Fluid deficiency in the body caused by the loss of much liquid. This loss of fluid can arise as a result of severe vomiting and/or diarrhoea, but also through the excessive production of urine and/or too low a fluid intake. Children are especially susceptible to dehydration. Acute vomiting and diarrhoea with considerable loss of liquid are often the result of infection caused either by a virus (gastric flu) or a bacterium. Bacterial infections, in particular, can give rise to dehydration, and some examples are tropical forms such as cholera and dysentery. Other forms of diarrhoea are not usually serious enough to lead to dehydration. Dehydration caused by increased urine production is a complication of diabetes mellitus. Dehydration in intestinal diseases is characterized by reduced urine production (dryish nappies), skin turgor (doughy skin; when a wrinkle is made in the skin it remains there a long time), sunken eyes and, in serious cases, drowsiness which can pass into a coma. In babies, another important symptom of dehydration is that the fontanel is sunken. Disturbances in electrolyte balance and in the degree of acidity, as well as a thickening of the blood, can be detected by laboratory tests. Treatment consists of administering liquid and electrolytes, mostly by means of an intravenous drip. Substances which correct the pH balance must often be given as well. Condition of lowered consciousness, associated with disorientation, confusion, hallucinations, compulsive movement and often great fear. The cause is always physical: infectious diseases (such as typhoid), pneumonia, heart conditions and oxygen deficiency in the brain. Delirium also occurs in poisoning, as in alcoholic-delirium tremens and uraemia. Children may respond to fever with delirium. Treatment is according to symptoms and the underlying illness.