Signs and symptoms show either cholinergic or adrenergic predominance. Cholinergic symptoms are profuse sweating, priapism, bradycardia, increased salivary and bronchial secretions and vomiting. Adrenergic symptoms are transient hypertension followed by hypotension, tachycardia, tachypnoea, pulmonary edema and circulatory failure in later stages. Scorpion venom blocks voltage dependent inactivation of sodium channels, resulting in intense persistent voltage depolarization of autonomic nerves with massive release of catecholamines from adrenal medulla and parasympathetic and sympathetic nerve endings.