diseases of colon Flashcards
colon sphincters
ileocecal valve, internal and external anal sphincters
Does colon have villi
no
Functions of colon
absorption of water and ions (ascending), bacterial fermentation of nonabsorbed nutrients (transverse and descending), storage and elimination (descending and rectum)
irritable bowel disease symptoms
Suggestive symptoms (e.g., diarrhea, crampy abd pain, bleeding) lasting > 2 weeks , Negative work-up for other causes of colitis (infection, ischemia, medications), Extraintestinal symptoms
How is irritable bowel disease diagnosed
Direct visualization and biopsy
signs/symptoms of ulcerative colitis
Diarrhea, Weight loss, Fatigue, Lower abd pain, Hematochezia , Mucus in stool, Tenesmus
signs/symptoms of Crohns
Diarrhea, Weight loss, Fatigue, Mid or lower abd pain, Nausea/vomiting, Fistula symptoms
For Crohns and ulcerative colitis List: bowel region, fistulae/abscess, strictures and distribution
Crohns: entire GI tract, fistulae and abscesses common, strictures common, skip lesions. UC: Colon, NO fistulaes or abscesses, no strictures, diffuse
For Crohns and ulcerative colitis List: location of inflammation, location and type of ulcers, presence of fibrosis, presence of granulomas
Crohns: transmural inflammation, deep linear ulcers, lots of fibrosis, 20% get granulomas. UC: mucosal +/- smooth muscle inflammation, superficial confluent ulcers, mild to no fibrosis, no granulomas
For Crohns and ulcerative colitis List whether it has each of the following: obstruction, malabsorption, malignant potential, recurrence after colectomy, toxic megacolon
Crohns: obstruction YES, malabsorption YES, malignant potential with colonic involvement, recurrence after colectomy common, toxic megacolon NO. UC: obstruction NO, malabsorption NO, malignant potential YES, recurrence after colectomy NO, toxic megacolon YES
Extraintestinal manifestations of ulcerative colitis
eye: scleritis, episcleritis. Skin: Pyoderma gangrenosum (ulcers on lower extremities), erythema nodosum (nodules with erythrodermous patch). Liver: Primary sclerosing cholangitis (PSC- fibrosis of hepatic bile ducts). Joints: Sacroiliitis, Ankylosing spondylitis
How is IBD (crohns and UC) treated
Corticosteroids during flares, 5-aminosalicylates, immunomodulators, TNF-alpha antagonists, surgery (colectomy, partial small bowel resection or stricturoplasty)
Colon cancer and UC
risk increases with disease duration
What is microscopic colitis
Chronic secretory diarrhea that is watery and non-bloody (4-10 stools per day, minimal nocturnal or fasting symptoms). Mainly occurs in females age 50-80, autoimmune but trigger is unknown.
Microscopic colitis diagnosis
Colonoscopy usually normal. Biopsy shows Lymphocytic infiltration of mucosa and SM (LC) and Thickened collagenous band (CC)
Types of microscopic colitis
Based on histology: lymphocytic (chronic inflammation) or collagenous (thickened subepithelial collagen band with lymphocytic surface injury)
microscopic colitis treatment
antidiarrheals (loperamide, diphenoxylate), bismuth, topical steroids
Ischemic colitis triggers
vasospasm, dehydration, hypotension, cardiopulmonary insult (MI, PE)
ischemic colitis locations
watershed vascular areas: splenic flexure, rectosigmoid
Ischemic colitis presentation
- Abrupt-onset, crampy, lower abdominal pain. Urgent need to defecate. Mild diarrhea and/or hematochezia.
- Abrupt-onset, crampy, lower abdominal pain. Urgent need to defecate. Mild diarrhea and/or hematochezia.
ischemic colitis endoscopic findings
edema, ulceration +/- bleeding confined to vascular region
ischemic colitis recovery time
1-2 weeks
Ischemic colitis diagnosis:
Colonoscopy or flexible sigmoidoscopy with biopsy are gold standard. A KUB x ray may show thumbprinting of colon mucosa, but not sensitive. Also, contrast CT may show colon wall thickening, pericolonic inflammation or decreased perfusion
Less common causes of ischemic colitis
vasculitis (lupus), substance abuse, meds (estrogen), protein C/ S deficiency, Factor V leiden deficiency, marathon running
ischemic colitis treatment
support, antibiotics, volume support
Symptoms of infectious colitis
•Inflammatory diarrhea +/- hematochezia. Short duration, recent travel/sick contacts, Abx use,
Risk factors for diverticulosis
western countires (low fiber diets, increased intracolonic pressure), >50% are in elderly
Symptoms and cause of diverticular hemorrhage
usually in right colon, vasa recta withing dome of diverticulum. Causes painless Painless hematochezia, often heavy, typically stops w/in 2-3 days. Does NOT occur with diverticulitis
What is acute diverticulitis
Fecolith obstructs diverticulum causing distension from bacterial gas and neutrophils, microperforation, abscess, macroperforation with peritonitis.
Acute diverticulitis symptoms
LLQ pain, nausea, fever
Diverticulitis management
Diagnose with CT or MRI. Treat with oral/ IV antibiotics, abscess drainage and/or surgery. Strictures may require dilation or resection
Etiologies of lower GI bleeding
diverticulosis, arteriovenous malformations, colitis, neoplasm, radiation colitis, post-polypectomy or biopsy, internal hemorrhoids, rectal ulcer, anal fissure,
Causes of colonic obstruction
adenocarcinoma of colon or rectum (90%), volvulus, benign strictures from acute divertiulitis.
Obstructive colon cancer prodrome
change in stool frequency or caliber
Volvulus
typically involves the cecum or sigmoid colon, where a colonic loop twists around on its mesentery, resulting in strangulation and luminal obstruction
colonic obstruction presentation
diffuse or upper abdominal discomfort, distension, and nausea/vomiting. The emesis may be feculent. Absence of stool passage (obstipation)
How is colonic obstruction treated
surgical resection or metal stent
