Clinical manifestations and management of scorpion envenomation

The most venomous scorpion species are Buthotus tamulus of India, the Leiurus quinquestriatus and Androctonus crassicauda of North Africa and the Middle East, the Tityus serrulatus of Brazil, and the Centruroides suffussus of Mexico. The severity of scorpion envenomation varies with the scorpion's species, age, and size, and is much greater in children. Systemic intoxication reflects the overstimulation of the CNS, the sympathetic and parasympathetic nervous system. Severity ranges from local pain and paresthesia to fatal cardiotoxicity and encephalopathy. Symptoms include: agitation, tachycardia, vomiting, abdominal pain, salivation, diaphoresis, dehydration, muscle rigidity and twitching, tremor, seizures, coma, pupillary changes, hyperthermia, tachyarrythmias and occasionally bradyarrhythmias, hypertension, and less often hypotension, cardiac failure, and priapism in males. Laboratory abnormalities include: hyperglycemia, leucocytosis, transient elevation of cardiac and pancreatic enzymes, ischemic changes in the ECG, and evidence of cardiac dysfunction on echocardiography. The principles of management are: observation, cardiac monitoring, supportive treatment with intravenous fluids and electrolytes, and a meticulous use of cardiovascular agents: vasodilators, adrenergic antagonists, or calcium channel blockers in the hypertensive phase; and inotropic agents in the event of hypotension. Antiarrhythmics such as lidocaine, may be required. There is increasing evidence for the efficacy of specific antivenom. The advance in supportive care and antivenom efficacy has markedly improved the outcome of patients with scorpion envenomation.