Sodium chloride

Human toxicity High NaCl intake without corresponding intake of water can lead to hypernatremia: the ratio of sodium to water exceeds normal, and both the plasma sodium concentration and the total body sodium increase. Consequently, the balance of extracellular and intracellular osmolality is disturbed, which can result in several clinical symptoms, like excessive thirst, weakness, headache, irritability, pulmonary edema, hypertention, tachycardia, and also coma at high NaCl concentrations [1]. Chloride, the other component of NaCl, is also essential for water balance and for plasma osmolality, therefore abnormalities in sodium metabolism are accompanied by abnormalities in chloride metabolism [1]. Acute poisoning with NaCl occurs often in small children due to errors in formulating infant diet (use of salt instead of sugar), or due to administration of excess salt as a means of child abuse. Salt intoxication and death also have been described when NaCl was used as an emetic [1]. Therapeutic doses of NaCl are in the range of 1 to 2 g three times daily, orally with food, or as a solution [2]. Ingestion of 0.5 to 1 g/kg will be toxic in most patients [1]. The maximum tolerated sodium intake in adult is about 15 g [2]. The estimated fatal amount of salt is about 1 to 3 g/kg [1]. When serum sodium ranges between 150 and 160 mEq/l (1 mEq, milliequivalent, is equal one mM of sodium, 23 mg; one gram of NaCl contains 17.2 mEq of sodium), which corresponds to 9-10 g/l of NaCl, the central nervous system (CNS) symptoms are common and seizures occur in approximately 10% of patients [2]. In one fatal case in an adult, with an acute oral overdose of NaCl (unknown amount, in combination with a large amount of jam), the concentration of sodium in serum was 11000 mg/l [3]. The minimum clinically measured acute lethal serum concentration of sodium, based on the data from several handbooks, was 11000 mg/l [4].