General: Crohns Disease

Question 1

Outline the pathophysiology of crohns disease

Answer 1

CD can affect any part of the GI tract (mouth to anus)

Commonly targets the distal ileum or proximal colon

Transmural = deep ulcers and fissures (cobblestone)

Skip lesions

Microscopic = non-caseating granulomatous inflam

Question 2

What are the causes of crohns?

Answer 2

Unknown

Smoking increases risk

Question 3

How does crohns present?

Answer 3

Episodic = acute attacks before entering remission

Abdo pain = may be colicky, vary in site

Diarrhoea = often chronic and bloody

Oral ulcers

Perianal disease

Systemic = malaise, anorexia, low-grade fever

Question 4

What investigations should be performed when crohns is suspected?

Answer 4

Bloods = FBC (Hb, ESR, MCV), albumin, CRP, WBC, b12, +ve ASCA -ve pANCA

AXR = exclude toxic megacolon, obstruction

Faecal calprotectin = NICE guidelines in pts with lower GI symptoms

Stool sample = microscopy and culture

Colonoscopy with biopsy (not in acute cases due to risk of rupture) = cobblestoning

Barium swallow

CT scan = in severe crohns, obstruction, perforation, fistulae

Pelvic MRI = pts with perianal disease

Question 5

What are the extra-intestinal features of crohns

Answer 5

MSK = Enteropathic arthritis (typically affecting sacroiliac and other large joints) or nail clubbing, metabolic bone disease (sec to malabsorption)

Skin = erythema nodosum (shins), pyoderma gangrenosum – erythematous papules/pustules that develop into deep ulcers

Eyes = Episcleritis, anterior uvetitis, or iritis

Hepatobiliary = Primary sclerosing cholangitis, cholangiocarcinoma, gallstones

Renal = renal stones

Question 6

How is crohns managed?

Answer 6

Acute attack = fluid resuscitation, nutritional support, prophylactic heparin, prednisolone

Severe = hydrocortisone, metronidazole (perianal disease, infection), consider need for blood, infliximab

Immunosuppression = mesalazine or azathioprine

Infliximab, rituximab (TNF alpha inhibitors)

Smoking cessation

IBD-nurse specialists and patient support groups

Surgical = ileocaecal resection

Question 7

What are the possible complications of crohns?

Answer 7

Stricture formation = resulting in bowel obstruction and perforation

Fistula = enterovesical, enterocutaneous, or rectovaginal fistula

Perianal abscesses or fistulae

GI malignancy

Malabsorption = growth delay in children

Osteoporosis = sec to malabsorption or long-term steroid use

Increased risk of gallstones = due to reduced reabsorption of bile salts at inflamed terminal ileum

Increased risk of renal stones = due to malabsorption of fats which cause calcium to remain in the lumen

Question 8

What factors increase the risk of developing IBD?

Answer 8

FH = 20% have first degree relative affected

Smoking (protective against UC, risk for crohns)

White European descent

Appendicectomy

Question 9

What are the indications for surgery in inflammatory bowel disease?

Answer 9

Those with failed medical management

Strictures

Fistulas

Growth impairment in younger patients

Toxic megacolon (US)