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Microscopic Colitis

Checked: 23-10-2023 by Rob Adams Next Review: 23-10-2025

Overview

Microscopic colitis is an Inflammatory Bowel Disease that affects the colon. There are two main forms of Microscopic Colitis – Lymphocytic Colitis and Collagenous Colitis. These are very similar conditions and are commonly referred to under the single name ‘Microscopic Colitis’.(1)

Microscopic colitis affects 0.12% of the population but 12.8% of those with unexplained chronic, watery diarrhoea. The median age at diagnosis is 60,reflecting an older population than those typically diagnosed with other types of inflammatory bowel disease. (2)

Who to Refer

Patients typically have profuse watery diarrhoea, often with urgency, incontinence, and nocturnal symptoms. Symptoms are generally milder than in patients with other forms of IBD and primary care investigations are usually normal (including FIT and FCP).

Diagnosis is made on histology following colonoscopy. Referral to direct access colonoscopy for patients with profuse watery diarhroea despite normal investigations is therefore appropriate.

What to do before referral

Preliminary investigations in Primary Care

Please undertake a FIT if indicated and if negative investigate as for suspected IBD initially.

Undertake a medication review

Microscopic colitis is most commonly seen in association with Sertraline use (much more so than other SSRIs), as well as to a lesser extent NSAIDs and PPIs, so a review of regular medication is recommended. In the case of Sertraline, individuals may be ok on 50mg daily, and only get symptoms when the dose is increased.

It is recommended to withdraw any medication if possible which is suspected to have triggered the onset. In the case of Sertraline, for example, this could include switching to an alternative SSRI or non-SSRI antidepressant.

Referral

Referrals for Diagnosis

Patients with suspected microscopic colitis not responding to measures in primary care should be referred for direct access colonoscopy.

Referrals for Management

If a diagnosis has been made on histology following colonoscopy then the following options are available:

Primary Care GI Service - refer via eRS to the Community GI service (InHealth). Anyone found to have microscopic colitis on a diagnostic scope at InHealth is routinely given a follow-up appointment in the clinic (GPs should not need to re-refer).
Secondary care gastroenterology clinic via eRS.

Management

Treatment is with oral budesonide (Budenofalk) 9 mg/day for an initial period of 6–8 weeks. This is an amber drug on the BNSSG Formulary and should only be prescribed on advice of a gastroenterologist or GPwER. Oral budesonide preparations should be prescribed by brand as are not interchangeable due to mode of action and licensing in IBD

Loperamide only may be appropriate for mild cases (BO<3x daily and no incontinence).

Resources

(1) Microscopic Colitis (crohnsandcolitis.org.uk)

(2) Microscopic colitis: a guide for general practice | British Journal of General Practice (bjgp.org)

With thanks to Dr Michael Sproat (GPwER in gastroenterology at InHealth) for his help in developing this page.

Efforts are made to ensure the accuracy and agreement of these guidelines, including any content uploaded, referred to or linked to from the system. However, BNSSG ICB cannot guarantee this. This guidance does not override the individual responsibility of healthcare professionals to make decisions appropriate to the circumstances of the individual patient, in consultation with the patient and/or guardian or carer, in accordance with the mental capacity act, and informed by the summary of product characteristics of any drugs they are considering. Practitioners are required to perform their duties in accordance with the law and their regulators and nothing in this guidance should be interpreted in a way that would be inconsistent with compliance with those duties.

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