Diarrhoea

According to the World Health Organization (WHO) and UNICEF, there are about two billion cases of diarrhoeal disease worldwide every year, and 1.5 million children younger than 5 years of age perish from diarrhoea each year, mostly in developing countries. This amounts to 18% of all the deaths of children under the age of five and means that more than 4000 children are dying every day as a result of diarrhoeal diseases.

Diarrhoea is both a symptom and a sign. As a symptom, diarrhoea is most often described as a decrease in stool consistency and an increase in stool volume marked frequency, urgency and faecal incontinence. As a sign, diarrhoea is characterised by an abnormal increase in stool water secretion.

• The duration of diarrhoea is of significant clinical importance: Most acute diarrhoeas (< 2 weeks) are caused by microbial pathogens and typically resolve independent of intervention. Chronic diarrhoea (lasting more than 2 weeks) is unlikely to be infectious.
• The presence of blood in the stools suggest inflammation, neoplasm, ischaemia, or infection.
• Large-volume diarrhoea suggests small bowel or proximal colonic disease, and frequent small stools with associated urgency suggests left-sided colonic and/or rectal disease.
• Current and recent medications (e.g. antibiotics, antacids and nutritional supplements) and alcohol intake should be reviewed.
• The social history should include travel, source of drinking water (treated city water or well water), consumption of raw milk in rural populations, exposure to farm animals and sexual practices.
• Familial occurrence of celiac disease, inflammatory bowel disease, or multiple endocrine neoplasia syndromes should be considered.
• Physical examination in acute diarrhoea is helpful in determining severity of disease and hydration status.

Acute diarrhoea has < 2 weeks duration and is most commonly caused by invasive or non-invasive pathogens and their enterotoxins.

Acute noninflammatory diarrhoea

• Watery, non-bloody
• Usually mild, self-limited
• Caused by a virus or non-invasive bacteria
• Diagnostic evaluation is limited to patients with diarrhoea that is severe or persists beyond 7 days

Acute inflammatory diarrhoea

• Blood or pus, fever
• Usually caused by an invasive or toxin-producing bacterium
• Diagnostic evaluation requires routine stool bacterial cultures in all and testing as clinically indicated for Clostridium difficile toxin, ova and parasites.