Sarin poisoning stems from either inhalation or direct contact with sarin, an extremely dangerous neurotoxin that acts as an acetylcholinesterase inhibitor. The clinical presentation depends on the severity of exposure, but an immediate appearance of hypothermia, convulsions, hypersecretion of glands, tremors, and weakness is observed. Death may ensue due to respiratory failure and severe airway obstruction. The diagnosis is difficult to attain and is based on clinical criteria and epidemiologic information.
Initially synthesized by humans as a weapon for chemical warfare, sarin (also known as O-isopropyl methylphosphonofluoridate) is a colorless and clear liquid that belongs to a group of highly toxic and life-threatening nerve agents [1] [2]. Similar to organophosphates, sarin behaves as an inhibitor of acetylcholinesterase (Ach); thus it produces symptoms by promoting cholinergic effects at both muscarinic (M) and nicotinic (N) receptors of the parasympathetic part of the autonomic nervous system [2] [3] [4] [5]. Sarin poisoning has been described in very few reports, mainly during the terrorist attacks in Japan during the 90's [1] [3] [6]. In addition to direct contact with its liquid form, individuals can inhale sarin as a gas and it is equally potent in both forms [2]. The clinical presentation depends on the route of exposure - dermal absorption may delay first signs for up to 18 hours, with local sweating and glandular hypersecretion, together with weakness and fasciculations being the main symptoms [2] [4]. On the other hand, instantaneous development of life-threatening symptoms such as airway obstruction, weakness and failure of respiratory muscles leading to anoxia, and convulsions is seen in the case of inhalation [2] [4]. Additional findings include miosis, hypothermia, muscle twitching, tremors, ataxia, visual deficits, cardiac abnormalities (including cardiac arrest) and coma [1] [3] [7].
Except for terrorist attack-related incidents, the diagnosis of sarin poisoning has virtually never been made in general practice. Nevertheless, nerve agents such as sarin must be considered in the differential diagnosis of sudden and life-threatening respiratory and gastrointestinal tract complaints in a cluster of patients who were in the same surroundings shortly before symptoms occurred. For this reason, history taking that reveals many individuals affected by the same symptoms might be crucial in raising suspicion. Physicians must perform a quick physical examination during which cholinergic effects of sarin poisoning must be observed - miosis, sweating, hypothermia, muscle weakness, spasms, etc. In addition, some studies have identified leukocytosis, elevated serum creatine kinase levels, hyperglycemia, hypokalemia, and hypotriglyceridemia in the laboratory workup [3].