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Microscopic Colitis

Essentials

  • Microscopic colitis is discovered in about 10% of patients who have undergone colonoscopy for chronic diarrhoea.
  • Diagnosis is based on histological biopsy samples collected during a colonoscopy.
  • The most common subtypes: collagenous colitis and lymphocytic colitis
  • Aetiology and pathogenesis are unknown.
  • A benign disease, varied clinical course, medication only if necessary

Epidemiology

  • Incidence about 10 new cases/100 000 person years
    • More common in women than in men
  • Occurrence is more common after the age of 50 years and increases with age, but the disease may also occur in children.

Symptoms

  • Chronic non-bloody diarrhoea
    • Long-term or reoccurring
  • Abdominal bloating, flatulence, bowel urgency, incontinence
  • Weight loss, lethargy

Diagnosis

  • Colonoscopy
    • The endoscopic view often has a normal appearance.
    • Tissue biopsies must always be taken if diarrhoea is the principal symptom.
  • Histological analysis will reveal, among other things, inflammatory changes in the lamina propria and degeneration of the epithelium.
    • Collagenous colitis: thickened subepithelial collagen layer
    • Lymphocytic colitis: increase in the number of intraepithelial cells, mainly lymphocytes
    • Inflammatory changes throughout the entire large bowel, most markedly at its start and midsection, sometimes also in the ileum
  • Laboratory investigations are those used in the basic examination of any patient with diarrhoea; see also article Prolonged diarrhoea in the adult Prolonged Diarrhoea in Adults.
    • Basic blood count with platelet count, ESR, CRP, sodium, potassium, creatinine
    • Thyroid-stimulating hormone (TSH), transglutaminase antibodies
    • Faecal calprotectin normal or elevated

Differential diagnosis

Associated conditions and medicines

  • The incidence of autoimmune diseases is high among patients, particularly coeliac disease must be excluded
  • Rheumatic conditions, collagenosis, different pain syndromes, fibromyalgia
  • Possible link with medicines: aspirin, other NSAIDs, proton pump inhibitors (PPI) or H2-receptor blockers; SSRIs

Treatment

Other medicines, if symptomatic medication and treatment are not sufficient

  • Cholestyramine is effective in some patients even in the absence of co-existing bile acid malabsorption: (½-1 sachet 1-3 times daily)
    • The patient may try stopping the medicine during an asymptomatic phase
    • Note! Cholestyramine affects the absorption of other medicines
  • Glucocorticoids (bear the adverse effects in mind)
    • Budesonide SIR
      • Administered as a course with gradually decreasing doses
        • E.g. 9 mg for 1-2 months, 6 mg for 1-2 months, 3 mg for 1-2 months
      • Best proven efficacy, but the symptoms often recur when the medication is discontinued
    • Budesonide MMS
      • Budesonide is released in the colon.
      • Used in ulcerative colitis
      • Evidence is so far lacking for the use in microscopic colitis.
    • Courses of prednisolone if the above medication proves ineffective
    • 5-ASA medications as in ulcerative colitis
  • Sometimes azathioprine, methotrexate, TNF-alpha inhibitors
    • In the presence of very severe symptoms, continual need for glucocorticoids; in specialist care!
  • National legislation as regards the reimbursement of medicines applies.

Prognosis and follow-up

  • The prognosis is good.
    • Spontaneous remissions and several years with no symptoms are possible
  • Not known to increase the risk of, for example, bowel cancer.
    • No need for endoscopic follow-up
  • Evaluation and management by a specialist is indicated if the symptoms are troublesome and the patient needs repeated courses of budesonide.

Related Keywords

ATC Code:

H02AB06

A07EA06

A07DA03

C10AC01

A07EC01

L04AX03

A07EC02

L04AX01

Primary/Secondary Keywords