MICROSCOPIC COLITIS
ByOmar Mohammed Saleh
Assistant Lecturer of Tropical Medicine and
Gastroenterology- HUCOM-2015 .
OBJECTIVES : Definition Epidemiology Etiology Pathophysiology Diagnosis Treatment Complications and Prognosis
DIARRHEA: Diarrhea is defined in adults by abnormal
stool weight (>200 g/day), consistency (loose or liquid), and/or frequency (>3 times/day). A 4-week symptom duration is generally considered as a cutoff point to distinguish acute (<4 weeks) from chronic (>4 weeks) diarrhea.
DEFINITION: Microscopic colitis is a clinical syndrome of
unknown etiology, characterized by chronic watery diarrhea in the absence of macroscopic changes in the large bowel. Ianiro G, et al. Microscopic colitis. WJG. 2012.
Types :1. Lymphocytic colitis 2. Collagenous colitis 3. Incomplete MC4. MC not otherwise specified 5. Paucicellular LC 6. MC with giant cells7. Pseudomembranous CC8. MC with granulomatous inflammation9. Cryptal LC
EPIDEMIOLOGY:Is it a missed disease ?
OR Under diagnosed illness !!
RISK FACTORS: Female gender Older age Concomitant autoimmune diseases Solid organ transplantation
ETIOLOGY: Multifactorial Idiopathic Autoimmune phenomena; 30-50 % of MC
have autoimmune diseases Drugs Familial Possible enteric infections or toxins Smoking
REVIEW OF THE LITERATURE, MODIFIED FROM BEAUGERIE AND PRADI
Drug- induced microscopic colitis
Low likelihood Intermediate likelihood Highly likelihood
CimetidineGold saltspiasciedine
CarbamazepineCelecoxibDuloxetineFluvastatinFlutamide‘OxetoroneMadoparParoxetineSimvastatinstalevo
Acarbose Aspirin and NSAIDsClozapine EntocaponeFlavonoidLansoprazoleOmeprazole/esomeprazoleRanitidineSertralineticlopidine
PATHOPHYSIOLOGY:
PATHOGENESIS : Still not clearly understood ! Genetic; family cluster, diseases with strong
genetic component Infectious element , chronic inflammation Bile salts; increased malabsorption, response
to bile acid binding agents Abnormal immune response to luminal
antigens…….> cytotoxic tissue damage In CC, dysfunction of subepithelial
myofibroblast excessive Collagen deposition mechanical diffusion barrier
PATHOGENESIS:
DIAGNOSIS:Clinical presentation: Chronic watery diarrhea Abdominal pain Weight loss Fecal incontinence
Unremarkable findings
Physical examinatio
n Laboratory
tests Colonoscopy examination
Histopathological examination of the taken biopsy is the golden tool for making diagnosis
Lymphocytic colitis Collagenous colitis 1-Intraepithelial lymphocytosis (≥20IEL per 100 surface epithelial cells
2-Inflammation in the lamina propria consisting of mainly lymphocytes and plasma cells
3-Epithelial damage, such as flattening and detachment
4-Subepithelial collagen layer not present or less than <10um
1-Thickening of a subepithelial collagen layer of more than 10um
2-Inflammation in the lamina propria consisting of mainly lymphocytes and plasma cells
3-Epithelial damage, such as flattening and detachment
4-Intraepithelial lymphocytosis (IEL) could be present, but is not necessary for the diagnosis of CC
AWARENESS:
Colonoscopy
Biopsy from
normal mucosa
Histopahology criteria of MC
TREATMENT: Aim of treatment : to induce clinical remission and improve the patient’s quality of life.Treatment algorithm:Confirm diagnosis/ rule out other disordersWithdrawal of medications causing MCDietary changes; avoid caffeine, lactoseTrial of loperamide (mild cases)Corticosteroids: budesonide, prednisolone Probiotics Immunosuppressive drugs Surgery !
BUDESONIDE: Potent glucocorticoid with a high local anti-
inflammatory effect. A PH and time dependent formulation, enables its
release to the colon. Downregulation of cytokines with an important
role in the inflammation pathways, including nuclear factor-KappaB, TNF-α, and the interleukins 1 and 6.
15 times higher binding affinity to the glucocorticoid receptor than prednisolone.
High first-pass effect (over 90%) which is carried out by hepatic cytochrome P450 (CYP3A4 and CYP3A5) enzymes minimal systemic absorption.
COMPLICATIONS AND PROGNOSIS:
Dehydration and electrolyte imbalance Progression to IBD Colonic perforation Malignant transformation; very rare with CC Very rare toxic megacolon Prognosis: Many cases are self limited Other symptomatic cases show relapsing-
remission course Impaired HRQoL
Extra-intestinal disorders (immune-mediated); Arthritis, spondylitis, thyroiditis, pyoderma gangrenosum.
CONCLUSION: MC is not uncommon disease. Pathophysiology ??? Lab tests are non specific Biopsy is essential from normal colonoscopic
mucosa in cases of CNBD Budesonide is the only evidence based treatment
available Consider MC in celiac disease not responding to
gluten free diet. Long term outcome is good Further studies are needed !
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