author/s: Dr Mª Carmen Peña Cala

What is diarrhoea?

Diarrhoea is an increase in the normal frequency of defecation or a change of consistency into a more liquid form.


Types of diarrhoea, according to its duration

    • Acute diarrhoea: When its duration is less than 3 weeks in children and adults and less than 4 weeks in nursing infants.

    • Chronic diarrhoea: When the diarrhoea lasts more than 3 weeks in children and adults and 4 weeks in nursing infants. The evolution can be constant or intermittent.


Symptoms of acute diarrhoea

In the majority of cases, acute diarrhoea is caused by a infectious process or after the administration of antibiotics. It is usually accompanied by other symptoms, such as:

    • Vomiting

    • Fever

    • Headache

    • Loss of appetite

    • Muscle pain

    • Colicky abdominal pain

    • General malaise


Causes of chronic diarrhoea

Chronic diarrhoea is hard to diagnose because it can be caused by several factors:

    • Irritable bowel syndrome is the most frequent cause of chronic diarrhoea. It usually presents in an intermittent manner and its diagnosis is based on exclusion, having to rule out other causes for the diarrhoea.

    • Intolerance to lactose is also a frequent reason. In our setting, 10 to 15% of the population has partial intolerance to lactose.

    • Intestinal infections can also cause chronic diarrhoea, especially those caused by parasites.

    • Intestinal inflammatory disease is on many occasions accompanied by diarrhoea, in conjunction with blood in the stools.

    • Diseases that cause malabsorption of nutrients are also accompanied by chronic diarrhoea, as it occurs in patients with celiac disease.

    • Cancer of the colon in certain patients can also be accompanied by chronic diarrhoea.

    • Microscopic colitis is a disorder of the colon in which despite a normal endoscopy, biopsy detects a considerable inflammation that produces chronic diarrhoea.

    • Other less frequent causes are diarrhoeas that accompany other endocrine disorders, those due to drugs or food additives, or those caused by intestinal ischemia.


How is it diagnosed?

Diarrhoea is diagnosed by means of a blood test, a test of the faeces and, in some patients, after a colonoscopy to take a biopsy sample. Logically, the treatment will be customised depending on diagnosis.


How can diarrhoea be treated?

The majority of acute diarrhoeas are autolimited (they are cured by themselves), thus diagnostic studies are only recommended in case there is a high fever, general malaise, tenesmus (constant and inefficient need to defecate), diarrhoea with blood, dehydration, or an episode of over 1 week despite symptomatic treatment. On occasions, the patient will require hospitalisation in cases of severe dehydration, uncontrollable vomiting, old age, underlying severe disease or extreme general malaise.

The treatment will consist mainly in an astringent diet, no milk or derivative milk products, and in some patients, antibiotics might be necessary to control the disease.