Crohns Disease Flashcards
Age peaks for Crohns
15-30 and then 60-80
Where does it affect?
Anywhere from mouth to anus - ANY PART of GI tract
Crohns inflammation
- Transmural
- Deep ulcers and fissures
- Non-continious - skip lesions
Microscope of Crohns
Non-caseating granulomatous inflammation
Consequence of transmural inflammation of Crohns
- Can get fistulas
- Most common is peri-anal, but can also be entero-enteric, recto-vaginal, entero-cutaneous or entero-vesicular
RF for Crohns
- Mainly familial link
- Smoking increases risk and relapse risk
UC vs Crohns - site, macroscopic changes and inflammation
- Site - UC just large bowel, Crohns entire GI tract
- Inflammation - mucosal in UC, transmural Crohns
- Macro - UC continious, psuedopolyps and ulceration. Crohns skip lesions, fissures and deep ulcers (cobblestone), fistulas
UC vs Crohns microscopic changes
UC:
* Crypt abscess formation
* Reduced goblet cells
* Non-granulomatous
Crohns:
* Granulomatous (non-caseating)
Symptoms of Crohns
- Episodic abdominal pain - colicky, varies in site
- Diarrhoea - chronic, may contain blood/mucus
- Systemic - malaise, anorexia, low grade fever, malabsorption/malnourishment (children can be failure to thrive)
- Oral aphthous ulcers
Extra-intestinal features of Crohns - MSK
- Enteropathic arthiritis (esp sacroiliac and other large joints)
- Nail clubbing
- Metabolic bone disease (secondary to malabsorption
Extra-intestinal features Crohns - skin
- Erythema nodosum - tender, purple SC nodules on shins
- Pyoderma gangrenosum - erythematous papules or pustules that develop into deep ulcers
Crohns features - eyes
- Episcleritis
- Anterior uveitis
- Iritis
Crohns extra-intestinal features - hepatobiliary
- Primary sclerosing cholangitis (more associated with UC though)
- Cholangiocarcinoma - due to association with PSC
- Gallstone disease
Renal manifestations of Crohns
Renal stones
Blood tests for ?Crohns
- FBC - anaemia
- LFT - albumin low? secondary to systemic illness
- CRP - inflammation
Stool tests for ?Crohns
- Faecal calprotectin
- Stool MC&S - exclude infective cause
Gold standard investigation Crohns
Colonoscopy - show inflammation and take biopsies to diagnose
How to classify severity of Crohns
- Montreal score
- Includes age, location, behaviour (eg stricturing, penetrating), perianal disease present?
Imaging for Crohns disease
- MRI small bowel - assess and monitor involvement and severity, inflam or fistulating disease can be assessed via MRI
When is examination under anaesthesia done for Crohns?
- MRI imaging assesses for fistulating perianal disease
- Can then consider EUA to examine and treat any perianal fistula present
Acute presentation of Crohns imaging
- CT scan abdomen pelvis - check for evidence of bowel obstruction (from stricture) or bowel perforation (from full thickness penetrating disease)
Management - overall Crohns
- Refer for Gastroenterology if suspect to confirm and initiate treatment
- Complex disease may need IBD MDT meeting - gastro, general surgery, radiology, IBD specialist nurse, dieticians
- Acute flare = acute admission usually to treat
Inducing remission of Crohns disease
- Acute flare - corticosteroid therapy first line to induce remission
- Fluids
- Prophylactic heparin with antiembolic stockings - prothromotic state IBD
- Low residue diet (low fibre)
- Avoid anti-motility drugs (eg loperamide) - precipitate toxic megacolon
What to use if corticosteroids do not work to induce remission Crohns?
- Immunosupressive agents eg Mesalazine (aminosalicylate) or Azathioprine
- OR biological agents eg Infliximab or Adalimumab
Maintaining remission in Crohns
- Azathioprine 1st line - methotrexate as alternative
- Smoking cessation
- IBD nurse specialist input
- Low fibre diets can be beneficial
Monitoring of Crohns disease complications?
- Colonoscopic surveillance
- Offered to people who have had disease for more than 10 years with more than 1 segment of bowel affected
- Due to increased risk of colorectal malignancy
When is surgical management offered for patients with Crohns?
- Failed medical management
- Severe complications eg stricture or perforation
- Always a BOWEL SPARING approach to prevent short gut syndrome
Common operations required for patients with Crohns disease
- Ileocaecal resection - removal of terminal ileum and caecum with anastomosis
- Small bowel resection
- Surgery for peri-anal disease - eg abscess drainage, seton insertion or laying open fistula
- Stricturoplasty - division of stricture that is causing obstruction - can also consider balloon dilation if short, straight single stricture
Crohns disease - pre op importance
- High risk patients to operate on
- Optimise pre op - treat acute flares and manage nutrition
- If active severe flare, primary bowel anastomosis should not be performed - or at least not without defunctioning stoma - due to risk of breakdown of anatomosis
Complications of Crohns - GI
- Fistula
- Strictures
- Recurrent perianal fistula –> perianal abscess and then sepsis
- GI malignancy - 3% colorectal cancer risk and SB cancer 30x more common
Complications Crohns - extraintestinal
- Malabsorption - growth delay, osteoporosis (long term steroid or malabsorption)
- Increase risk of gallstones - reduced reabsorption of bile salts at terminal ileum
- Increase risk of renal stones - malabsorption of fats in small bowel = calcium stays in lumen, oxalate then absorbed freely = hyperoxaluria and formation of stones
