Microscopic colitis refers to two related medical conditions which cause diarrhea: collagenous colitis and lymphocytic colitis. Both conditions are characterized by the presence of chronic non-bloody watery diarrhea, normal appearances on colonoscopy and characteristic histopathology findings of inflammatory cells. Signs and symptoms
The main symptom is persistent non-bloody watery diarrhea, which may be profuse. People may also experience abdominal pain, fecal incontinence, and unintentional weight loss. Microscopic colitis is the diagnosis in around 10% of cases investigated for chronic non-bloody diarrhea. Associated conditions
A higher incidence of autoimmune diseases, for example arthritis, Sjögrens syndrome, thyroid disorders, and celiac disease, has been reported in people with microscopic colitis. Associations with various drugs have been found, especially proton pump inhibitors, H2 blockers, selective serotonin reuptake inhibitors (SSRIs), and non-steroidal anti-inflammatory drugs (NSAIDs). Bile acid diarrhea is found in 41% of patients with collagenous colitis and 29% with lymphocytic colitis. Additionally, cigarette smoking has been identified as a significant risk factor of microscopic colitis. Diagnosis
Colonoscopic appearances are normal or near normal. As the changes are often patchy, an examination limited to the rectum may miss cases of microscopic colitis, and so a full colonoscopy is necessary. Multiple colonic biopsies are taken in order to make the diagnosis. Histological features of colonic biopsies indicating microscopic colitis are: greater than 20 intraepithelial lymphocytes per 100 epithelial cells and, additionally, 10-20 μm of a thickened subepithelial collagen band in collagenous colitis. Inflammation of the lamina propria, with mainly mononuclear cells, may be observed in collagenous colitis.
History
Bone marrow failure is associated with three types of diseases, Fanconi anemia (FA), dyskeratosis congenita, and aplastic anemia. Fanconi anemia is an inherited blood disorder due to abnormal breakages in DNA genes. It is linked to hyperpigmentation, which is the darkening of an area of skin or nails caused by increased melanin. According to Histopathology, "However, in about 30% of FA patients no physical abnormalities are found". Dyskeratosis congenita often affects multiple parts of the body. Individuals with this disorder usually show changes in skin pigmentations, unusual fingernail growth, and mucosa leukoplakia; the inner part of the mouth is encased with white patches that may never resolve. Aplastic anemia happens when bone marrow doesnt produce enough new blood cells throughout the body. Aplastic anemia is an acquired autoimmune disease, which occurs when the immune system mistakenly attacks and destroys healthy body tissue. == References ==