Introduction: Changes in plasma osmolality may occur during acute intestinal infections due to dehydration (loss of water and/or electrolytes). Depending on whether the water and electrolyte deficit is primary, or a proportional loss of water and electrolytes, dehydration can be classified into three categories: hypertonic, hypotonic and isotonic.
Material and methods: Thirty (30) patients with food poisoning were included in this research. All patients were hospitalized because of frequent vomiting, with resultant dehydration. A diagnosis of food poisoning was made based on the clinical picture, short incubation period and positive epidemiological history. Plasma osmolality was measured by a freezing point depression with an osmometer, while effective plasma osmolality was determined by using the following formula: EPO (eff. plasma osmolality) = 2 x serum sodium concentration + serum glucose level. Apart from plasma osmolality, other parameters were also measured in patients' sera: sodium, chloride, potassium, urea, glucose and hematocrit. In order to follow-up the changes in these parameters, they were also measured after treatment of the gastrointestinal disorder. Statistical analysis was performed using the equality of mean values for 2 basic groups.
Results: The statistical results showed that the values of total and effective plasma osmolality (TPO and EPO) among patients with gastrointestinal disorders were not significantly higher than values after the alimentary infection.
Discussion: Such results suggest that food poisoning is associated with disorders of water and electrolyte metabolism, that is isotonic type of dehydration.