IBD Flashcards
What is IBD/
umbrella term for two main diseases causing inflammation of the GI tract: Ulcerative Colitis and Crohn’s disease. They both involve inflammation of the walls of the GI tract and are associated with periods of remission and exacerbation.
Whats the prevalence of Crohn’s disease?
25-100/100,000
Whats the prevalence of ulcerative colitis?
80-150/100,000
Where are the highest incidence rates of IBD?
Northern Europe, UK, North America
How does race and ethnic group impact the incidence and prevalence of IBD?
Rates are lower in Hispanic and Asian people compared with White individuals
Jewish people are more prone to IBD than any other ethnic group
What age is IBD usually diagnosed?
Crohns - 15-35
UC - 15-35 and 60-80
Whats the aetiology of IBD/
Unknown but known interaction between genetic susceptibility, environment, intestinal microbiota and host immune response
What are the genetic factors of IBD?
Up to 1/5 pt with CD and 1/6 pt with UC will have a 1st degree relative with the disease
NOD2 gene
T cell autoimmune
What are the environmental aetiological factors of IBD?
Smoking - smoking can exacerbate CD and increase risk of disease recurrence after surgery. Nicotine has been shown to be an effective treatment in those with UC
NSAIDs- associated with onset and flare ups of IBD
Poor hygiene - lower risk of developing CD (i.e. decreased microbial exposure as a child increase risk)
Nutritional factors - studies are equivocal but high sugar/fat and low fibre intake may play a role. Breast-feeding can provide protection against development of IBD
Psychological - chronic stress and depression
Appendicectomy - protective against development of UC but increases risk of CD
Antibiotic use may increase risk
How may intestinal microbiota relate to aetiology of IBD?
Those with IBD have a reduced diversity of microbial species
Increased E.coli adherence to ileal epithelial cells in CD
Bacterial antigens
Defective chemical barriers or intestinal defensin
Impaired mucosal barrier function
Where in the bowel does Crohn’s disease affect?
Any part of GI tract from mouth to anus but has a particular tendency to affect the terminal ileum and ascending colon
It can involve one small area of the gut, such as the terminal ileum, or multiple areas with skip lesions. It may also involve the whole of the colon
What is total colitis?
When UC affects the whole of the colon also known as pancolitis
What is proctitis?
When UC affects the rectum alone
What is left-sided colitis?
When UC affects the sigmoid and descending colon
What is extensive colitis?
When UC affects the whole colon
What is backwash ileitis?
Up to 35% of patients with UC develop inflammation in the terminal ileum, which historically, has been attributed to backwash of colonic contents into the terminal ileum
It’s a result of an incompetent ileoceacal valve
What is proctosigmoiditis?
UC affecting rectum and sigmoid colon
What macroscopic changes can be seen with Crohn’s disease?
Bowel appears bright red and swollen
Later small, discrete aphthoid ulcers with a haemorrhagic rim form
Later deeper longitudinal ulcers form which may develop into deep fissures involving the full thickness wall of the GIT
Fibrosis may follow with stricture formation
Mucous membrane appears cobble-stoned
Aggregations of inflammatory cells and lymphocytes infiltrate the bowel wall
Mesenteric lymph nodes may be enlarged (reactive hyperplasia)
Granulomas may be present in lymph nodes
What macroscopic changes can be seen in ulcerative colitis?
Mucosa looks reddened and inflamed
Mucosa is very friable
Shallow ulceration and marked pseudo-polyps
What microscopic changes are seen in Crohn’s disease?
Inflammation is transmural of the bowel
There is an increase in chronic inflammatory cells and lymphoid hyperplasia
In 50-60% of pt, granulomas are present (non caseating epitheliod cell aggregates with Langerhans giant cells)
Increased goblet cells
What microscopic changes are seen in ulcerative colitis?
Inflammation is superficial and limited to the mucosa (unless fulminant)
Chronic inflammatory cell infiltrate in the lamina propria
neutrophils migrate through the walls of glands to form crypt abscesses
depletion of goblet cells and mucin from gland epithelium
granulomas are infrequent
What serological testing can be done to distinguish between ulcerative colitis and Crohn’s disease?
Anti-saccharomyces cerevisiae antibody (ASCA) in crohns patients
Perinuclear anti-neutrophil antibodies (pANCA) in ulcerative colitis
What are extraintestinal manifestations of IBD/
Joint complications are most common - arthropathyes, arthralgia, ankylosis spondylitis, inflammatory back pain
Eyes - uveitis, epicleritis, conjunctivitis
Skin - erythema nodosum, pyoderma gangrenous
Liver and biliary tree - primary sclerosing cholangitis (UC), fatty liver, chronic hepatitis, cirrhoses
gallstones (crohns)
Anaemia + vit B12 deficiency
Nephrolithiasis (crohns)
Venous thrombosis
What are the clinical features of Crohn’s disease?
diarrhoea (can be bloody), abdominal pain (more predominant) and weight loss
Constitutional symptoms - malaise, lethargy, anorexia, nausea, vomiting, low-grade fever, peri anal disease, angular stomatitis, aphthous ulcers
Note that in 15% of pt there are no GI symptoms