Microscopic colitis (MC), which is comprised of lymphocytic colitis and collagenous colitis, is a clinicopathological diagnosis that is commonly encountered in clinical practice during the evaluation and management of chronic diarrhea. With an incidence approaching the incidence of inflammatory bowel disease, physician awareness is necessary, as diagnostic delays result in a poor quality of life and increased health care costs. The physician faces multiple challenges in the diagnosis and management of MC, as these patients frequently relapse after successful treatment. This review article outlines the risk factors associated with MC, the clinical presentation, diagnosis and histologic findings, as well as a proposed treatment algorithm. Prospective studies are required to better understand the natural history and to develop validated histologic endpoints that may be used as end points in future clinical trials and serve to guide patient management.
Colitis ; Colitis, Collagenous ; Colitis, Lymphocytic ; Colitis, Microscopic* ; Diagnosis* ; Diarrhea ; Health Care Costs ; Humans ; Incidence ; Inflammatory Bowel Diseases ; Natural History ; Prevalence* ; Prospective Studies ; Quality of Life ; Recurrence ; Risk Factors

Microscopic colitis (MC) is a chronic idiopathic inflammatory bowel disease presenting with chronic watery diarrhea. Epidemiologic studies from Western countries have demonstrated that it is almost as common as other classic inflammatory bowel diseases, such as Crohn's disease and ulcerative colitis. Histological examination can confirm the diagnosis and differentiate between the two main subtypes of MC: collagenous colitis and lymphocytic colitis. The pathophysiology of MC remains unknown; however, possible etiologies include genetic predispositions, autoimmunity, inflammatory responses to luminal factors such as certain drugs or bacteria, and myofibroblast dysregulations. The aim of MC therapy should take into account the severity of symptoms, impact on quality of life, and evidence from clinical trials of available medical treatments.
Autoimmunity ; Bacteria ; Colitis, Collagenous ; Colitis, Lymphocytic ; Colitis, Microscopic* ; Colitis, Ulcerative ; Crohn Disease ; Diagnosis ; Diarrhea ; Epidemiologic Studies ; Genetic Predisposition to Disease ; Inflammatory Bowel Diseases ; Myofibroblasts ; Phenobarbital ; Quality of Life

Lymphocytic colitis is a chronic inflammatory disease affecting the bowel. The clinical course of lymphocytic colitis is believed to be benign with watery diarrhoea. We report herein what is, to the best of our knowledge, the first case of lymphocytic colitis complicated by a terminal ileal mass. A 23-year-old man presented with diarrhoea. Blind biopsies of samples taken from the terminal ileum, caecum and ascending colon showed features of lymphocytic colitis. He declined treatment with budesonide or 5-aminosalicylates. He presented 14 months later with pain over the right lumbar region and nausea. Computed tomographic enteroclysis showed a focal soft tissue enhancing mass at the terminal ileum. Excision of the soft tissue mass revealed that it was reactive nodular lymphoid hyperplasia with fibrous granulation tissue. In conclusion, an untreated lymphocytic colitis may result in the formation of an inflammatory mass lesion.
Biopsy ; Budesonide ; therapeutic use ; Cecum ; pathology ; Colitis, Lymphocytic ; complications ; therapy ; Colonoscopy ; Diarrhea ; complications ; Fibrosis ; Granulation Tissue ; pathology ; Humans ; Hyperplasia ; Ileum ; pathology ; Inflammation ; Intestinal Mucosa ; pathology ; Male ; Nausea ; Tomography ; Treatment Outcome ; Young Adult

Chronic diarrhea is usually associated with a number of non-infectious causes. When definitive treatment is unavailable, symptomatic drug therapy is indicated. Pharmacologic agents for chronic diarrhea include loperamide, 5-hydroxytryptamine type 3 (5-HT3) receptor antagonists, diosmectite, cholestyramine, probiotics, antispasmodics, rifaximin, and anti-inflammatory agents. Loperamide, a synthetic opiate agonist, decreases peristaltic activity and inhibits secretion, resulting in the reduction of fluid and electrolyte loss and an increase in stool consistency. Cholestyramine is a bile acid sequestrant that is generally considered as the first-line treatment for bile acid diarrhea. 5-HT3 receptor antagonists have significant benefits in patients with irritable bowel syndrome (IBS) with diarrhea. Ramosetron improves stool consistency as well as global IBS symptoms. Probiotics may have a role in the prevention of antibiotic-associated diarrhea. However, data on the role of probiotics in the treatment of chronic diarrhea are lacking. Diosmectite, an absorbent, can be used for the treatment of chronic functional diarrhea, radiation-induced diarrhea, and chemotherapy-induced diarrhea. Antispasmodics including alverine citrate, mebeverine, otilonium bromide, and pinaverium bromide are used for relieving diarrheal symptoms and abdominal pain. Rifaximin can be effective for chronic diarrhea associated with IBS and small intestinal bacterial overgrowth. Budesonide is effective in both lymphocytic colitis and collagenous colitis. The efficacy of mesalazine in microscopic colitis is weak or remains uncertain. Considering their mechanisms of action, these agents should be prescribed properly.
Abdominal Pain ; Anti-Inflammatory Agents ; Bile ; Budesonide ; Cholestyramine Resin ; Citric Acid ; Colitis, Collagenous ; Colitis, Lymphocytic ; Colitis, Microscopic ; Diarrhea* ; Drug Therapy ; Humans ; Irritable Bowel Syndrome ; Loperamide ; Mesalamine ; Parasympatholytics ; Probiotics ; Receptors, Serotonin, 5-HT3 ; Serotonin

BACKGROUND/AIMS: Although normal endoscopic findings are, as a rule, part of the diagnosis of microscopic colitis, several cases of macroscopic lesions (MLs) have been reported in collagenous colitis, but hardly in lymphocytic colitis (LC). The aim of this study was to investigate the endoscopic, clinical, and histopathologic features of LC with MLs. METHODS: A total of 14 patients with LC who were diagnosed between 2005 and 2010 were enrolled in the study. Endoscopic, clinical, and histopathologic findings were compared retrospectively according to the presence or absence of MLs. RESULTS: MLs were observed in seven of the 14 LC cases. Six of the MLs exhibited hypervascularity, three exhibited exudative bleeding and one exhibited edema. The patients with MLs had more severe diarrhea and were taking aspirin or proton pump inhibitors. More intraepithelial lymphocytes were observed during histologic examination in the patients with MLs compared to the patients without MLs, although this difference was not significant. The numbers of mononuclear cells and neutrophils in the lamina propria were independent of the presence or absence of MLs. CONCLUSIONS: LC does not always present with normal endoscopic findings. Hypervascularity and exudative bleeding are frequent endoscopic findings in patients with MLs.
Adult ; Aged ; Colitis, Collagenous/*pathology ; Colitis, Lymphocytic/complications/*pathology ; Colon/pathology ; *Colonoscopy ; Diagnosis, Differential ; Diarrhea/etiology ; Female ; Humans ; Intestinal Mucosa/*pathology ; Male ; Middle Aged ; Retrospective Studies

BACKGROUND/AIMS: Although normal endoscopic findings are, as a rule, part of the diagnosis of microscopic colitis, several cases of macroscopic lesions (MLs) have been reported in collagenous colitis, but hardly in lymphocytic colitis (LC). The aim of this study was to investigate the endoscopic, clinical, and histopathologic features of LC with MLs. METHODS: A total of 14 patients with LC who were diagnosed between 2005 and 2010 were enrolled in the study. Endoscopic, clinical, and histopathologic findings were compared retrospectively according to the presence or absence of MLs. RESULTS: MLs were observed in seven of the 14 LC cases. Six of the MLs exhibited hypervascularity, three exhibited exudative bleeding and one exhibited edema. The patients with MLs had more severe diarrhea and were taking aspirin or proton pump inhibitors. More intraepithelial lymphocytes were observed during histologic examination in the patients with MLs compared to the patients without MLs, although this difference was not significant. The numbers of mononuclear cells and neutrophils in the lamina propria were independent of the presence or absence of MLs. CONCLUSIONS: LC does not always present with normal endoscopic findings. Hypervascularity and exudative bleeding are frequent endoscopic findings in patients with MLs.
Adult ; Aged ; Colitis, Collagenous/*pathology ; Colitis, Lymphocytic/complications/*pathology ; Colon/pathology ; *Colonoscopy ; Diagnosis, Differential ; Diarrhea/etiology ; Female ; Humans ; Intestinal Mucosa/*pathology ; Male ; Middle Aged ; Retrospective Studies

No abstract available.
Colitis, Collagenous/*pathology ; Colitis, Lymphocytic/*pathology ; *Colonoscopy ; Female ; Humans ; Intestinal Mucosa/*pathology ; Male

No abstract available.
Colitis, Collagenous/*pathology ; Colitis, Lymphocytic/*pathology ; *Colonoscopy ; Female ; Humans ; Intestinal Mucosa/*pathology ; Male

"Cat scratch colon" is a gross finding characterized by hemorrhagic mucosal scratches on colonoscopy. It is usually associated with a normal colon and is rarely associated with collagenous colitis. In a previous report, cat scratch colon was noted in the cecum and ascending colon, but has also been observed in the distal transverse colon. The patient in this study was also diagnosed with ischemic colitis that may have played a role in the development of cat scratch colon.
Animals ; Barotrauma ; Cats ; Cecum ; Colitis ; Colitis, Collagenous ; Colitis, Ischemic* ; Colon ; Colon, Ascending ; Colon, Transverse ; Colonoscopy ; Humans ; Ischemia

BACKGROUND/AIMS: Microscopic colitis is characterized by chronic watery diarrhea with specific pathological changes that can be diagnosed by microscopic examination. We performed immunohistochemical analysis of proinflammatory cytokines to investigate the pathogenic mechanism of microscopic colitis. METHODS: This study consisted of six patients with lymphocytic colitis, six patients with collagenous colitis, and six patients with functional diarrhea but normal pathology. We performed an immunohistochemical analysis of the colonic mucosal biopsies to assess the expression of cyclo-oxygenase-2, interleukin-17, nuclear factor-kappaB, interferon-gamma, inducible nitric oxide synthase, and tumor necrosis factor-alpha. We compared the quantity score of immunohistochemical staining among the groups. RESULTS: The microscopic colitis group showed significantly higher expression of cyclo-oxygenase-2, interleukin-17, nuclear factor-kappaB, and interferon-gamma compared with the control group. Cytokine expression was similar between collagenous colitis and lymphocytic colitis. However, the expression of cyclo-oxygenase-2 was higher in collagenous colitis. CONCLUSIONS: Proinflammatory cytokines, including interleukin-17 and interferon-gamma, are highly expressed in microscopic colitis. The expression of cyclo-oxygenase-2 was higher in collagenous colitis than in lymphocytic colitis. This study is the first on interleukin-17 expression in microscopic colitis patients.
Biopsy ; Colitis, Microscopic/*metabolism ; Colon/pathology ; Cyclooxygenase 2/*metabolism ; Cytokines/metabolism ; Diarrhea/metabolism ; Humans ; Interferon-gamma/metabolism ; Interleukin-17/*metabolism ; Intestinal Mucosa/pathology ; NF-kappa B/metabolism ; Nitric Oxide Synthase Type II/*metabolism ; Tumor Necrosis Factor-alpha/metabolism