Crohns Disease Medical Disability Guidelines
Crohn’s disease is a transmural inflammatory process. The terminal ileum is the most common site of the disorder but it may occur in any part of the GI tract.
- About two thirds of patients have some colonic involvement, and 15% to 25% of patients have only colonic disease.
- Patients often have normal bowel separating segments of diseased bowel; that is, the disease is often discontinuous.
- Complications of Crohn’s disease may involve the intestinal tract or organs unrelated to it. Small-bowel stricture and subsequent obstruction is a complication that may require surgery. Fistula formation is common and occurs much more frequently than with ulcerative colitis.
Clinical Presentation :
As with ulcerative colitis
, the presentation of Crohn’s disease is highly variable (Table 25-4). A single episode may not be followed by further episodes, or the patient may experience continuous, unremitting disease. A patient may present with diarrhea and abdominal pain or a perirectal or perianal lesion.
The course of Crohn’s disease is characterized by periods of remission and exacerbation. Some patients may be free of symptoms for years, while others experience chronic problems in spite of medical therapy.
Treatment of Crohn’s Disease :
- The goal of treatment for active Crohn’s disease is to achieve remission; however, in many patients, reduction of symptoms so that the patient may carry out normal activities or reduction of the steroid dose required for control is a significant accomplishment.
- In the majority of patients, active Crohn’s disease is treated with sulfasalazine, mesalamine derivatives, or steroids, although azathioprine, mercaptopurine, or metronidazole is frequently used.
- Sulfasalazine is more effective when Crohn’s disease involves the colon.
- Mesalamine derivatives (such as Pentasa or Asacol) that release mesalamine in the small bowel may be more effective than sulfasalazine for ileal involvement.
- Steroids are frequently used for the treatment of active Crohn’s disease, particularly with more severe presentations. Steroids are preferred for treatment of severe Crohn’s disease, mainly because these agents can be given parenterally and response to therapy may occur sooner than with other agents. Once remission is achieved, however, it may prove difficult to reduce steroid dosage without reintroduction of active disease.
- Metronidazole (given orally up to 20 mg/kg/day) may be useful in some patients with Crohn’s disease, particularly in patients with colonic involvement or those with perineal disease.
- The immunosuppressive agents (azathioprine and mercaptopurine) are generally limited to use in patients not achieving adequate response to standard medical therapy, or to reduce steroid doses when toxic doses are required. The usual dose of azathioprine is 2 to 2.5 mg/kg/day and 1 to 1.5 mg/kg/day for mercaptopurine. Up to 6 months may be required to observe a response.
- A genetic polymorphism causes deficiency of the enzyme thiopurine S-methyltransferase in some people, reduces mercaptopurine metabolism and increases the risk of bone marrow suppression.
- Cyclosporine is not recommended for Cronn’s disease except for patients with symptomatic and severe perianal or cutaneous fistulas. The dose of cyclosporine is important in determining efficacy. An oral dose of 5 mg/kg/day was not effective, whereas 7.9 mg/kg/day was effective. However, toxic effects limit application of the higher dosage.
- Methotrexate, given as a weekly injection of 5 to 25 mg has demonstrated efficacy for induction of remission in Crohn’s disease as well as for maintenance therapy.
- Infliximab, 5 mg/kg single infusion, is effective for refractory or fistulizing Crohn’s disease when given everyday for 8 weeks.
- Drug therapy for IBD is not a contraindication for pregnancy, and most pregnancies are well managed in patients with these diseases. The indications for medical and surgical treatment are similar to those in the nonpregnant patient. If a patient has an initial bout of IBD during pregnancy, a standard approach to treatment should be initiated.
- Metronidazole or methotrexate should not be used during pregnancy.