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Flashcards in Pathophysiology of the colon Deck (28)
1

Diagnosis of Inflammatory Bowel Disease: when to suspect and how to diagnose

When:

Suggestive symptoms (e.g., diarrhea, crampy abd pain, bleeding) lasting > 2 weeks
Negative work-up for other causes of colitis (infection, ischemia, medications)
Extrai-ntestinal symptoms

How:

Imaging may be suggestive
Direct visualization and biopsy = gold standard

2

UC vs Crohn'd disease symptoms

UC: Diarrhea, Weight loss, Fatigue, Lower abd pain, Hematochezia, Mucus in stool, Tenesmus

Crohn's: Diarrhea, Weight loss, Fatigue, Mid or lower abd pain, Nausea/vomiting, Fistula symptoms

3

Macroscopic differences btwn UC and Crohn's

Crohn's: Entire GI tract, fistulae possible, strictures common, "skip lesions", transmural inflammation, deep/linear ulcers, marked fibrosis, granulomas (20%), can have obstruction, can have malabsorption, malignant potential with colonic involvement, common recurrence after colectomy, no toxic megacolon

UC: Colon only, no fistulae, no strictures, diffuse distribution, inflammation affects mucosa +/- SM, superficial/confluent ulcers, mild to no fibrosis, no granulomas, no obstruction, no malabsorption, yes malignant potential, no recurrence after colectomy, yes toxic megacolon

4

Extraintestinal manifestations of IBS

Mostly seen in UC

Eye: Scleritis, episcleritis

Skin: Pyoderma gangrenosum, erythema nodosum

Liver: Primary sclerosing cholangitis (PSC)

Joints: Sacroiliitis, Ankylosing spondylitis

5

IBD - management

Corticosteroids (topical or absorbed) - flares

Immunomodulators

TNF-alpha antagonists (IV or SC)

Surgery – colectomy, partial SB resection, or stricturoplasty

6

Risk of colon cancer with IBS

Goes up over time so need to screen and do random biopsies

Yearly colonoscopy after 7-8 years with disease

High-grade dysplasia or cancer, do colectomy

7

Microscopic colitis

Elderly females! (70 year old lady with mild watery diarrhea)

Fairly common

Ages 50-80, female : male ~ 15:1

Autoimmune, trigger unknown
Salt and water loss in colon

Presentation = mild, chronic secretory diarrhea
Watery, non-bloody
4-10 stools per day
Minimal nocturnal or fasting symptoms

Prognosis is good; managed medically

Mild association with celiac

Diagnosis is made with biopsy

8

2 types of microscopic colitis

1. Lymphocytic colitis
2. Collagenous colitis: thickened subepithelial collagen band

9

How is diagnosis made of microscopic colitis

biopsy

10

Ischemic colitis

90% of patients > 60 YO
Most patients have no vascular or GI dz
Fundamental insult = acute compromise in colonic bloodflow

Triggers: Vasospasm, Dehydration, hypotension, or cardiopulmonary insult (e.g. MI, PE)

Most commonly in watershed vascular areas (splenic flexure, rectosigmoid)

11

Presentation of ischemic colitis

Presentation = Abrupt-onset, crampy, lower abdominal pain

Urgent need to defecate

Mild diarrhea and/or hematochezia
Severe diarrhea or bleeding suggests another diagnosis

Endoscopic findings - edema, ulceration, +/- bleeding confined to a vascular region

Complete recovery within 1 – 2 weeks is typical

12

Infectious colitis

ACUTE Inflammatory diarrhea +/- hematochezia

Hx – short duration, travel, ill contacts, antibiotic use

13

Non-IBD colitis - management

Microscopic colitis – antidiarrheals (loperamide, diphenoxylate), Bismuth, topical steroids

Infectious colitis – support, +/- antibiotics

Ischemic colitis – support, antibiotics, volume support

Drug-induced – support, d/c offending drug

Radiation colitis – topical agents, endoscopic ablation

Surgery – rare; severe/refractory cases

14

Diverticulosis

> 50% in the elderly

Western > developing countries: increased intra-colonic pressure, Low-fiber diet

80% are asymptomatic

20% - diverticulitis, hemorrhage

15

Diverticular hemorrhage

5% of patients with diverticulosis

Usually from right colon

Vasa recta within the dome of diverticulum

Painless hematochezia, often heavy, typically stops w/in 2-3 days

Does NOT occur with diverticulitis

16

Acute diverticulitis

10-15% of patients with diverticula

Fecolith obstructs a diverticulum causing:
Distension from bacterial gas and neutrophils
Microperforation, abscess
Macroperforation with peritonitis

Symptoms: LLQ pain, nausea, fever

17

Diagnosis and treatment of diverticulitis

Diagnosis: CT or MRI

Treatment: Oral or IV antibiotics, abscess drainage, surgery

18

Lower GI bleeding

Bleeding distal to ligament of Treitz

Colon is most common site

Usually hematochezia

Less commonly, melena
Mortality ~1%

Ceases in 90% without intervention

Recurs frequently if cause is not identified

19

LGIB - etiologies

Diverticulosis

Arteriovenous malformations

Colitis (UC and Crohn's)

Neoplasm

Radiation colitis

Post-polypectomy or biopsy

20

Hematochezia after surgery or MI

Ischemic colitis

21

Lower GI bleed and Weight loss, new constipation, anemia

neoplasm

22

Lower GI bleed and painless sudden onset & cessation of bleeding, elderly patient

diverticulosis

23

Lower GI bleed and chronic abdominal pain and diarrhea

IBD

24

Lower GI bleed and acute dysentery, travel, ill contacts, or antibiotic use

infectious diarrhea

25

Lower GI bleed and chronic, microcytic anemia

Neoplasia or AVMs

26

Lower GI bleed and NSAIDs

drug-induced colitis

27

Lower GI bleed and history of pelvic radiation

Radiation proctitis

28

Colon obstruction (signs, causes, diagnosis, and treatment)

Causes: malignancy, foreign bodies, strictures, colvulus, adhesons

N/V, abd. distension, constipation or obstipation

Diagnosis: X-ray, confirmed with CT

Treatment: Admission to hospital, NPO, NGT tube decompression, Colonoscopy if suspected cancer or volvulus, Surgical resection is standard, Metal stent for select patients