Crohn's disease

Crohn's disease is a chronic inflammatory disease, resulting in swelling and irritation in the digestive tract.

Crohn's disease can affect any part of the digestive tract from the mouth to the anus. The inflammation most commonly affects the distal ileum (small intestine) and the colon (large intestine).

The disease is classified as a type of inflammatory bowel disease (IBD). It usually runs with inflammation, redness, and loss of the normal function of the affected area.

The specific cause of Crohn's disease is unknown, although there seems to be a certain genetic susceptibility.

It is believed that certain infections trigger the immune response (the immune system attacks healthy body tissue by mistake). For that reason, it is considered also an autoimmune disease.

Tobacco increases the risk of suffering from Crohn's disease.

Crohn's disease has an incidence of 5 to 6 cases per 100,000 people per year. Both men and women have an equal chance of being stricken.

Crohn's disease may be diagnosed at any age, although the most common age of diagnosis is between 15 and 35 years old.

The most common symptoms are:

• Chronic diarrhea
• Abdominal pain
• Fever
• Weight loss
• A feeling of fullness in the right lower quadrant of the abdomen
• Fatigue

In many patients, the first clinical sign is an "acute abdomen" that may be similar to appendicitis or bowel obstruction. Both possibilities should be considered.

The symptoms of Crohn's disease can worsen if there is a bowel obstruction, an abscess formation, or a fistula formation.

In addition to the intestinal manifestations of the disease, some complications or related diseases may also occur, mainly extraintestinal. The most common ones are:

• Disease dependent: Peripheral arthritis, episcleritis, aphthous stomatitis, erythema nodosum, and pyoderma gangrenosum.
• Disorders associated with inflammatory bowel disease, but independent of Crohn's disease: Ankylosing spondylitis, sacroiliitis, uveitis, and primary sclerosing cholangitis.
• Complications directly related to the disease: Changes in uric acid metabolism, disorders of urinary dilution and urine alkalinization, and excess absorption of oxalate.

The most common tests and procedures used to diagnose the disease are:

• Clinical: Symptoms and signs suggestive of the disease.
• Blood test: They are non-specific and may include anemia, leukocytosis, hypoalbuminemia, and increased levels of acute phase reactants (APR) such as an elevation of ESR, C-reactive protein, and/or orosomucoids.
• X-ray and endoscopy: X-ray or an endoscopy of the digestive tract may confirm the diagnosis. The barium enema may show barium reflux into the terminal ileum with irregular nodular wall thickening of the wall, and a narrowing of the ileum lumen. In general, a bowel transit study examination with X-rays focused on the terminal ileum may reveal the nature and extent of the lesion. In a gastroduodenal transit study, without the study of the entire small bowel, the diagnosis most times is unnoticed.
• Colonoscopy and biopsy: In case of doubt, colonoscopy and biopsy can help to confirm the diagnosis of Crohn's colitis and, in many cases, they allow the direct visualization and biopsy of the terminal ileum.
• CT (Computed Tomography): Although CT is useful to characterize anatomopathological alterations of the intestinal wall and identify a possible abscess, is not necessary for the initial diagnosis.

There is no cure for Crohn's disease, but there are different palliative therapy.

• To relieve cramps and diarrhea: Anticholinergics and diphenoxylate may be administered.
• To prevent anal itching: Some fiber preparations (e.g., methylcellulose or psyllium) may help prevent anal itching by increasing the stool consistency.
• To reduce the activity of the disease: Broad-spectrum antibiotics against gram-negative and anaerobic flora may be useful to reduce disease activity in some patients (metronidazole).
• To control the inflammation: A chronic treatment with sulfasalazine is useful to control low-grade inflammation, particularly in the colon, but is less effective in severe acute exacerbations. It is not usually adequate to prevent postoperative recurrences (relapses). There are novel sulfasalazine analogs that provide higher concentrations of 5-aminosalicylic acid (5-ASA), which is the active component, and a little concentration of sulfapyridine, which is the molecular component responsible for most of the adverse effects of sulfasalazine.
• When the colon is affected: Immunosuppressive drugs may be used. Antimetabolites, azathioprine, and 6-mercaptopurine are effective in Crohn's disease, especially when the colon is affected.
• For moderate and severe inflammation: Over the last few years, biologic agents such as anti-TNF agents (Infliximab, Vedolizumab, Adalimumab, Golimumab, Certolizumab, Ustekinumab, etc.) are being used successfully. In Crohn's disease, they help reduce inflammation and pain.

Surgery is usually necessary to repair a bowel obstruction that does not resolve on its own, to remove an abscess, or to repair a fistula.

Crohn's disease is a lifelong chronic illness.

The severity of the disease can vary with symptoms-free periods when the disease is not active. However, the complications tend to increase over time. It is estimated that 60% of those who suffer from Crohn's disease will require surgery.