Inflammatory bowel disease (IBD) is the a chronic inflammatory disorder of the bowels characterized by periods of acute flareups (active) and mildly symptomatic or asymptomatatic periods (remission). The two main types of inflammatory bowel disease, Crohn’s disease and ulcerative colitis, are largely the same but there is distinct differences in the distribution, histopathology and clinical features. Ulcerative colitis, the more common form of IBD, is isolated to the rectum and colon whereas Crohn’s disease which mainly involves the colon and ileum of the small intestine may affect any part of the alimentary tract. Inflammatory bowel disease is a difficult condition to treat and manage and both surgical and medical treatment (the use of medication) is primarily directed at reducing the severity of symptoms during active phases and decreasing the frequency of these flareups.
Treatment, both medical and surgical, should be incorporated with dietary and lifestyle changes, although diet modification is of limited value in inflammatory bowel disease.
Medications for Inflammatory Bowel Disease
Medical treatment is determined by the clinical presentation at the time. Acute flareups require symptomatic treatment although this has to be limited in severe acute phases. Therapy during remission may be directed at preventing an acute flareup or even managing the odd mild persistent symptom.
Acute Flareups in IBD
Symptomatic treatment will depend on the use of one or more of these drugs depending on the clinical presentation at the time :
- Antidiarrheals such as loperamide or combination dipheoxylate and atropine for controlling diarrhea, reducing frequency of bowel movements and urging. Methylcellulose or psyllium powder may also be effective for mild diarrhea.
- Antispasmodics such as dicyclomine to relieve intestinal cramping.
- Pain relievers such as acetaminophen may be effective for mild pain but aspirin, ibuprofen and narcotics should be avoided particularly in the long term.
The use of these medications in a severe acute flareup can exacerbate the condition and lead to complications. In-hospital management may be the preferred option in these instances. Many of the drugs discussed below under step-wise medical treatment is useful for acute flareups, inducing remission and maintaining remission (long term management).
Step-Wise Medical Treatment
Long term management is intended to prevent flareups or at least reduce the frequency and severity. In terms of medication, a step-wise approach to therapy is employed where the next step is commenced once the patient fails to respond to the current regimen.
Step 1 – Aminosalicylates and Antibiotics
Aminosalicylates are derivatives of 5-aminosalicylic acid that are used as for its anti-inflammatory action in both treating flareups and maintaining the disease in remission. The different types of aminosalicylates used includes :
All of these aminosalicylates appear to be equally effective and a better response to these drugs is noted in ulcerative colitis with Crohn’s disease. It is more effective to prevent recurrence after surgery in Crohn’s disease. Aminosalicylates may be administered orally or rectally (enema or suppository).
Antibiotics are more frequently used in Crohn’s disease as it is more likely to cause antibiotic-associated colitis in ulcerative colitis. Nevertheless, it is used sparingly in ulcerative colitis, particularly prior to surgery. Antibiotics have been shown to induce remission in inflammatory bowel disease (IBD). The more commonly used antibiotics are :
Step 2 – Corticosteroids
Corticosteroids are anti-inflammatory drugs that are useful in acute flareups and for inducing remission but not for maintaining remission. These drugs should not be used long term due to the host of side effects, many of which are serious and severe. It is, however, not uncommon for some patients to experience an acute exacerbation of the condition upon discontinuing corticosteroids if the condition has not slipped into remission before drug cessation. Corticosteroids can be administered orally, topically or intravenously with the latter being preferred in the hospital setting for its rapid action and better control of dosing.
Step 3 – Immune Modifiers and TNF Inhibitors
Immune modifiers are drugs that typically suppress the immune system thereby reducing the inflammation. These drugs may affect the white blood cell count. It is useful for both inducing and maintaining remission and so it should be used only after other measures, particularly aminosalicylates, fail to act or cannot be tolerated. Immune modifiers may also be useful in reducing dependence on corticosteroids particularly in long term management where corticosteroids should not be used for maintaining remission. These type of drugs include :
- 6-mercaptopurine (6-MP)
TNF inhibitors, also known as anti-TNF drugs or anti-TNF-alpha monoclonal antibodies, also counteract immune action by binding and neutralizing tumor necrosis factor (TNF) that is secreted by white blood cells. TNF mediates tissue damage. These drugs are more effective for Crohn’s disease but is also used in ulcerative colitis. As with immune modifiers, it has severe side effects and is not the first line of treatment. The anti-TNF agents used for IBD include :
- Certolizumab pegol
Another type of monoclonal antibody known as natalizumab acts by blocking integrin, the molecule that contributes to lymphocyte accumulation in the bowels. It is useful for Crohn’s disease but not routinely used as a step III measure because TNF inhibitors are usually more effective.
Surgery for Inflammatory Bowel Disease
Surgery is considered when medical treatment (medication) fails to act. It is curative for ulcerative colitis and therefore indicated for management where medication is ineffective. Surgery for Crohn’s disease should only be considered when the complications of IBD arises.
For ulcerative colitis, surgery may involve proctocolectomy (removal of rectum and part/entire colon). A stoma (ileostomy) is necessary to allow waste material to pass out of the small intestine (terminal end known as the ileum) and into the exterior. Another procedure that may be considered for ulcerative colitis is colectomy (surgical removal of colon) with ileoanal pouch (ileoanal anastomosis). An ileoanal anastomosis connects the terminal part of the small intestine (ileum) to the anus but a pouch is formed with the small intestine to serve as a reservoir for feces.
Since Crohn’s disease can affect any part of the alimentary tract, surgery does not have the same results as is the case with ulcerative colitis. Segmental resection of the portion of the tract that is most effective is not curative and recurrence rates may be as high as 50%. Anastomosis is necessary and this may involve the ileum to the rectum (ileorectal anastomosis) or healthy ileum to colon (ileocolonic anastomosis). Despite surgery not being curative with Crohn’s disease, patients may respond better to medication for maintaining remission after surgery.