A condition in which a person’s water content is at a dangerously low level. Water accounts for about 60 per cent of a man’s weight and 50 per cent of a woman’s. The total water (and mineral salts and other substances dissolved in the body’s fluids) content must be kept within fairly narrow limits for healthy functioning of cells and tissues. Dehydration occurs due to inadequate intake of fluids or excessive fluid loss. The latter may occur with severe or prolonged vomiting or diarrhoea or with uncontrolled diabetes mellitus, diabetes insipidus, and some types of kidney failure. Children are especially susceptible to dehydration by diarrhoea. Severe dehydration causes extreme thirst, dry lips and tongue, an increase in heart rate and breathing rate, dizziness, confusion, lethargy, and eventual coma. The skin looks dry and loses its elasticity. Any urine passed is small in quantity and dark-coloured. If there is also salt depletion, there may also be headaches, cramps, and pallor. Bottled mineral water can help maintain the intake of salts. For vomiting and diarrhoea, rehydration therapy is needed; salt and glucose rehydration mixtures are available from chemists. In severe cases of dehydration, fluids are given intravenously. The water/salt balance is carefully monitored by blood tests and adjusted if necessary.


Online Medical Dictionary: Your essential reference to over 5000 medical terms.