Increased frequency, fluidity or volume of bowel movements compared to usual. Most people have occasional attacks of acute diarrhoea, usually caused by contaminated food or water or excessive alcohol consumption. Such attacks normally clear up within a day or two, whether or not they are treated. Chronic diarrhoea, on the other hand, may be the result of a serious intestinal disorder or of more general disease.
The commonest cause of acute diarrhoea is food poisoning, the organisms involved usually being STAPHYLOCOCCUS, CLOSTRIDIUM BACTERIA, SALMONELLA, E. coli O157 (see ESCHERICHIA), CAMPYLOBACTER, cryptosporidium, and Norovirus. A person may also acquire infective diarrhoea as a result of droplet infections from adenoviruses or echoviruses. Other infections include bacillary dysentery, typhoid fever and paratyphoid fevers (see ENTERIC FEVERS). Interference with the normal bacteria living in the intestine may cause acute diarrhoea, for example if someone travels to another country and acquires unfamiliar intestinal bacteria. Antibiotics can have the same effect. Drug toxicity, food allergy, food intolerance and anxiety may also cause acute diarrhoea, and habitual constipation may result in attacks of diarrhoea.
of diarrhoea in adults depends on the cause. The water and salts (see ELECTROLYTES) lost during a severe attack must be replaced to prevent dehydration. Ready-prepared mixtures of salts can be bought from a pharmacist. Antidiarrhoeal drugs such as codeine phosphate or loperamide are often advised if the symptoms are disabling and persistent. Antibacterial drugs are rarely of value but in special circumstances may be recommended by a treating physician. Persistent diarrhoea – longer than two weeks – or blood-stained diarrhoea should be investigated under medical supervision.
This is potentially dangerous. It is usually accompanied by vomiting and the result can be rapid dehydration, as infants have relatively high fluid requirements. Usually it results from acute gastroenteritis caused by various viruses, most commonly ROTAVIRUSES, but also by many bacteria. In the developed world most children recover rapidly, but diarrhoea is the single greatest cause of infant mortality worldwide. The younger the infant, the higher the mortality rate.
Diarrhoea is much rarer in breast-fed babies, and when it does occur it is usually less severe. The condition is highly infectious and, if a case occurs in a maternity home or a children's hospital, it tends to spread quickly. This is why doctors prefer to treat such children at home but if hospital admission is essential, isolation and infection-control procedures are necessary.
An infant with diarrhoea should not be fed milk (unless breast-fed, when this may continue) but should be given an electrolyte mixture, available from pharmacists or on prescription, to replace lost water and salts. If the diarrhoea improves within 24 hours, milk can gradually be reintroduced. If diarrhoea continues beyond 36–48 hours, medical advice should be sought. Any signs of moderate or severe dehydration require urgent attention; such signs include drowsiness, lack of response, loose skin (when pinched up it returns to its normal state only slowly), persistent crying, glazed or sunken eyes and a dry mouth and tongue.