In the two main types of irritable bowel disease (Crohn’s and Ulcerative Colitis) the damage to the gut lining is on such a scale that it can be seen when a colonoscopy or an endoscopy is carried out. These large-scale changes are macroscopic, however as the name suggests, the damage found in Microscopic colitis is small, microscopic.
Microscoptic colitis is most commnonly seen in women over the age of 60 and while it may not be associated with a reduction in life expectancy but as with other digestive issues quality of life can be drastically reduced. Chronic watery diarrhoea is the most common symptom and occurs in 7.5% of this group and it is not uncommon to experience up to 15 bowel movements a day. Other symptoms include bloating and pain, nausea, fatigue and weight loss.
You’re more likely to develop Microscopic colitis is you have a history / family history of autoimmunity (particularly coeliac disease), habitual smoking and regular use of a range of medication which include NSAIDs, proton pump inhibitors (ie omeprazole), beta blockers, or statins. Changes in the bacteria in the gut also seem to play a role especially where beneficial anti-inflammatory species of bacteria are reduced and levels of pro-inflammatory bacteria increase.