Test your medicine knowledge with the MKSAP challenge, in partnership with the American College of Physicians.

A 19-year-old woman is evaluated for a 3-month history of progressively worsening diarrhea, abdominal pain, and weight loss. Her brother was diagnosed with Crohn disease at age 16 years.

On physical examination, temperature is 37.4 °C (99.3 °F), blood pressure is 110/65 mm Hg, pulse rate is 90/min, and respiration rate is 20/min. Abdominal examination reveals tenderness to palpation in the right lower quadrant with no guarding or rebound tenderness. Perianal and rectal examinations are normal.

Colonoscopy discloses evidence of moderately to severely active Crohn disease involving the terminal ileum; the diagnosis is confirmed histologically. Magnetic resonance enterography shows active inflammation involving the distal 20 cm of the ileum without other bowel inflammation or obstruction. There is no evidence of abscess or phlegmon.

Which of the following is the most effective maintenance treatment?

A: Ciprofloxacin and metronidazole
B: Infliximab
C: Mesalamine
D: Prednisone
E: Surgical resection

MKSAP Answer and Critique

The correct answer is B: Infliximab.

The most appropriate treatment is an anti-tumor necrosis factor (anti-TNF) agent such as infliximab. This patient has moderately to severely active Crohn ileitis associated with weight loss and significant symptoms. The SONIC study showed better clinical outcomes when patients with recently diagnosed moderate to severe Crohn disease were treated aggressively with anti-TNF therapy with or without an immunomodulator such as azathioprine or 6-mercaptopurine. Anti-TNF therapy alone was superior to azathioprine monotherapy, and the combination of these two agents resulted in the highest rates of remission and mucosal healing. The decision to use thiopurine or anti-TNF monotherapy versus combination therapy is based on an individual patient’s severity of symptoms and risk factors for developing complications of their disease balanced against the potential side effects of these treatments. An alternative to the immediate use of anti-TNF therapy is the simultaneous initiation of an immunomodulator and corticosteroids with a goal to taper off of corticosteroids within 3 months. If symptoms are not completely controlled after stopping the corticosteroids, then an anti-TNF agent could be added at that time.

Antibiotics are effective in the treatment of abscess and wound infections associated with inflammatory bowel diseases, but their efficacy as primary treatment for Crohn disease and ulcerative colitis is not well established.

Because Crohn disease is a transmural disease, the 5-aminosalicylic acid agents have not proved to be as efficacious as they are in ulcerative colitis. They are often used in the treatment of mild disease but are ineffective in moderate to severe disease.

Corticosteroid therapy on its own may help improve initial symptoms, but the majority of patients will also require maintenance therapy with an immunosuppressant medication to avoid becoming corticosteroid dependent. More aggressive use of anti-TNF agents with an immunomodulator results in higher rates of remission and mucosal healing compared with initial treatment with corticosteroids.

Surgical evaluation would be important if there was concern for perforation, abscess, obstruction, or medically refractory disease, but it would not be the appropriate next step in this patient’s management.

Key Point

• The most effective treatment for patients with recently diagnosed moderately to severely active Crohn disease is anti-tumor necrosis factor therapy with or without an immunomodulator such as azathioprine or 6-mercaptopurine.

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