Diarrhoea

Diarrhoea, apart from being a hard word to spell, is a common but often inconvenient gut-related symptom.

While for most people in developed countries it is more of an inconvenience, worldwide it is one of the leading causes of death for children under 5 years.

What is diarrhoea?

Diarrhoea is defined as the passage of at least 3 loose or watery stools within a 24-hour period.

It is broadly classified accorded to the duration of symptoms:
(i) Acute – less than 2 weeks
(ii) Persistent – between 2-4 weeks
(iii) Chronic – longer than 4 weeks

What causes diarrhoea?

There are many causes of diarrhoea. The most common cause is due to an infection such as a virus, bacteria or parasite that enters the digestive tract. Most infections are ‘self-limiting’ meaning they cause symptoms for a short period of time and then get better by themselves. What many of us might call a ’bout of gastro’ or ‘gastroenteritis’.

Diarrhoea that continues for longer than 1-2 weeks is less likely to be an infection and other causes need to be considered. These include:

– Irritable bowel syndrome (IBS)
– Coeliac disease
– Crohn’s disease or Colitis
– Medication-related
– Thyroid disease
– Bowel polyps or cancer
– Diet related eg. Lactose or fructose intolerance

How do you diagnose the cause of diarrhoea?

Diarrhoea that is mild and lasts only a few days does not need to be investigated. Symptoms that are severe or last longer may require some of the following tests:

(i) a stool or “poo” sample – this looks for the presence of infections including viruses, bacteria and parasites.

(ii) faecal calprotectin – this test is also performed on a stool sample and looks for inflammation. Often used if Crohn’s disease or Colitis is suspected.

(iii) A blood test – multiple tests can be performed on a blood sample and can be used to assess for coeliac disease, thyroid disease, abnormal calcium levels and anaemia as well as for the presence of inflammation (CRP).

(iv) Ultrasound/ Xray/ CT scan/ MRI – sometimes these tests are performed to assess the abdominal organs and to look for evidence of inflammation.

(v) Colonoscopy – this test involves passing a thin flexible tube, with a tiny camera at the end, into the bowel to investigate the lining of the bowel.. It allows polyps, cancers and inflammation to be ruled out, as well as allowing biopsies (tissue samples) to be taken.

How do you treat diarrhoea?

The treatment for diarrhoea should be targeted at the underlying cause. Most mild infections are self-limiting, while more serious cases may require antibiotics and even hospitalization.

Depending on the cause, other treatments may range from dietary modification, to stronger medication or even surgery.

Controlling symptoms: There are also medications available that decrease the severity of diarrhoea by slowing bowel movements and decreasing the amount of water lost from the intestines. Imodium and Gastrostop are two common brands that contain the drug loperamide, which is often used by travellers who want to limit the inconvenience of a bout of diarrhoea. Other medications that can be used to decrease diarrhoea symptoms (until the underlying is found) include: Lomotil, Clonidine, Codeine, Cholestyramine and Bismuth Subsalicylate.