IBD - Definition
Inflammatory bowel disease is a chronic condition where there is inflammation of the large and or small intestine without a definite cause, which has a tendency to recur. The commonest finding on sigmoidoscopy is edema, granularity, and tendency to bruise and bleed to touch.
Types of IBD
The various type of IBD are
- Ulcerative colitis (UC)
- Crohn's disease (CD)
Causes of Inflammatory Bowel Disease
The exact cause of IBD is not known. However, are the pointers towards this hypothesis. It may be that there is no single cause, and there may be more than one cause, acting in unison. The causes of IBD are:
IN ULCERATIVE COLITIS:
Infection: No specific organism is isolated in patients with UC but E.coli and its strains may be releasing certain enzymes and other products that may damage the colonic mucosa. Thus, E.coli strains isolated from UC patients showed that they released certain menotropins and microtones as compared with patients with a normal colon. It has been recently reported that in patients who recover from UC, the E.coli is adhered to colonic epithelial cells and can initiate damage.
Food allergy: It has been suggested that milk might exacerbate UC which has been shown by Trulous et al; it has observed that 20% of patients may benefit from a milk-free diet. Many studies have shown an increased number of antibodies to milk proteins but not IgE antibodies.
Environmental: Apart from infectious agents and diet, there are other environmental factors that can cause IBD. They are:
- Smoking
- Oral contraceptions
Smoking: This increases the risk of Crohn's disease. Smoking has an effect on the colonic mucosa and on its mucus production. There is a less mucous glycoprotein synthesized by nonsmoking patients as compared with smoking patients. Smoking alters the colonic mucosal blood flow and decreases mucosa permeability.
IN CROHN'S DISEASE
Infections: No specific organism has been isolated for Crohn's but now mycobacteria paratuberculosis has attracted attention. The PCR method has identified mycobacterial TB DNA in the intestinal tissue of Crohn's disease.
Diet: There is an array of antibodies against food antigens, such as milk proteins & bakers yeast in Crohn's disease patients. In another study, it was found that titanium, presumably of dietary origin in the intestinal transmural inflammatory infiltration of CD patients and in the Peyers patches suggested that dietary products are capable of being incorporated in the internal milieu
Genetics: A week association has been found between Crohn's disease and HLA - A2, HLA-DR4, DR1-DQ5, and an inverse correlation with HLA-A11 & HLA-DR3. Association of the Crohn's with a genetic disease has also been used as indirect evidence. The diseases are ankylosing spondylitis, tyrosine positive albinism, and Turours syndrome. An increased incidence of chromosomal breaks has been found in Crohn's disease patients compared with normal suggesting that inherited chromosomal fragility may be a factor in CD
Immune System: The normal gut flora is capable of suppressing the inflammatory process in the gut, but in CD this domain - regulation method is lost, and therefore there is an intense inflammatory process. The gut epithelial cells are dysregulated i.e. the normal intestinal epithelium contains MHC class II and HLA DR-DP, which are important in processing other antigens. This distribution is changed on the GI tract more so in the gut (intestine) in CD patients. The cells which usually stimulate proliferation of T suppressor cells in fact stimulate proliferation of T-helper cells. It is these T-helper cells which stimulate the cascade of immense activation.
Psychosocial factors: They represent a combination of external & internal factors. However, Crohn's is not considered a major psychosomatic disease in etiology.
Presentation
Apart from diarrhea and blood in stools, other manifestations are:
Ulcerative colitis: The extra-intestinal manifestations are the same as Crohn's disease but in some ways, they vary. The eyes, mouth, skin, joints are involved more frequently in UC. Liver disease (Primary sclerosing cholangitis) is seen in 3% of all patients.
The other rare associations are pericarditis with or without effusion and amyloidosis.
Crohn's disease: Patient may have obstruction, fistula formation (they can develop entero-enteral fistula, enterovesical fistula enterovaginal fistula and enterocutaneous fistula) and intra-abdominal abscess. The extra-intestinal manifestation will be
- Colitis related
- Consequence of small bowel pathophysiology
- Miscellaneous
- Colitis Related: Peripheral arthropathy, erythema nodosum, episcleritis, fatty liver, aphthous ulcers (10%), pyoderma gangrenosum (1-2%). Clubbing, pelvis osteomyelitis and osteomalacia.
- Consequences of small bowel pathophysiology: Malabsorption, gall stone formation (15-30%). Steatorrhea, diarrhea, bacterial overgrowth may lead to surgical resection. Pancreatitis.
- Miscellaneous: Amyloidosis, thrombo-embolic phenomenon, hepato biliary disease - primary sclerosing cholangitis.
1/4th of patients present with CD before 20 years of age. Arthritis and arthralgia are seen in about 15% of children. There may also be growth failure, anemia, and delayed puberty.
Investigations
Crohn's disease:
- Usually presents as abdominal pain, may have frequent stools and blood in stools.
- Routine hemogram, stool - routine and microscopy.
- On Clinical suspicion - Endoscopy - appearance & biopsy
- Barium contrast studies - barium enema
- Ultrasonography
- CT Scan may help
Ulcerative colitis:
- Usually presents as bloody diarrhea.
- Routine hemogram, stool - routine and microscopy.
- C - reactive protein (CRP), albumin - for follow-up and prognostication.
- Sigmoidoscopy/Colonoscopy - appearance & biopsy
- Radiology - Barium Enema
Treatment
The treatment of IBD consists of using 5-ASA and if necessary steroids. These drugs have had excellent results and have saved the lives of thousands of patients.
Can IBD be cured? Does it require life long treatment?
The word "cured" may not apply. However, the patient remains symptom-free or in remission for a long time. Theoretically, patients would require life long treatment.
Complications
Normally Inflammatory Bowel disease is not a serious condition. However, occasionally it can land up in life-threatening complications.
The commonest minor complications are:
- Anemia
- Nutritional deficiency
- Weight loss
The major complications are severe bleeds or toxic megacolon.