Collagenous colitis is an inflammatory bowel disease affecting the colon specifically with peak incidence in the 5th decade of life, affecting women more than men. Its clinical presentation involves watery diarrhea in the absence of rectal bleeding. It is often classified under the umbrella entity microscopic colitis, that it shares with a related condition, lymphocytic colitis. Signs and symptoms
Microscopic colitis causes chronic watery diarrhea with greater than 10 bowel movements per day. Some patients report nocturnal diarrhea, abdominal pain, urgency, fecal incontinence, fatigue, dehydration and weight loss. Patients report a significantly diminished quality of life. Causes
The cause of collagenous colitis is unknown. Diagnosis
On colonoscopy, the mucosa of the colon typically looks normal, but biopsies of affected tissue usually show deposition of collagen in the lamina propria, which is the area of connective tissue between colonic glands. Radiological tests, such as a barium enema are also typically normal. Treatment
First line treatment for collagenous colitis is the use of budesonide, a steroid that works locally in the colon and is highly cleared by first pass effect. Other medications that can be used are the following:
Bismuth agents, including Pepto-Bismol
5-aminosalicylic acid
Immunosuppressants, including azathioprine
InfliximabPilot-scale studies have shown some evidence of possible benefit for both Boswellia serrata extract and specific strains of probiotics in the treatment of collagenous colitis, although larger sample sizes are needed to confirm the results. See also
Colitis
Lymphocytic colitis
Inflammatory bowel disease
Ulcerative colitis

References


== External links ==
Plain radiography and bone densitometry can be used to assess bone involvement and the presence of osteoporosis. Endoscopy and biopsy can be useful if gut involvement is suspected. Diagnosis
Cytochemistry
Cytochemical properties of the leukemic cells must be typical of mast cell derivation (presence of metachromatic granules staining with alpha-naphthyl chloroacetate esterase, but not with peroxidase). Mast cell tryptase is an enzyme contained in mast cell granules. Mast cell numbers are best estimated by tryptase immunostaining because very poorly granulated cells may stain very weakly if at all for alpha-naphthol chloroacetate esterase. Tumor markers
The leukemic cells usually are strongly positive for CD13, CD33, CD68, and CD117. Characteristically, basophil (e.g. CD11b, CD123) and monocyte markers (CD14, CD15) are absent. The cells usually express CD2 and CD25. Malignant mast cells overexpress the anti-apoptosis gene, bcl-2. A mutation called KIT mutation is detected in most patients. Biochemistry
Total serum tryptase is elevated in mast cell leukemia. Normal total (alpha + beta) serum tryptase is approximately 6 micro g/L (range 0 to 11 micro g/L). Values of several hundred micro g/L are characteristic of mast cell leukemia. Plasma and urinary histamine levels are frequently elevated in mast cell leukemia. Histidine decarboxylase (HDC) is the enzyme that catalyzes the reaction which produces histamine from histidine. Measurement of histidine carboxylase in the marrow cells of patients with mast cell leukemia is a very sensitive marker of mast cells. Treatment
Immunoglobulin E (IgE) is important in mast cell function.