast Asia including Cambodia, triggers a massive autonomic storm with catecholamine release that produces myocarditis, left ventricular dysfunction, and non-cardiogenic capillary leak, culminating in acute pulmonary oedema and cardiovascular collapse within hours to a few days of the sting. Children are disproportionately affected because of a higher venom-to-body-mass ratio, and this cardiorespiratory phase, not the neurotoxic paralysis itself, is the dominant cause of death. The ascending paralysis and respiratory difficulty in this child signal progression toward this cardiopulmonary crisis, which requires urgent recognition, oxygen, afterload reduction, and antivenom where available. Why the other options are wrong: B. Anaphylactic shock: this is an IgE-mediated hypersensitivity reaction to venom antigens in a sensitised individual, not the primary toxin-mediated pathology of severe envenomation, and it is not the characteristic life-threatening complication described here. A. Disseminated intravascular coagulation: DIC is a recognised feature of some viper (snake) envenomations with haemotoxic venom, not the typical presentation of scorpion sting, which is predominantly neuro- and cardiotoxic. C. Rhabdomyolysis with renal failure: this is more characteristic of severe crush injury, some snake envenomations, or extreme neuromuscular hyperactivity, and is not the principal driver of mortality in scorpion sting. E. Cerebral haemorrhage: intracranial bleeding is not a recognised direct complication of scorpion venom toxicity and has no mechanistic link to the catecholaminergic cardiotoxicity described. Key point: In severe scorpion envenomation the catecholamine surge causes myocardial dysfunction and capillary leak, so acute pulmonary oedema with cardiovascular collapse, not paralysis itself, is the leading cause of death, especially in children.

Reference: WHO Eastern Mediterranean Regional Office, 'Scorpion sting syndrome: epidemiology, clinical presentation and management of 2240 cases', Eastern Mediterranean Health Journal, 1997, https://www.emro.who.int/emhj-volume-3-1997/volume-3-issue-1/article10.html