Digestive Disorders > IBD > Crohn's Disease

Crohn's disease diagnosis: The complete guide

Dr. med. Andre Sommer

Dr. med. Andre Sommer

The diagnosis of Crohn's disease is often difficult and lengthy, and is often made by accident. The symptoms are not very specific, so Crohn's disease can easily be mistaken for irritable bowel syndrome or appendicitis.

Those affected have a high level of suffering, especially if the disease is initially misdiagnosed. The main symptoms of abdominal pain and diarrhea increase the level of suffering and severely restrict the sufferers in their everyday life. To make the correct diagnosis, ultrasound, blood tests, and a colonoscopy (among other tests) are carried out.

What is Crohn's disease?

Crohn's disease (Enterocolitis Regionalis), along with ulcerative colitis, is a chronic inflammatory bowel disease. Unlike ulcerative colitis, Crohn's disease can occur throughout the gastrointestinal tract, from the esophagus to the anus, but most often it affects the end of the small intestine (ileum) and the beginning of the large intestine (colon). The entire intestinal wall is affected, including deeper layers.

The disease occurs in flare-ups. One important risk factor is smoking. Crohn's disease most often occurs for the first time between the ages of 15 and 35.

What are the first signs of the disease?

The first signs of Crohn's disease are severe, sometimes cramp-like abdominal pain, which is particularly often located in the right lower abdomen. The right lower abdomen includes the section of the intestine that is most often affected. However, the pain can occur all over the abdomen. In addition, there may be diarrhea, which is mostly without blood admixtures. Diarrhea or particularly soft bowel movements that occur more than three times a day and also at night should definitely be clarified. Another symptom can be nausea.

There may also be a slight increase in temperature. In some cases, the symptoms include constipation and a bloated stomach. Many patients also notice weight loss and loss of appetite.

In children, the disease manifests itself in particular through a growth delay. This can include inflammatory skin changes in the subcutaneous fatty tissue on the legs (erythema nodosum). The eyes or joints can also be inflamed.

In addition, fistulas and abscesses can occur in the anal area. Such anal fistulas are often the first sign of Crohn's disease.

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How is Crohn's disease diagnosed?

Symptoms Ultrasound Blood test Stool test Colonoscopy (with tissue sample)
Stomach pain Thickened intestinal wall Increased white blood cells Increased calprotectin Ulcerations
Diarrhea Increased C-reactive protein Increased lactoferrin Stenoses
Nausea Increased blood

sedimentation rate

Examination for infections (suspicion of Clostridium difficile) Tissue changes

1. Consultation

The examining doctor, usually an internist who specializes in gastrointestinal diseases (gastroenterologist), first talks to the patient about the medical history in order to inquire about possible symptoms and symptoms and to differentiate other diseases. Crohn's disease can easily be mistaken for appendicitis, but appendicitis begins more quickly. If the doctor suspects Crohn's disease, they will carry out further diagnostics.

2. Physical examination

When palpating the abdomen, painful hardening of the right lower abdomen is often noticeable. This suggests that the intestinal area in this area is affected by the inflammation. With Crohn's disease, the intestine in the right lower abdomen is most often affected. Appendicitis is also manifested with pain when palpating the right lower abdomen.

3. Ultrasound

The doctor can do an ultrasound of the abdomen. By doing this, they can identify inflamed sections of the intestine. What is striking here is an intestinal wall thickened by the inflammation. Abscesses and fistulas (connection between two organs or one organ with the surface of the body that does not exist naturally) can also be identified in this way.

4. Laboratory diagnostics

The attending doctor examines the patient's blood and stool.

4. 1 Blood test

Nonspecific inflammation markers are often found in the blood. These include an increase in white blood cells (leukocytosis), increased C-reactive protein, fibrinogen and an increased value of the sedimentation rate. Anemia can result from bleeding in the gastrointestinal tract and poorer iron or vitamin intake.

4.1 Stool test

In the stool sample, increased calprotectin values indicate inflammation of the mucosa. The doctor also examines the patient's stool for bacteria to rule out the cause of the discomfort. Even if the blood values are normal, the intestine can still be inflamed. If the doctor continues to suspect that the patient may have Crohn's disease, they will have a colonoscopy for further clarification.

5. Colonoscopy

It is important for a colonoscopy that every section of the gastrointestinal tract is examined, since inflamed and non-inflamed sections of the bowel alternate in Crohn's disease. The doctor may see ulcers, narrowing and small bleeding in inflamed sections. The doctor takes tissue samples and then has them examined for suspicion (step biopsy).

With Crohn's disease, the pathologist often finds specific tissue changes (granulomas, giant cells). Gastroscopy is also important to clarify whether upper sections of the digestive tract are affected. For example, these are often affected in children.

6. MRI

With an MRI contrast agent, a thickening of the intestinal wall and enlarged lymph nodes in the gastrointestinal tract can be depicted. Possible fistulas can also be diagnosed this way.

Diagnosis in children

The upper part of the digestive tract, i.e. the stomach and esophagus, is more often affected in children. Other, rather nonspecific complaints are loss of appetite and abdominal pain. There is often mild diarrhea and weight loss. Due to the poor absorption capacity of the intestine due to the inflammation, the affected children are often small and enter puberty later (growth retardation).

Episodic occurrence

Since the disease occurs in flare-ups, there are times when the patient is symptom-free (remission). During this time, the patients have no abdominal pain, diarrhea or other complaints. The inflammation values also normalize. The remission can also be determined using ultrasound or MRI. The duration of the remission varies from patient to patient. The doctor tries to enable and extend this with medication. If the flare-up lasts more than 6 months, the disease is referred to as chronic.

What happens after a diagnosis?

After a diagnosis of Crohn’s disease, the doctor classifies the patient according to the Montreal classification in order to assess the prognosis and course of the disease. They take into account the age of the onset of the disease, the location of the inflammation in the gastrointestinal tract and the biological behavior (e.g. scarring or fistula formation).

Together with the patient, a customized therapy plan is then drawn up, which includes a change in diet and medication, possibly even surgical treatment. The aim is to achieve remission of the disease.

Herold, Gerd: Innere Medizin, 2017

Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften. AWMF – Leitlinien. Langfassung der Leitlinie. Diagnostik und Therapie des M. Crohn. Register number 021-004 downloaded online on 4/3/2018 from http://www.awmf.org/uploads/txszleitlinien/021-004lS3MorbusCrohnDiagnostikTherapie_2014-09.pdf

Dr. med. Andre Sommer

Dr. med. Andre Sommer

I’m André, a medical doctor from Berlin. Together with a team of medical doctors, nutritionists and data scientists we empower people to understand digestive issues with our app Cara Care.

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