Sundry Disorders of the Intestines

Question 1

colonic diverticulosis

Answer 1

*herniation of the mucosa and submucosa through the muscularis propria
*occurs at sites of relative weakness of the wall of the colon, where the vasa recta penetrate the muscularis propria
*most commonly seen in the sigmoid colon

Question 2

complications of diverticulosis

Answer 2

*diverticulitis
*diverticular hemorrhage

Question 3

diverticulitis - overview

Answer 3

*microperforation of a diverticulum at a site of mucosal erosion
*inflammation of diverticula with wall thickening
*inflammatory process typically contained by pericolonic fat and omentum

Question 4

diverticulitis - clinical presentation

Answer 4

*progressive steady LLQ abdominal PAIN & fever
*typically with altered bowel habits (constipation or diarrhea)
*leukocytosis on CBC

note - bleeding is NOT part of diverticulitis

Question 5

diverticulitis - treatment

Answer 5

*antibiotics to cover gram negative rods and anaerobes (ciprofloxacin & metronidazole)

Question 6

complications of diverticulitis

Answer 6

*abscess
*colovesical fistula
*stricture

note - all of these complications require surgical intervention

Question 7

diverticular hemorrhage - overview

Answer 7

*rupture of the vasa recta associated with a diverticulum, due to thinning of the vessel wall where it crosses over the dome of the diverticulum (arterial bleeding)
*most common cause of major lower GI bleeding

Question 8

diverticular hemorrhage - clinical presentation

Answer 8

*abrupt onset of PAINLESS hematochezia (rectal bleeding) and significant blood loss, requiring hospitalization and blood transfusion
*typically stops spontaneously with supportive care
*dx is made by colonoscopy

Question 9

intestinal ischemia syndromes

Answer 9

*acute mesenteric ischemia
*chronic mesenteric ischemia
*ischemic colitis

Question 10

celiac artery

Answer 10

provides arterial blood to foregut:
-stomach
-duodenum
-pancreas
-liver/GB
-spleen

Question 11

superior mesenteric artery

Answer 11

provides arterial blood to midgut:
-jejunum
-ileum
-R colon

Question 12

inferior mesenteric artery

Answer 12

provides arterial blood to hindgut:
-left colon (distal transverse to proximal rectum)

Question 13

blood supply to rectum

Answer 13

branches of internal iliac artery

Question 14

acute mesenteric ischemia - overview

Answer 14

*predominantly caused by embolic phenomena (esp in the SMA)
*embolic events are typically associated with sudden onset of severe abdominal pain
*abdominal pain is poorly localized, with severity “out of proportion to findings on physical exam”
*suspect emboli in patients in CHRONIC ATRIAL FIBRILLATION

Question 15

nonocclusive mesenteric ischemia (NOMI)

Answer 15

*low flow state associated with hypotension, CHF, vasopressors, cocaine, and digitalis
*microvascular vasoconstriction, with patent large vessels
*pain is not as prominent as with other forms of acute mesenteric ischemia

Question 16

diagnosis of acute mesenteric ischemia

Answer 16

*CTA is the diagnostic modality of choice
*high sensitivity & specificity
*allows for nonsurgical therapy

Question 17

treatment for acute mesenteric ischemia

Answer 17

*EMBOLECTOMY
*SURGICAL BYPASS

Question 18

mesenteric venous thrombosis

Answer 18

*clotted vein
*usually more of a SUBACUTE presentation
*clinical presentation: abdominal pain, nausea/vomiting
*commonly seen in people with a hypercoagulable state

Question 19

treatment of mesenteric venous thrombosis

Answer 19

*IV heparin
*thrombolytic therapy
*oral anticoagulation
*surgery if bowel infarction is evident

Question 20

portal venous thrombosis

Answer 20

*most cases are associated with cirrhosis
*pathophysiology is sluggish flow in portal vein
*commonly a chronic situation

Question 21

acute portal vein thrombosis

Answer 21

*usually presents with progressive abdominal pain and persistent fever
*most significant clinical outcome is associated MVT and intestinal infarction

Question 22

chronic mesenteric ischemia

Answer 22

*classic sx: postprandial abdominal pain (10-30 min after eating), sitophobia (aversion to eating), and weight loss
*95% related to atherosclerosis
*dx: hx, exclusion of other causes, and demonstration of narrowing of at least 2 of the 3 major mesenteric arteries

Question 23

treatment options for chronic mesenteric ischemia

Answer 23

*endovascular stent
*surgical bypass (single vs. double artery bypass)
*the SMA is the focus

Question 24

colonic ischemia

Answer 24

*sudden onset of mild crampy LLQ abdominal pain
*followed by passage of red or maroon stools within 24 hours
*mild to moderate tenderness to palpation on exam
*thickened colon on CT
*segmental ulceration with rectal sparing on colonoscopy

Question 25

treatment of colonic ischemia

Answer 25

*IV fluids
*bowel rest
*optimize cardiovascular state
*broad-spectrum antibiotics
*surgery indicated for: clinical evidence of colon infarction, failure to improve after 2-3 weeks

Question 26

arteriovenous malformations (AVMs)

Answer 26

*abnormal ectatic mucosal vessels with direct connection between arteries and veins WITHOUT an intervening capillary bed
*can be found throughout the GI tract
*a common cause of iron-deficiency anemia

Question 27

hereditary hemorrhagic telangiectasia (HHT)

Answer 27

*associated wtih 2 mutations of genes involved with vascular development and repair (endoglin on chr 9 and activin receptor-like kinase-1 on chr 12)
*AVMs can develop anywhere in the body
*most commonly on skin & mucous membranes and usually present with nosebleeds or GI bleeding

Question 28

diverticulum

Answer 28

a sac-like protrusion of the colonic wall created by the herniation of the lining mucosa through a defect in the muscular layer of the GI tract