Investigations

Investigations carried out in primary care for suspected inflammatory bowel disease include:

• full blood count
• C reactive protein and ESR
• urea and electrolytes
• liver function tests
• stool culture and microscopy – to exclude infectious causes (1,2)

Investigations in Crohn's disease are aimed at:

• making the diagnosis
• monitoring disease activity.

To this end, a variety of modalities may be used:

• blood tests
• imaging
• endoscopy: both upper and lower GI endoscopy.
• histology: full thickness inflammation, non-caseating granulomata, fissuring, ulceration, erosions.

Notes (3):

• endoscopy has always been the gold standard for assessing mucosal activity in Crohn's disease, but its use is limited by its invasiveness and its inability to examine the small intestine, proximal to the terminal ileum
  • enteroscopy and the less invasive small bowel capsule endoscopy enable the small bowel to be explored
• in addition to ultrasound, magnetic resonance and computed tomography are tools for monitoring and assessing inflammatory activity in the mucosa and the transmucosal extent of the disease, and for excluding extra-intestinal complications
• in addition to markers such as CRP, faecal biomarkers such as calprotectin and lactoferrin, are useful to identify the inflammatory burden of the disease and to identify patients requiring further investigations
  
  

Reference:

• (1) Cummings JR, Keshav S, Travis SP. Medical management of Crohn's disease. BMJ. 2008;336(7652):1062-6
• (2) British Society of Paediatrics Gastroenterology Hepatology and Nutrition (BSPGHAN) 2008. Guidelines for the Management of Inflammatory Bowel Disease (IBD) in Children in the United Kingdom
• (3) D'Inca R, Caccaro R.Measuring disease activity in Crohn's disease: what is currently available to the clinician. Clin Exp Gastroenterol. 2014 May 20;7:151-61.