IBD Vs Crohns?

Question 1

What are the causes and pathophysiology of Crohns

-how does this link to the presentation

Answer 1

Genetic => NOD 2 pathogen recognition protein
Environmental => unclear but smoking, diet rich in refined sugars
-triggered by pathogens

Full thickness inflammation => granuloma formation
Chronic inflammation => stricture (pain) and perianal fistula formation from scarred bowel => obstructions
Skip lesion inflammation => diarrhoea without tenesmus

Can lead to malabsorption => vitamin, nutrient deficiencies => weight loss, fatigue (anemia)

• terminal ileum most commonly affected => bile acid cannot be absorbed
• bile acid needed for fat and B12 uptake
• fats in stool (steatorrhea) binds to Ca instead of oxalate => oxalate absorbed and forms kidney stones

Question 2

What is the cause and pathophysiology of ulcerative colitis

-how does this link to the presentation

Answer 2

Genetic and environmental (smoking and appendectomy are protective)
-autoimmune triggered by inflammatory response to colonic bacteria

Starts in the rectum and extends proximally

• only involves mucosa => crypt abscesses, goblet cell depletion => mucosa destroyed => bleeding
• continuous inflammation causes frequent colonic contractions => urgent diarrhoea and tenesmus (crampy pain)
• inflammation also thins colon walls => increased risk of toxic mega colon and perforation

Question 3

What are the extra gastrointestinal manifestations of IBD

Answer 3

A ESCAPE
-can be found in both but uveitis and PSC more common in UC

Aphthous ulcers
Eyes (iritis, uveitis)
Sclerosing cholangitis
Clubbing
Arthritis enteropathic
Pyoderma gangrenosum 
Erythema nodosum (inflammation of adipocytes)

Question 4

What investigations would you do for IBD

Answer 4

FBC

• chronic inflammation => anemia, leukocytosis, thrombocytosis
• macrocytic anemia => folate/B12 deficiency
• microcytic anemia => Fe deficiency (reduced uptake/blood loss)

Elevated CRP, ESR

LFTs => assess for cholestatic pattern of sclerosing cholangitis

Fe studies => changes consistent with Fe deficiency
Serum B12, folate => low due to malabsorption

Stool studies => high fecal calprotectin, rule out CDiff

Colonoscopy => assess for pseudopolyps or cobblestoning.

Question 5

What imaging would you consider and what might you find

Answer 5

Plain AXR or CT

• thickening of affected areas in CD
• thinning of affected areas in UC
• sacroilitis, ankylosing spondylitis

Question 6

What are the other possible differentials?

Answer 6

Inflammatory/infective

• Infective colitis => contact with other ill people, travel history
• Appendicitis => severe abdo pain in RIF
• Diverticulitis => abdo pain in LIF
• PID => sexual history with abdo pain
• GI TB => systemic symptoms

Trauma

• Radiation colitis => recent radiotherapy, v similar presentation to UC
• Ectopic

Autoimmune
-Crohns/UC

Neoplasticism
-Bowel cancer

Endocrine
-Endometriosis => deep back pain, associated with menstruation

Functional
-IBS => abdo pain, bloating, diarrhoea, constipation

Question 7

How would you manage Crohns

• flare up
• remission

Answer 7

Flare up

• prednisolone or mesalazine
• may add azathiopurine or methotrexate
• may add adalimumab, inflixumab

Surgery may be needed
-risks include short bowel syndrome, perforation, bleeding

Remission
-Azathiopurine or methotrexate

Question 8

How would you manage UC

• flare ups
• remission

Answer 8

Flare ups

• sulfasalazine
• CS monotherapy
• may add calcineurin inh (tacrolimus, ciclosporin)
• may consider TNFa inh

Surgery may be an option

Remission
-Sulfasalazine