Crohn's disease: causes, symptoms and treatment

Marina Virko
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Johannes Grossmann

Definition and causes

Crohn's disease is a chronic condition of the gastrointestinal tract, characterized by the development of an inflammatory process in one or the other region, with local or systemic complications. The exact causes are unknown, but genetic predisposition and immune system disorders are considered as likely reasons. Appendectomy is seen as one of the risk factors.

Disease signs

Crohn's disease involves the mucosa of any part of the gastrointestinal tract. In 65-70% of cases, the ileum and ileocecal valve (the area where the small intestine passes into the large intestine) are affected. Segmental colitis and rectal involvement occur in 20% of cases. In one in five cases, the entire colon is affected.

Clinical pattern of the disease

The signs of Crohn's disease depend on the localisation of the inflammatory process. Characteristic are:

  • diarrhoea;
  • abdominal cramps that intensify after meals;
  • pain in various locations;
  • severe flatulence.

Latent bleeding may develop, indicated by anemia. These patients often refuse to eat, which results in severe weight loss.

Inflammation progress and the involvement of nearby tissues lead to the formation of fistulas, i.e., abnormal connections between the cavities. This leads to the development of an abscess with fever and a high risk of sepsis (blood poisoning).

Extraintestinal symptoms occur in one in five cases and include inflammation of the mucosa of the eyes, bile ducts, liver, joints and skin rashes.


The first step in making a diagnosis of Crohn's disease is a thorough case history and physical examination. The physician palpates the abdomen to detect resistance or tenderness on pressure due to inflammation. A stool sample is examined for calprotectin, and blood is analyzed for markers of inflammation. The blood test also provides information about possible nutrient deficiencies. The next stage is an endoscopic exam of the intestine (colonoscopy). It makes it possible to conduct a visual inspection of the intestine from the inside and take samples of its tissues for further study in the laboratory. With the help of lower abdomen ultrasound, the doctor determines whether the intestinal walls are thickened. A gastroscopy or magnetic resonance imaging may be needed for a more accurate diagnosis of Crohn's disease.

Differential diagnosis

In patients with Crohn's disease, it is important to rule out other conditions, such as irritable bowel syndrome, infectious lesions of the digestive tract mucosa, and ulcerative colitis. Pain in the lower abdomen may indicate appendicitis and pseudotuberculosis. Granulomas may form on the intestinal mucosa in sarcoidosis. Stenosis is characteristic of bowel cancer and lymphoma.

Treatment of Crohn’s disease

If there are no complications, the condition can be treated with drugs in combination with a diet. Loperamide and antispasmodic drugs can help with diarrhea and painful cramps. Crohn's disease patients should take these medicines before meals to increase their effect. A low-fiber diet is essential.

Aminosalicylates are prescribed to fight inflammation, such as mesalamine, balsalazid, olsalazine.

Corticosteroids are equally effective. They are preferably administered as intravenous injections, to avoid the stomach. They can relieve such symptoms as abdominal pain, cramps, diarrhea and fever in the acute period. The drugs are usually used in high doses at the beginning, and only when the condition has stabilized is the dosage reduced, or the treatment is stopped.

Immunosuppressants are also used. Patients in whom the above-mentioned treatment is unsuccessful may get azathioprine and mercaptopurine. They suppress the immune system, allow the dosage of corticosteroids to be reduced, and increase the duration of remission, but can cause side effects.

In case of corticosteroid intolerance, methotrexalate is used, but it is contraindicated during pregnancy.

For fistulas high-dose cyclosporine is administered. It has a high risk of side-effects and should therefore be used in short courses. Tacrolimus is also highly effective.

Monoclonal antibodies have successfully been used in the recent years in patients with moderate to severe disease. In particular, infliximab relieves the symptoms of the disease when other measures fail to work. Adalimumab, certolizumab are similarly effective.

Antibiotics may also be required, such as metronidazole, ciprofloxacin, levofloxacin, or the non-resorbable antibiotic rifaximin for Crohn's disease is in the active phase.

In severe cases hospital stay and parenteral nutrition may become necessary. Blood transfusion is indicated for bleeding.

If there is no effect, or if complications develop, physicians resort to surgery. Removing the affected part of the intestine helps to alleviate the condition, but does not get rid of it. There is always a risk that symptoms of the disease will develop with other parts of the body being affected. Often, the first operation is followed by a second or third one after some time. Therefore, doctors weigh the arguments for and against such surgery very carefully.

Prognosis and prevention

Crohn's disease is one of those chronic diseases that cannot yet be entirely cured. However, timely and proper therapy can ensure a good life quality and normal life expectancy.

There is no general prognosis for all patients, since the course of the disease varies greatly. Preventive measures are aimed primarily at the timely detection of relapses and complications. This requires regular examinations to monitor blood counts and internal organ function. It should be noted, however, that the risk of developing intestinal cancer in people with Crohn's disease is higher than in those who are not affected by this condition.


  1. How Crohn's Disease Is Treated. By Amber J. Tresca Updated on December 23, 2021. 
  2. Crohn's disease.
  3. Crohn's disease: a population-based study of surgery in the age of biological therapy. 
  4. Crohn's Disease: Diagnosis and Management. 
  5. Image source: Free Stock photos by Vecteezy

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Галина Ильченко

Если у тебя болезнь Крона, ты не можешь бездумно что-нибудь съесть. Я точно знаю, что именно мне кушать нельзя: очень соленое или сладкое, очень холодное или горячее, очень острое или жирное, а также жареное или трудное для переваривания, например, цельнозерновые продукты. После тушёного, пареного проблем обычно нет. Если пробую что-то новое, то в минимальных количествах, так и определяю, что подходит, а что нет.

Please avoid self-diagnosis and self-medication!

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