Crohns & Ulcerative Collitis

Question 1

Pathophysiology of Crohn’s & UC

Answer 1

1. Genetics - NOD2 dysfunction
2. Mucosal immune responce
   
   • Crohns
     
     • IFNy ⇒** T_H1 **⇒ IFNy
     • TGFB/ IL6 ⇒** T_H17 **⇒ IL17, 21, 22
   • UC
     
     • IL4 ⇒** T_H2 **⇒ IL4, 5, 13
3. Epithelial barrier defects
4. Microbiota

Question 2

What are the features & differences between Crohns & UC?

Answer 2

• Crohns
  
  • Entire GIT
  • Transurmural, segmental, thick cobblestone granulomas
  • T_H1 & T_H17
• UC
  
  • Rectum (proctitis ½), L-sided colitis (⅓) & pancolitis (¼)
    
    • Backwash ileitis: proximal to ileocaecal valve
  • Hyperaemic mucosa, continuous, pseudopolyps & ulcers
  • T_H2

Question 3

What are differences in symptoms & signs of Crohns & UC?

Not including extraintestinal signs

Answer 3

• Crohns
  
  • Diarrhoea & urgency
  • Abdo pain
  • Weight loss/ failure to thrive
  • Fever, malaise, anorexia
• UC
  
  • Diarrhoea +/- mucus/ blood
  • Crampy abdo discomfort
  • Fever, malaise, anorexia, weight loss

Question 4

Outline the extraintestinal signs in IBD

Answer 4

PIESAC

• Pyoderma gangrenosum
• Iritis, conjunctivitis, episcleritis
• Erythema nodosum
• Sacrolitis, arthritis
• Ankylosing spondylitis
• Clubbing, cholangiocarcinoma, fatty liver

Question 5

How to you access the severity of UC?

Answer 5

Truelove & Witts criteria modified including CRP

• Motions /day [<4-6<]
• Rectal bleeding [small-mod-large]
• TºC @ 6am [<37.1-37.8<]
• Resting pulse [<70-90<]
• Haemoglobin [>110-105>]
• ESR/ CRP [<30< / <16-45<]

Question 6

Outline the complications of UC

Answer 6

Complications of UC

• Perforation & bleeding
• Toxic megacolon (mucosal islands, d=>6cm)
• Venous thrombosis (give prophylaxis)
• Colonic cancer

Question 7

Outline the mechanism of action of 5-aminosalicylic acid

Answer 7

Anti-inflammatory aminosalicylate that acts predominantly in the gut

Used in UC & Crohns

eg Mesalazine

Question 8

Outline the mechanism of action of Azathioprine

Answer 8

Purine analogue immunosuppressor inhibiting DNA synthesis in most-proliferating cells

Question 9

Outline the medical treatment for UC

Answer 9

Inducing remission

• 5-aminosalicylic acid
  
  • eg Sulfasalazine/ mesalazine
• Corticosteroids
  
  • eg Prednisolone 20mg/d +/- 2/d steroid foams PR (hydrocortisone) or Prednisolone retention enemas

2nd line

• UP oral prednisolone **40mg/d **(reducing over 6wks)
• Azathioprine (metabolite 6-mecaptopurine)

3rd line

• Admit - NBM, IV fluids
• Hydrocortisone 100mg/6hr IV + rectal hydrocortisone
• No improvement ⇒ colectomy or rescue therapy (ciclosporin/ infliximab)

Immunomodulation if no remission with steroids.

Question 10

Outline the surgical treatment for UC

Answer 10

• Proctocolectomy + terminal ileostomy
• May be possible to retain ileocecal valve
  
  • Colectomy with ileo-anal pouch

Question 11

Outline complications of Crohns

Answer 11

Complications of Crohns;

• Small bowel obstruction
• Toxic megacolon (>6cm, rarer than UC)
• Abscess formation
• Fistulae (10%)
• Perforation & bleeding
• Colon cancer

Question 12

Outline the medical and surgical treatments of Crohns

Answer 12

Mild: Prednisolone 30mg/d PO

Severe:

• Admit + fluids
• IV steroids
• Hydrocortisone
• Metronidazole
• Infliximab/ adalimumab

Question 13

Outline the mechanism of action of Infliximab & Adalimumab

Answer 13

TNFa inhibitor

TNFa promotes Neutrophil activity, granuloma formation, complement activation and CD4+ T-Cells