CPT2: GI (Crohn's/ Ulcerative colitis)

Question 1

Describe the anatomy of the colon

Answer 1

Terminal ileum - colon starts after this

Accending colon

Transverse colon

Descendin colon

Sigmoid colon

Rectum

Question 2

Where does crohn’s disease occur?

What are the characterisitics?

Inflammation?

Answer 2

Crohn’s Disease

• Can affect any part of the entire GI tract (rectum to mouth)
• Characterised by Skip lesions
• Commonly the ileocaecal area or small intestine
• Transmural inflammation
  
  • Inflammation from mucosa to serosa

Question 3

Where does Ulcerative colitis occur?

Characterisitics?

Inflammation

Answer 3

Ulcerative Colitis

• Affects colon only
• Continuous lesions
• Commonly the rectum and sigmoid colon (proctitis) with proximal spread
  
  • Always starts at rectum and moves backwards
• Superficial inflammation
  
  • Affects mucosa only

Question 4

View picture - shows difference between continuous inflammation in Ulcerative colitis and skip lesions in Crohns.

Turn over

Answer 4

Differences inside lumon

1. Crohns
   
   1. fissure - trasmural damage
2. Ulcerative colitis
   
   1. Polups - less affected areas of mucosa

Question 5

look at picture

Question 6

Symptoms and signs of Crohns and Ulcerative colitis

Answer 6

Question 7

Disease charactersitics of inflammatory bowel disease

Answer 7

Episcleritis is inflammation of the episclera, the lining of the sclera (white of the eye)

Erythema Nodosum is a skin condition that is characterised by painful red, rounded lumps which appear on the shins and around the ankles, and less commonly the thighs and forearms

Ankylosing spondylitis is inflammation of the joints in the spine leading to new bone formation potentially bone fusion, affecting posture

Question 8

Complications of inflammatory bowel disaese

Answer 8

Complications:

• Toxic megacolon (dilation of the bowel, risk of perforation)
  
  • Perforation - hole in colon
• Intestinal strictures (bowel obstruction)
  
  • Damage and repair leads to scar tissue which narrows lumon of colon. Food can get stuck and cause bowel obstruction
• Malnutrition
  
  • Inflammation so reduced absorption of water and nutrients
• Anaemia (B12/folate deficiency or iron deficiency from blood loss)
  
  • Terminal ileum - B12 absorbed
• Perforation of the small intestine or colon (Life threatening acute bleeding and infection)
• Fistulas between the intestine and adjacent structures, such as peri-anal skin, bladder, and vagina (Crohn’s)
  
  • Cause tunnel betwene adjacent structures e.g. bladder
• Colorectal cancer
• Osteoporosis
  
  • Reduced Ca2+ absorption
• Venous thromboembolism (inflammatory conditions increase risk)
  
  • Inflammation produces proinflammatory mediatos so promotes pro-thrombic enviroment

Question 9

Epidemiology of Crohns and Ulcertative colitis

Answer 9

Crohn’s disease

• 157 with diagnosis of Crohn’s for every 100,000 people
• Peak age of onset is between 15 and 40 years
• Smokers
• Highest incidence in Northern Europeans/Americans
• M=F

Ulcerative Colitis

• 243 with diagnosis of ulcerative colitis for every 100,000 people
• The peak age of onset is between 20 and 40 years of age, second peak 60 years
• Non Smokers/ex smokers
• Highest incidence in Northern Europeans/Americans
• M=F

Question 10

Aetiology

Answer 10

Cause of both conditions is unclear

• Genetics
  
  • Higher rate of Crohn’s and UC if a family member is affected
• Environment
  
  • Smoking, ?dietary, altered microbiome
    
    • Smoking increases risk of Crohns, but decreases risk of UC
• Infective/Inflammatory
  
  • Impaired barrier function of epithelium allows bacteria to enter causing immune activation and inflammation (M. paratuberculosis).
  • Overproduction of tumour necrosis factor alpha (TNFa) and other pro-inflammatory cytokines

Question 11

Pathophysiology

Answer 11

Question 12

How is diagnosis confirmed?

Answer 12

FBC/U&E/LFTs:

• High ESR
• High CRP (inflammatory)
• High WCC (inflammatory)
• ?Na and K imbalances
  
  • Low Na+/K+ in diahorrea
• ?Low albumin
• ?Anaemia – Iron deficiency, anaemia of chronic disease, folate/B12 deficiency

Endoscopy + biopsy/CT:

• Site and extent of disease
• Cobbling, fistulates, pustles, transmural, superificial

History:

• No. of loose movements/day, blood in stool, malnourishment, smoking history, family history

Stool culture:

• To exclude infective causes

Question 13

Treamtments

Answer 13

• 5-ASA not licensed in Crohn’s – No proven value, but occasionally used to try it before progressing up ladder
• Methotrexate no proven value in UC
• Steroids only used to induce remission – not used for maintenance