Anorexia in Crohn's disease

Question 1

Definition of anorexia

Answer 1

loss of appetite, due to acute/chronic disease, drugs or anorexia nervosa

Question 2

Anorexia nervosa: definition, age of onset, comorbidities/mortality

Answer 2

• definition: extreme weight loss, body dysmorphia, fear of weight gain
• usually occurs age 15-16 years or early adult onset
• high levels of mortality (5%)
• Anorexia and Crohn’s disease can co-exist

Question 3

Crohn’s disease: definition, epidemiology, aetiology

Answer 3

• definition: trans-mural granulomatous inflammation of the GI tract (can occur in skip lesions from mouth to anus). Severity increases over time, and severely impacts QoL
• epidemiology: incidence is 7 in 100,000. Prevalence is 100 per 100,000. Higher in caucasian, Western cultures and in women (1.2:1)
• aetiology: likely to be a combination of genetic susceptibility (50% concordance in MZ, only explains 20-30% of disease though, 241 genes found implicated so unlikely to be Mendelian), environment (smoking, oral contraceptive pill, NSAIDs, bacterial infection, diet as EN improves symptoms), immune response (problems with intestinal barrier function, abhorrent activity with Th1, Th17, macrophages, neutrophils, NK cells)

Question 4

Clinical features of Crohn’s

Answer 4

• inflammation doesn’t correlate with disease severity
• 15% are asymptomatic
• in small bowel symptoms are: weight loss, pain
• in colon: usually diarrhoea and urgency
• malaise, fever and lethargy
• extra-intestinal manifestations: joints (arthritis), eyes (conjunctivitis), skin (erythema nodosum, pyoderma gangrenosum), kidneys (stones, amyloidosis), liver (hepatitis), finger clubbing, oral ulcers

Question 5

Diagnosis of Crohn’s disease

Answer 5

• bloods: Fe/B12 deficiency, anaemia, LFTs, increased CRP/decreased albumin
• stool cultures: faecal calprotectin (surrogate marker of inflammation as a neutrophil cytosolic protein)
• imaging: barium imaging, CT/MRI/ultrasound. Can be used to see obstruction
• colonoscopy: invasive but essential for macro and microscopic diagnosis (can see ‘cobble-stoning’ granulomas and deep ulceration

Question 6

Intestinal complications of Crohn’s

Answer 6

• obstruction due to inflammation/swelling, strictures (need surgical intervention), adhesions (due to previous surgery)
• fistulae: typically after surgery due to transmural inflammation, structures are connected which shouldn’t be (i.e. bowels/bladder or skin and perianal fistulae most common and causes infection and abscesses)
• malnutrition: decreased intake due to anorexia, malabsorption, protein losses, increased metabolic demands of being sick
• short bowel syndrome: entero-enteric or enterocutaneous fistulae leads to malabsorption energy, macros and electrolytes
• cancer: high risk of colorectal cancer (same as UC) 10 years after diagnosis colonoscopy is done to check for dysplasia and every 5 years after that. Small intestine and anal cancers less likely

Question 7

Management of Crohn’s disease

Answer 7

• Aims: to induce remission and to manage comorbidities
• depends on site and severity
• MDT: needs psychosocial and dietary support as well as pharmacological
• Pharmacological: Steroids used for acute flares, azathioprine/MTX used for maintenance, mainstay is biologics (anti-TNFs- infliximab, adalimumab) (anti-integrin receptor- vedolizumab) (anti-IL12 + IL23- ustekinumab)
• surgery: 70-80% of patients with Crohn’s will need >1 surgery. May need for strictures, fistulaes, adhesions, resections (especially if unresponsive to treatment). May be due to cancer or risk of haemorrhage

Question 8

Causes for anorexia in CD

Answer 8

• organic causes: strictures/sepsis/early satiety/altered taste, drugs (opioids), chronic inflammation, dietary restrictions, inflammatory cytokines (IL1, IL6, TNFa, IFNy) can lead to weight loss and cachexia, adiponectin/leptin/resistin/GP130 several mechanisms proposed, psychosocial impact of disease
• Management: may need psychotherapy, need PN (watch for RFS)
• AN should be diagnosed when all organic causes excluded