EXAM #1: SMALL BOWEL PATHOLOGY Flashcards
What is the definition of IBD?
Inflammatory Bowel Disease
What two diseases comprise IBD?
Crohn’s Disease
Ulcerative Colitis
What is the postulated etiology of IBD?
Abnormal immune response to gut flora
What lymophocyte is implicated as the “prime culprit” in IBD?
T-cells; there is an impairment of T-cell downregulation
What antibody is helpful in diagnosis of UC?
ANCA
What antibody is helpful in diagnosing Chron’s Disease?
ASCA
In addition to T-cell dysregulation, what pathogenic feature is associated with CD?
Chronic Delayed Hypersensitivity
In addition to T-cell dysregulation, what pathogenic feature is associated with UC?
Excessive Th2 stimulation
What part of the GI tract is involved in Chron’s Disease? What is least common?
Any region from “mouth to anus,” but most commonly the terminal ileum
(Rectum is least common)
What are the hallmark symptoms of Chron’s Disease?
- Intermittent diarrhea (non-bloody)
- Right lower quadrant abdominal pain
- Fever
How many walls of the bowel are involved in Chron’s Disease?
ALL– i.e. this is “transmural” or full thickness inflammation of the bowel
What type of inflammation is associated with Chron’s Disease?
Lymphoid aggregates with granulomas
Describe the gross appearance of Chron’s Disease?
1) Skip lesions
2) Cobblestone mucosa (healing)
4) Rubber hose sign (fibrosis causing thickening of bowel wall)
5) Creeping fat (pulling in of mesenteric fat with fibrosis)
What is a string sign? What disease is this associated with?
In Chron’s Disease, narrowing of the lumen due to fibrosis causes the appearance of a “string” on barium study
What are the major complications of Chron’s Disease?
1) Malabsorption and nutritional deficiency
2) Calcium oxalate nephrolithiasis
3) Fistula formation
4) Carcinoma
What are the extraintesintal manifestations associated with Chron’s Disease?
- Arthritis
- Erythema nodosum
- Uveitis
What types of arthritis are associated with Chron’s Disease?
1) Peripheral joint
2) Ankylosing spondyliitis
3) Migratory polyarthritis
What is the relationship between smoking and Chron’s Disease?
Smoking INCREASES risk for Chron’s
Where is the inflammation localized in Ulceractive Colitis?
Mucosa/ Submucosa
How does Ulceractive Colitis differ from Chron’s?
1) Extends in a cont. fashion i.e. NO SKIP LESIONS
2) NO granulomas
3) Thinning, not a thickening of the bowel
4) Involves all of the “tube”
What are the clinical features of Ulceractive Colitis?
1) Bloody mucoid diarrhea
2) Left lower quadrant abdominal pain relieved by defecation
What is pancolitis?
Involvement of the entire colon in Ulceractive Colitis
What is backwash ileitis?
Inflammation of the distal ileum in UC due to “backwash” of cecal contents
What are the major complications of Ulceractive Colitis?
1) Toxic megacolon
2) Perforation
3) Carcinoma
What are the class gross features of Ulcerative Colitis?
- Pseudopolyps
- Loss of haustra
What is a pseuodpolyp seen in Ulceractive Colitis?
Bumps on the surface of the bowel in UC–represents areas of healing
What radiologic sign is associated with UC?
Lead pipe sign on X-ray
This represents the loss of haustra i.e. a smooth tube seen on X-ray
What extraintestinal manifestation is associated with UC?
Primary sclerosing cholangitis (Disease/ blockage of the bile ducts due to fibrosis)
What are the two main factors that determine the progression of UC to carcinoma?
1) Extent of colonic involvement
2) Duration of disease (greater than 10 years= high risk)
What is the relationship between smoking and UC?
Smoking is PROTECTIVE against UC
What type of inflammation is seen in UC?
Crypt abscess formation i.e. neutrophilic infiltration colonic “crypts” i.e. glands
What is Ischemic Bowel Disease?
Ischemic damage the colon due to occlusion of the mesenteric vessels
Where is the bowel most likely to become ischemic?
Watershed areas:
1) Splenic flexure
2) Rectosigmoid
What vessels meet at the splenic flexure?
SMA and IMA
What vessels meet at the rectosigmoid flexure?
IMA
Hypogastric
What are the causes of Ischemia Bowel Disease?
1) Atherosclerosis/ thrombosis
2) Arterial embolism
3) Low flow states (CHF)
4) Venous thrombosis from hypercoaguability
What typically causes transmural infarction of the bowel?
Acute vascular obstruction
What typically causes mural and mucosal infarction?
Hypoperfusion
What artery is most commonly occluded in a transmural infarction?
SMA (typically due to atherosclerosis)
What is the clinical picture of a patient with a transmural infarction of the bowel?
1) Older adult
2) Acute abdomen
3) Rapid progression to shock
100% mortality if NOT treated early
What is the major complication of chronic bowel ischemia?
Stricture leading to obstruction
What is angiodysplasia?
Vascular dilation and malformation of submucosal or mucosal blood vessels in cecum and ascending colon
What is the predominant symptom associated with angiodysplasia?
Significant hematochezia (due to rupture)
