Crohn's disease

Overview

Crohn's disease is a form of inflammatory bowel disease. Unlike ulcerative colitis, it can affect any part of the digestive tract — from the mouth to the anus — most often the ileum (the end of the small intestine) and the colon. The inflammation can involve the whole thickness of the bowel wall and appears in patchy areas, with healthy segments in between.

The disease goes through periods of activity and quiet. It is not contagious.

Symptoms

• prolonged diarrhea
• abdominal pain, often in the lower right part
• fatigue, anemia, weight loss, sometimes fever
• mouth ulcers
• fistulas or abscesses around the anus
• inflammation of the eyes, skin or joints

Causes

The disease arises from the interaction of genetics, the immune system, the gut microbiome and environmental factors. Smoking increases the risk and worsens the course — quitting smoking is one of the most important steps of treatment. Stress can influence symptoms, but does not cause the disease.

Complications

Strictures of the bowel, fistulas, abscesses and malnutrition. These are the reason the disease must be followed even when symptoms are mild.

Diagnosis

• Blood and stool tests, including fecal calprotectin.
• Ileocolonoscopy with biopsy — examines the colon and the end of the small intestine.
• Small bowel imaging — enterography with magnetic resonance (MR) or with CT; in selected cases bowel ultrasound or capsule endoscopy (after the risk of obstruction has been ruled out).

The diagnosis relies on the combination of these data; no single test is enough.

Treatment

The goals are: controlling inflammation, remission without long-term corticosteroids and preventing complications.

• Corticosteroids — for short periods of activity; they are not maintenance treatment.
• Immunomodulators (e.g. azathioprine, methotrexate).
• Biologic drugs and targeted small-molecule drugs — for moderate and severe forms.

Oral mesalamine is usually not recommended for Crohn's disease, unlike ulcerative colitis.

Surgery is needed for obstructions, abscesses, fistulas or disease that is not controlled with medicines. It treats the complication, but does not permanently cure the disease; after surgery, follow-up is planned for early detection of recurrence.

Diet

Diet is adapted according to tolerance and, if there are strictures, with less coarse fiber. Do not eliminate whole food groups without advice — this can cause malnutrition. Iron, vitamin B12, vitamin D and other nutrients are checked regularly.