Crohn's disease is a chronic inflammatory condition of the gastrointestinal tract with variable symptoms. There is no single test to diagnose it, so a combination of examinations is used, including endoscopy, imaging, blood tests, and biopsy. Disease extent and activity are classified using several indices, though they do not perfectly correlate with objective inflammation measures. Endoscopy, cross-sectional imaging like MRI or CT, and small bowel ultrasound are used to determine disease location and activity, with MRI found to be the most sensitive in detecting small bowel involvement. Various endoscopic and radiological scoring systems exist to measure activity and assess treatment response.

1. CROHN’S DISEASE
BRITISH SOCIETY OF GASTROENTEROLOGY
PREPARED BY
ELSAYED KHAMIS ELRASHIDY
MASTER DEGREE OF INTERNAL MEDICINE

2. • crohn’s disease is a complex chronic inflammatory gastrointestinal condition with variable
age of onset, disease location and behavior.
• There is no single unifying definition of Crohn’s disease and a combination of investigative
modalities is often needed to confirm the diagnosis.
• Factors include an appropriate clinical history and examination, ileocolonoscopy, small
bowel imaging, blood tests and histology.

3. PHENOTYPIC CLASSIFICATION
• Montreal and Paris define disease extent according to endoscopic or macroscopic
features.

5. CLINICAL AND ENDOSCOPIC DISEASE ACTIVITY
• The Crohn’s disease activity index (CDAI)
• In clinical practice:
• difficult to calculate,
• requires diary data from patients,
• is weighted towards diarrhea (which is often caused by factors other than inflammation),
• is not usable in patients with stomas and is not validated for use after surgery

7. • Harvey Bradshaw Index (HBI)
• is both simple to calculate and measure,
• and less susceptible to confounding factors relying on clinical parameters only,
• yet is heavily weighted by diarrhoea.

9. • It should be noted that these measures don't correlate well with objective markers of
inflammation in Crohn’s disease, as subjective factors including psychological status
impact significantly on patient-reported well-being
• these measures are thus complementary to objective measures of disease activity
obtained at endoscopy, imaging and surrogate measures including faecal calprotectin.

10. ENDOSCOPIC SCORING SYSTEMS
• the two most commonly used are the Crohn’s Disease Endoscopic Index of Severity
(CDEIS) and the Simplified Endoscopic activity Score for Crohn’s disease (SES-CD).
• Both are used to assess for complete mucosal healing as an end-point in clinical trials.

13. VALIDATED MRI ACTIVITY SCORES ARE INCREASINGLY
USED AS ADJUNCT END-POINTS IN CLINICALTRIALS .

14. • The Rutgeerts score is used specifically to assess recurrent disease in the neo-terminal ileum
after surgery

15. DIAGNOSTICTESTS
• Ileocolonoscopy with biopsy is established as the first-line investigation for suspected
Crohn’s disease.
• Ileoscopy with biopsy histology is superior in establishing the diagnosis of mild ileal
Crohn’s disease, however, intubation of the terminal ileum may not always be possible,
and up to 20% of patients have isolated proximal small bowel disease beyond the reach of
even complete ileocolonoscopy.
• Ileoscopy and radiological imaging are complementary in diagnosis of ileal Crohn’s
disease.

17. • If there is vomiting,dyspepsia or other upper GI symptoms then upper GI endoscopy is
indicated, but not routinely in adults with suspected or proven Crohn’s disease

18. • Dedicated small bowel imaging should be performed to complement ileocolonoscopy in
all patients with suspected Crohn’s disease and those with an unclassified colitis at
ileocolonoscopy.

19. CROSS-SECTIONAL IMAGING: CT, MR AND SMALL
BOWEL ULTRASOUND
• Several meta-analyses show no consistent difference in accuracy for Crohn’s disease
diagnosis between CT enterography (CTE), MR enterography (MRE) or small bowel
ultrasound (SBUS).

20. • However, a recent UK multicentre trial of 284 newly diagnosed or suspected relapse
Crohn’s disease patients showed that MRE had greater sensitivity for small bowel disease
extent (presence and location) compared with SBUS (80% vs 70% respectively).
• MRE also had greater specificity than SBUS (95% vs 81% respectively), although SBUS
had superior sensitivity to MRE for colonic disease presence in newly diagnosed patients
(67% vs 47% respectively).

21. DETECTION OF ACTIVE DISEASE
• Accuracy for detecting patients with active disease is generally reported to be over 85%.
although the data supporting SBUS is currently less consistent than for MRE and CT
enterography, and multicenter trial data suggest MRE is significantly more sensitive than
SBUS for detecting active small bowel disease (96% vs 90% respectively).
• Radiological signs of disease activity include increases in bowel wall thickness and
vascularity, contrast enhancement,T2 and diffusion weighted imaging signal (for MRE), and
identification of ulceration and acute extraluminal complications.

22. INVESTIGATION OF STRICTURES
• Up to 3.5% of Crohn’s disease strictures may be complicated by dysplasia or malignancy
so endoscopic biopsy of accessible strictures should be performed to achieve a
pathological diagnosis.

23. RADIATION EXPOSURE
increase their lifetime risk of cancer
factors associated with excessive diagnostic radiation exposure .
• age under 17 at diagnosis.
• upper gastrointestinal disease location.
• penetrating disease.
• need for intravenous corticosteroids
• and more than one Crohn’s disease surgical operation.

24. CAPSULE ENDOSCOPY
• high resolution endoluminal images of the small bowel
• less invasive than conventional endoscopic techniques
• usually well tolerated by patients

25. • use of capsule endoscopy should be restricted to those with a high clinical suspicion of
Crohn’s disease (suggestive clinical picture and raised faecal calprotectin) and abstinence
from NSAID ingestion for at least 1month, where cross-sectional imaging has been
normal or equivocal.

28. BALLOON-ASSISTED ENTEROSCOPY
• costly, invasive, requiring deep sedation or
general anaesthesia, and not without risk
• reserved for patients with high clinical
suspicion of Crohn’s disease despite
negative ileocolonoscopy
• role in established Crohn’s disease where
therapeutic intervention, such as stricture
dilatation, is needed.

29. Thank you