Crohn’s Disease: Diagnostic Tests

Obligatory medical device diagnostics.

  • Abdominal ultrasonography (ultrasound examination of the abdominal organs).
    • As basic gastroenterological diagnostics (question: thickening of the intestinal wall; fistulas, stenosis, or abscesses; grade of recommendation: A) [characteristic of Crohn’s disease: circumscribed, segmental wall thickening possibly with loss of Haustren (loss of mucosal relief); in the fluorid inflammation stage: Hyperemia (increased accumulation of blood; detection by color-coded Doppler sonography)]
    • Suitable for diagnosis and follow-up
  • Ileocolonoscopy (endoscopy of rectum, colon and a piece of small intestine) with step biopsies (tissue sampling; at least 2 biopsies each from ileum/ small intestine and 5 segments of colon/ large intestine (due todiscontinuous infestation); rectum(rectum should also be biopsied) (grade of recommendation: A) from terminal ileum (last section of small intestine) and each colon segment (for granuloma detection); Attention! In approximately 10% of patients, isolated proximal portions of the small bowel are affected – evidence of characteristic changes in the bowel wall:
    • Skip lesions – edematous distended mucosal islands (cobblestone relief) in the sense of discontinuous inflammation.
    • Small hemorrhages in the mucosa (pinpoint lesions).
    • Deep longitudinal ulcers (longitudinal ulcers).
    • Fistulas
    • Late stage: segmental stenoses (narrowing) and strictures (high-grade narrowing).

    Histological findings (fine tissue findings): transmural inflammation, epithelioid cell granulomas and multinucleated giant cells in about 40% of cases, hyperplasia of lymph nodes; late stage: fibrotic wall thickening (garden hose phenomenon).

  • Esophago-gastro-duodenoscopy (ÖGD; endoscopy of esophagus, stomach, and duodenum) with biopsies is recommended for initial diagnosis and when symptoms of the upper gastrointestinal tract (gastrointestinal tract) occur during the course (grade of recommendation: D)
  • Magnetic resonance imaging of the abdomen (abdominal MRI) as MRI enteroclysm (to visualize the loops of the small intestine) – for the diagnosis of extramural complications such as fistulas and abscesses.

Optional medical device diagnostics – depending on the results of the history, physical examination, laboratory diagnostics and obligatory medical device diagnostics – for differential diagnostic clarification or exclusion of complications.

  • Esophago-gastro-duodenoscopy – should be performed initially, especially in children and adolescents (Grade of Recommendation: B).
  • Double-contrast Sellink/MRI colography – for suspected strictures in endoscopically inaccessible bowel segments [cobblestone relief, filiform stenoses (string sign)/narrowings)]
  • Sellink magnetic resonance imaging (MR-Sellink) [The procedure visualizes inflammation and detects stenoses and fistulas]
  • Advanced small bowel diagnostics with double contrast examination, MRI enteroclysm, MRI enterography.
  • Capsule endoscopy (procedure to visualize the mucosa of the digestive tract (esp. the small intestine) using a swallowable camera capsule) – if small bowel lesions are suspected (grade of recommendation: A); if a high initial suspicion of inflammatory bowel disease (IBD; inflammatory bowel disease, IBD) exists, despite inconspicuous ileocolonoscopy and ÖGD findings and despite inconspicuous MRI examination Contraindications: stenoses in the gastrointestinal tract (narrowings in the gastrointestinal tract); therefore, the procedure should be at the end of the diagnosis.
  • Computed tomography of the abdomen (abdominal CT) should only be used in emergency diagnostics
  • Magnetic resonance imaging (MRI; computer-assisted cross-sectional imaging (using magnetic fields, that is, without X-rays)) – detection of abdominal abscesses.
  • Magnetic resonance cholangiopancreatography (MRCP) – for suspected primary sclerosing cholangitis (PSC).

To determine whether an acute disease flare is present, the CDAI (Crohn’s Disease Activity Index) is determined. If the value is above 150, it is an acute relapse requiring treatment. See Classification for more information.

Carcinoma Prevention

  • Surveillance colonoscopies should be performed [ … ] for extensive colitis [ … ] beginning at 8 years of age and [for findings corresponding to] left-sided or distal ulcerative colitis (CU) beginning at 15 years of age after initial manifestation, once or biennially.(III, ↑ , consensus)
  • If there is concomitant primary sclerosing cholangitis (PSC), surveillance colonoscopies should be performed annually from the time of PSC diagnosis regardless of disease activity and extent of colitis [ … ]. (III, ↑↑ , consensus).
  • After subtotal colectomy (removal of the colon), the same endoscopic surveillance strategies as for colitis [ … ] without resection should be performed by analogy. (III, ↑↑ , strong consensus).
  • The new European Crohn’s and Colitis Organization (ECCO) guidelines recommend endoscopic surveillance in all patients from the eighth year onward, regardless of the pattern of involvement. Only patients with rectal-only involvement no longer need to be monitored. The method of choice is chromoendoscopy with methylene blue or indigo carmine blue and additional targeted biopsies from abnormal areas.