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Crohn’s disease

Crohn’s disease is a chronic inflammatory disease that mainly affects 
the gastrointestinal tract. It is characterized by transmural inflammation
 ( extending through all layers ) , deep ulceration and fissuring of the mucosa 
and the presence of granulomas .

It may involve any or all parts of the entire GI tract from mouth to 
peri-anal area ( although seen usually in terminal ileum and perianal locations ) interspersed with areas of relatively normal tissue

Rising incidence and prevalence globally Currently no cure for IBD Affects about 1 in 300 people in the Western World At-least 115,000 people in UK with Crohn’s disease ( NICE 2012 ) Can occur at any age but most commonly presents in adolescence and early adulthood 20-30 % cases present in people < 20 yrs Median age of diagnosis is 30 yrs Occurs with equal rate in men and women

Thought to be an immune mediated condition caused by environmental triggering 
events in genetically susceptible people. Chronic inflammation from T-cell activation
 leading to tissue injury is implicated in the pathogenesis Aetiology remains unclear and is widely debated. Possible factors include

risk factors-White ancestry Family history Smoking Infectious gastroenteritis Appendectomy Drugs eg COCP , NSAIDs Not breastfed

When to suspect- Most patients diagnosed in their teens and twenties Consider if
○ unexplained wt loss
○ anaemia
○ family h/o IBD
○ extra-intestinal manifestations

Atleast 50 % patients experience atleast one EIM before diagnosis
 In children –> diarrhoea may not be present in up to 44 % of children with IBD
○ delayed growth and development
 Faecal calprotectin can help differentiate between IBD and irritable bowel syndrome

Presentation- Symptoms can be heterogeneous 

○ diarrhoea ( including nocturnal diarrhoea ) of more than 6 weeks. Caused by
- bacterial overgrowth in obstructed areas
- fistulization
- bile acid malabsorption
- intestinal inflammation with ↓↓ water absorption and ↑↑ secretion of electrolytes Systemic symptoms like malaise , anorexia or fever are common Bowel obstruction due to
acute inflammatory oedema and spasm of the bowel or chronic scarring and stricture Acute terminal ileal CD may be mistaken for acute appendicitis
○ pain often in RLQ ( most common site terminal ileum → ileocolitis ) Abdominal pain and weight loss are seen in about 70 % and 60 % Blood and / or mucus in stool Oral lesions ( apthous ulcers ) Weight loss , faltering growth or delayed puberty in children
 Patients may present with extraintestinal manifestations of CD before intestinal presentations become prominent
 Malabsorption and steatorrhoea

FBC – look for anaemia , raised platelet count , leukocytosis Inflammatory markers – CRP and ESR Urea and Electrolytes LFTs including albumin Iron studies -Ferritin , serum iron , TIBG Serum Vit B12 , Folate and Vitamin D Magnesium , Phosphate Coeliac screen Stool microscopy and culture including C Diff and
Y enterocolitica Faecal calprotectin Plain abdominal radiograph – still essential if intestinal obstruction suspected
as in UC it helps to estimate the extent & severity of Crohn’s colitis
 CT , MRI , US , Barium contrast studies Endoscopic visualization and biopsy Colonoscopy , ileocolonoscopy Small bowel enteroscopy Interventional radiology

Ulcerative colitis Infective colitis Pseudomembranous colitis Macroscopic colitis Intestinal ischaemia Acute appendicitis Diverticulitis Coeliac disease Irritable bowel syndrome Anal fissure Malignancy eg
colorectal cancer
small bowel cancer
lymphoma Endometriosis Laxative abuse

Complications- Psychological Abscesses Intestinal strictures Fistulas Anaemia Malnutrition Colorectal and small bowel cancer

5-Aminosalicylic acid derivative agents Corticosteroids Immunosuppresive agents Monoclonal antibodies Antibiotics Antidiarrhoeal agents Bile acid sequestrants Anticholinergic agents

 BMJ Best Practice Crohn’s disease Crohn’s disease management – NICE guideline October 2012 CKS NHS Crohn’s disease September 2017 The second European evidence-based consensus on the diagnosis and management of Crohn’s disease : Definition and diagnosis European Crohn’s and Colitis Organisation September 2012 Clinical Evidence Handbook Crohn Disease AAFP org Management of Crohn’s Disease in Adults Practice Guidelines The American Journal of Gastroenterology Vol 96 , No 3 , 2001 Crohn’s Disease Medscape Leyla J Ghazi , MD et al Jan 2017 American Gastroenterological Association Institute Technical Review on the Management of Crohn’s Disease After Surgical Resection Gastroenterology 2017 ;152:277-295 Point-of-care and home faecal calprotectin tests for monitoring treatment response in inflammatory bowel disease NICE December 2017 Clinical Review Management of Crohn’s Disease BMJ 1999 ; 319 : 1480 NICE Pathways Crohn’s Disease Overview Faecal calprotectin testing Inflammatory Bowel Disease Toolkit RCGP Crohn’s Colitis UK

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