ANDROCTONUS CRASSICAUDA (OLIVIER), A DANGEROUS AND UNDULY NEGLECTED SCORPION .1. PHARMACOLOGICAL AND CLINICAL-STUDIES

Androctonus crassicauda venom has an i.v. LD(50) in mice of 0.32 +/- 0 .02 mg/kg, which makes the scorpion among the most toxic species in th e world. Fifty-one non-fatal and one fatal cases of scorpion sting wer e presented. Pain and tenderness were very common following the sting. Generalized erythema occurred in 20-25% of all infants and children b elow the age of 5 years. Severe CNS manifestations including seizures, unconsciousness and marked irritability occurred mainly in infants an d young children, while hypertension occurred in the majority of victi ms below the age of 11 years. Two pregnant victims were treated with a ntivenom with no bad consequences on mothers or foetuses. The fatal ca se described was inadequately treated with antivenom and presented a r are situation of intracranial coagulation in the basal cisterns or low in the cranial subarachnoid space. The victim developed moderate hydr ocephalus of the communicating type with clear ventricular CSF and str ongly xanthocromic fluid from lumbar puncture. The effects of A. crass icauda venom on isolated hearts, atria and anaesthetized rat blood pre ssure appeared to be mediated largely through stimulation of the auton omic nervous system with predominance of sympathetic stimulation and r elease of tissue catecholamines. Electrocardiograms recorded simultane ously with blood pressure changes showed evidence of ectopic foci duri ng the hypertensive phase and ischaemia, inferior wall infarction and different degrees of heart block during the late hypotensive phase. An droctonus crassicauda venom was unique in following a three-compartmen t open model comprising a central compartment 'blood', a rapidly equil ibrating 'shallow' tissue compartment and a slowly equilibrating 'deep ' tissue compartment. The overall elimination half-life, t(1/2)beta, w as 24 hr, indicating that the venom has the slowest elimination among all known scorpion venoms. The long stay of the venom in the body migh t explain the increased risk of toxicity and the good potential for tr eatment with serotherapy even hours after the sting.