Inflammatory Bowel Disease

Today's case was of a 70-year-old man with a history of possible inflammatory bowel disease who presented with a two-week history of bloody diarrhea, abdominal pain and tenesmus.  The patient was admitted to internal medicine for workup.

We spoke about a lot of valuable points:

The differential diagnosis of bloody diarrhea depends very heavily on whether the process is acute or chronic.  Acute bloody diarrhea has only three things on the differential diagnosis: infection, infection, and infection.  Chronic bloody diarrhea has a few more diagnostic possibilities:

·      Infection – this can be with bacterial organisms that cause invasive disease (e.g. Salmonella, Shigella, E. coli, Campylobacter, Yersinia, and sometimes C. difficile), rarely with viral organisms in an immunocompetent host, but CMV is certainly seen, occasionally with fungal or parasitic organisms like E. histolytica.

·      Inflammatory causes – this would include Crohn disease or Ulcerative colitis.  Do not discount these as diagnostic possibilities in an older individual as there is a bimodal peak in the incidence of IBD with the second peak occurring in the 6^th and 7^th decades.

·      Vascular causes – Ischemic colitis can occur as a result of global hypoperfusion as in the case of shock or selective vasopressors that can induce gut ischemia, embolic or atherothrombotic phenomena are also possible.  Microvascular causes as a result of vasculitides can also cause bloody diarrhea.

·      Drug-related – Certainly diarrhea can occur as a result of laxative overuse, but also bloody diarrhea can be the result of sympathomimetic drugs like amphetamines.  Antiplatelet and anticoagulant agents can certainly predispose to mucosal bleeding as well.

·      In our TGH population, it’s important to remember Graft-versus-host disease as well as radiation-induced colitis.

·      A myriad of other causes can lead to lower-GI bleeding including hemorrhoids, colonic angiodysplasia, microscopic colitis, and diverticular disease.

We spoke about some of the extraintestinal manifestations of inflammatory bowel disease such as:

·      Fevers and constitutional symptoms

·      Iritis/Uveitis

·      Arthritis (of which there is an oligoarticular variant related to disease activity, and a polyarticular variant not related to disease activity)

·      Skin manifestations: Erythema nodosum and pyoderma gangrenosum

·      Anemia

·      Primary sclerosing cholangitis (UC only)

·      Apthous ulcers (Crohn only)

·      Sequele of chronic inflammatory processes: Deep-vein thrombosis, AA amyloidosis

·      Colon cancer (risk is much greater with UC)

·      Fistulization (risk much greater with Crohn)

We also spoke about differentiating factors between the two inflammatory bowel diseases:

·      Crohn disease can involve any portion of the GI tract from mouth to anus, and typically spares the rectum whereas UC is limited to the rectum and colon

·      Crohn disease can have “skip lesions” where portions of discontinuous GI tract are affected whereas UC tends to start in the rectum and continue proximally until normal mucosa is reached

·      Crohn disease causes transmural granulomatous inflammation and fistulization whereas UC causes mucosal inflammation.

·      The pathologic and endoscopic appearances of the colonic lesions can be quite different

Ultimately, treatment of these patients will be done in consultation with a specialist in IBD.  The treatment differs quite greatly between the two entities, and immunomodulatory medication such as TNF-alpha inhibitors are becoming more popular choices.  The general rule when someone presents to the emergency department with something compatible with an IBD flare would be to first ensure stability by giving resuscitation fluid and treating overt consequences of hypovolemia.  Then, infection and major consequences such as toxic megacolon are ruled out, as these are life threatening emergencies.  If an infectious etiology isn’t identified quickly, then the chances are that the patient requires immunomodulatory therapy usually with steroids, followed by a maintenance agent.  In UC, the severity of the flare tends to dictate the therapy – milder flares are treated with 5-ASA preparations, whereas more serious flares require oral or parenteral glucocorticoids.

Further Reading:

Greenstein, A. J., Janowitz, H. D., & Sachar, D. B. (1976). The extra-intestinal complications of Crohn's disease and ulcerative colitis: a study of 700 patients. Medicine, 55(5), 401-412.

Podolsky, D. K. (1991). Inflammatory bowel disease. New England Journal of Medicine, 325(13), 928-937.