1. Primary dehydration: diagnostic criterion is increase of plasma sodium concentration. Dehydration results from: non-renewable, excessive water loss (fever, osmotic diuresis, and diarrhoea), water deprivation (“no ingestion” prescription, coma).
2. Hypoglycaemia (low blood sugar).
3. Infectious diseases, especially those with pronounced asthenic syndrome.
4. Cardiac decompensation as a result of sudden decrease of the heart pump function.
5. Liver diseases.
6. Shock, collapse (sudden drop in blood pressure).
7. Dilution of cardiac glycosides and other drugs.