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home - IBD - IBD Diagnosis - Crohns Diagnosis Written by Dr Sebastian Zeki

Knows the differential diagnosis of IBD including bacterial and
amoebic infection, CMV, IBS, drug induced injury (NSAIDs)
microscopic colitis and vasculitis.

Uses appropriate investigations including blood tests, stool cultures
and intestinal imaging modalities.

Exhibits sympathy to patient, orders appropriate tests in a timely
manner, and involves members of the multidisciplinary team including
IBD nurse and surgeon as appropriate.


Knows the major differential diagnoses of IBD including infection –
viral bacterial and amoebic vasculitis ischaemia Behcet’s disease
irritable bowel syndrome etc

Knows the appropriate investigations to distinguish the above and
their limitations

Knows the differential when patient with know IBD presents with
symptoms including – active IBD bacterial overgrowth bile salt
malabsorption obstruction

Able to identify appropriate investigations to make a positive
diagnosis of IBD or to exclude it

Able to interpret the results of the above investigations
Outline to patients the possible causes of their symptoms
Explains and initiates the appropriate sequence of investigations
Can explain to patients the outcome of the investigations and their


Methods GMP
Understands the appropriate investigations for assessing disease
activity and extent including:
• inflammatory markers in blood (ESR, CRP, highly sensitive
CRP) and stool (faecal calprotectin, lactoferrin etc)
and imaging techniques, including
• upper and lower GI endoscopy, CT and MRI scanning,
capsule endoscopy, enteroscopy and barium imaging
SCE, mini-CEX, CbD 1
Understands the circumstances in which disease activity and extent
should be reassessed, and when complications should be suspected
(e.g. perforation, abscess formation, fistulisation)
SCE, CbD 1 Gastroenterology 2009 Page 106 of 155
Able to make a clinical assessment of a patient and determine the
requirement for further assessment using inflammatory markers and
SCE, mini-CEX, CbD 1
Can suspect the presence of complications appropriately and take
appropriate action in terms of investigation and management
SCE, mini-CEX, CbD 1,2
Explains the extent and activity of disease to patients, and to explain
their implications
mini-CEX, MSF 1,2,3,4,
Can liaise with IBD nurses, radiologists and other healthcare
professionals to ensure timely investigation and appropriate
management of IBD and its complications

Crohns Diagnosis

The role of OGD and biopsy in a patient with CD CD involving the upper GI tract usually has small or large bowel involvement.Gastric biopsies may be useful when a patient has colitis unclassified, as focal active gastritis in the absence of ulcer-tion may be a feature of CD. Differentiation between inflammatory and fibrostenotic strictures The presence of ulceration indi-cates active inflammation.Contrast enhanced Doppler US may be valuable in determining disease activity within strictures.Both CT and MRI illustrate mural changes with disease activity, but MRI is more sensitive. Extramural complications diagnosisUSS is good for the detection of fistulas (Se 87%) and abscesses (100%).CT and MRI are very se for fistulas, abscesses, and phlegmons.MRI has a sensitivity of 83% for fistulas and 100% for abscesses.MRI enteroclysis is good and probably better than US for detecting extramural complica-tions of CD, but fluoroscopic studies are poor value. Anatomical criteria of severity are defined as 1)deep ulcerations eroding the muscle layer, 2)or mucosal detachments or ulcerations limited to the submucosa but extending to more than one third of a defined colonic segment (right, transverse, left colon) The most useful endoscopic features of CD are: discontinuous involvementanal lesions cobble stoning Nonintubation examinations-SBESe of 93% and a sp of 92% to exclude small bowel diseaseSBFT better than SBE for detecting mucosal disease, fistulas, or gastroduodenal involvement; not good for strictures-USSe is 90% Misses lesions predominantly in the upper GI tract or rectosigmoidThe role of colour, power or contrast enhanced Doppler being evalu-atedIntubation examinations-Helical CT-enteroclysis or CT enterography-not bad-MRE-Superior sensitivity and specificity (95% and 93%) compared with SBE (85% and 77%) for primary diagnosis of CD but more invasive.-Leucocyte scintigraphy- Lacks specificity and no good if patient on steroids DiagnosisPatients need full colonoscopic series from affected and unaffected areas.Take neoterminal ileum bx for suspected post-sugical recurrence.For ileal pouch-anal anastomosis, biopsies of the afferent limb are indicated when CD is suspected.Multiple biopsies are indicated when the patient is investigated during screening for dysplasia (= intraepithelial neoplasia). Crohn’s Diagnosis Procedures recommended for estab-lishing the extent of stricturing CD :AXR which is as good as CT in showing stricture;CT can also tell the cause.Enteroclysis examination- this best distends the bowel to reveal extent and number of strictures.CT colonography (CTC) can show the mucosal pattern and show colitis proximal to a stricture, but may not identify all stric-tures seen on colonoscopy. Adantages of MRI vs CT include-Superior tissue contrast-Absence of radiation exposure-Capability of selecting cross sectional planes (transverse, coronal, sagittal)-Higher sensitivity for intestinal and extraintestinal changes in CD. Intubation examinationNumber of biopsies MRI enteroclysis as good as SBEEnteroclysis good for irreversible stenosis vs functional spasmIf colonoscopy is incomplete because of stricture, then double, or even single contrast barium enema are usually proce-dures of first choice Role of wireless capsule endoscopy (WCE) in suspected or proven CD More sensitive procedure than SBFT and CT-enteroclysis in diagnosing Crohn’s but cant get biopsies.Can’t do if GI obstruction/strictures/fistulas/pacemakers or other implanted electric devices, and swallowing disorders Written by Dr Sebastian Zeki

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