Definition of

Diarrhoea is the output of at least three soft or liquid stools a day, or at an abnormal rate for the individual.

It is generally the symptom of a gastrointestinal infection, which is most often viral in origin.

Continue reading

The infection is transmitted through the consumption of contaminated water or food, or, more often, from one person to another (interhuman contamination).
Severe diarrhoea leads to the loss of fluids and salts (electrolytes), and can be fatal, especially in young children and malnourished or immunosuppressed individuals.


Diarrhoea is often accompanied by abdominal pain and vomiting. Moderate fever may also occur.


Diarrhoea is said to be acute when it has been present for less than two weeks. In the majority of cases, acute diarrhoea comes on suddenly. It generally lasts less than a week and does not recur in the short term.


Each year, in France, 5% of the population see a general practitioner for acute diarrhoea. Norovirus (the most common culprit) or Rotavirus in very small children, can cause congestion in medical clinics and emergency services with a winter peak.


Diarrhoea is haemorrhagic in one percent of cases. Acute diarrhoea generally resolves spontaneously or with symptomatic treatment in less than 5 days. Sick leave is prescribed in a third of cases.


General aspects – pathophysiology

Diarrhoea occurs by way of water and electrolyte hypersecretion, which can be associated with an acceleration in bowel movements. The water present in the gastrointestinal tract does not have time to be reabsorbed and the stools become soft or liquid.

Changes in diet, when travelling for example, can cause diarrhoea. It also happens that certain drugs and dietary intolerances can be responsible for episodes of diarrhoea.

Infectious causes

In developed countries, around one episode of acute gastrointestinal illness (vomiting and/or diarrhoea) is recorded per inhabitant per year. Most cases last less than 24 hours and are often incorrectly attributed to a food cause, whereas the vast majority are viral in aetiology.

Food causes may be considered in the event of simultaneous cases, particularly during meals served to groups. They generally correspond to short-lived toxicity due to bacterial toxins. They do not require a medical consultation unless associated with dehydration.

Iatrogenic causes (drug-induced)

Some forms of diarrhoea are caused by antibiotics. 10% of patients on antibiotics notice a change in their bowel habit.

This form of diarrhoea is generally due to digestive metabolic changes, including a reduction in the fermentation capacity of the colon’s bacterial flora (dysbiosis). It is benign and will disappear when the treatment is stopped.


Global management

In most cases, the general practitioner will intervene during the first 48 hours of the diarrhoea’s clinical course. He/she will start by checking the circumstances in which the diarrhoea came on and the impact on the patient’s general clinical state, with particular reference to the risk of dehydration. With some exceptions, it is sufficient to recommend hydration, a special diet and hygiene habits (hand hygiene, not sharing toiletries and cutlery, disinfecting toilets), and to prescribe symptomatic treatment.

Symptomatic treatment

The treatment of dehydration involves compensating water and salt losses. Use oral rehydration solutions. They allow for the optimal compensation of dehydration (never use sodas or drinks containing sugar only).

As an adjunct, drugs such as anti-intestinal secretion agents allow for the rapid resolution of bothersome symptoms, while avoiding secondary constipation.
Most cases of infectious diarrhoea, particularly viral cases, disappear spontaneously in less than 5 days and do not require any additional investigations or treatment.
When acute diarrhoea lasts more than 5 days despite symptomatic treatment, it is reasonable to consider investigations. The patient is then proposed a stool culture and stool parasitology analysis.

When a gastrointestinal infection with a pathogenic bacterium is identified, antibiotics are prescribed to shorten the clinical course of the infection. Lastly, the identification of a pathogenic parasite leads the physician to select a specific antiparasitic therapy.