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Chronic diarrhoea

Diarrea crònica

It is estimated that more than 5% of the population suffers from chronic diarrhoea, a condition which lasts for four or more weeks, and that close to 40% of sufferers are over the age of 60. Normal stool frequencies vary from three times a week to three times a day. Diarrhoea may be defined as reduced consistency and increased fluidity of stools, bowel movements causing abdominal cramps or discomfort or increased stool frequencies. Consistency of stools is determined according to the Bristol stool scale, a specially designed visual chart that classes stools under 7 categories, according to form and weight. 


Medical history to take into account when making a diagnosis

An evaluation has to be made of the presence: 

  • Family history of conditions such as coeliac or inflammatory bowel disease which may present a familial predisposition.
  • Personal history of travels to endemic areas, risky sexual and other practices. 
  • Systemic or neurological diseases that cause digestive motility alteration and which may be associated with diarrhoea, such as diabetes mellitus.
  • History of previous gastrointestinal surgery, such as cholecystectomy and bowel resections.
  • Use of medicines that may cause diarrhoea as a side effect or chewing gum or eating sweets with a high sorbitol content.


Causes of chronic diarrhoea 

The list of possible causes for chronic diarrhoea is extensive (see Table 1 of the attached document “Chronic Diarrhoea: Definition, Classification and Diagnosis”) and numerous tests often need to be carried out before a final diagnosis can be made.


Symptoms, signs and laboratory test abnormalities suggesting organic causes 

The most frequent causes of chronic diarrhoea in our environment are bile acid malabsorption and functional disorders, above all irritable bowel syndrome and intolerance to carbohydrates such as lactose.  

It is useful, from a clinical-practice perspective, to class patients with diarrhoea according to whether they present characteristics that suggest “functionality” – a diarrhoea that appears without an organic cause justifying it – or “organicity". This distinction is important, as the two situations’ diagnostic approach and treatment obviously differ. 

Where an organic disease is suspected, preferential action often has to be taken, in contrast to a suspected functional disorder, which may defer the diagnostic procedure somewhat.

Symptoms and alarm signs where potentially serious organic diseases causing chronic diarrhoea need to be ruled out first are: 

  • Appearance of fever.
  • Presence of blood in stools.
  • Significant loss of weight, in the absence of concomitant depressive syndrome.
  • Recent start of symptoms or change in their previous characteristics.
  • Appearance at an advanced age, from 50 on.
  • Family history of cancer of colorectal polyps.
  • Presence of nocturnal diarrhoea.
  • Diarrhoea that persists after fasting.
  • Abundant stools or stools that float in water.
  • Physical examination anomalies such as cutaneous pallor, hepatosplenomegaly, adenopathy, abdominal masses, etc.
  • Presence of anaemia, macrocytosis, hypoprothrombinaemia, hypoalbuminaemia or other laboratory test abnormalities such as increased globular sedimentation velocity (GSV) or reactive C protein.
  • A positive stool occult blood test and raised faecal calprotectin indicative of bowel inflammation.


Typical treatment

  • Symptomatic treatment: there are numerous types of treatment for chronic diarrhoea. The best known are opiates such as loperamide and codeine.  
  • Disease-altering treatment: once the underlying cause has been identified, the treatment should be as specific as possible not just to ensure symptomatic improvements but also to alter the natural course of the disease.  



There are currently no specific recommendations for preventing the appearance of this disease. We recommend:

  • Lead a healthy life.
  • Do regular physical exercise.
  • Control your daily-life stress.
  • Keep to a healthy diet.
  • Use antibiotics correctly.
  • Adopt measures to avoid contagions and infections you are at risk of being exposed to when visiting certain areas or countries.


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