GI 4

Question 1

Anatomy difference between colon and small bowel

Answer 1

Small bowel is attached to mesentery and aorta; free moving

Colon is attached to the abdominal wall and cannot move

Question 2

Patho SBO

Answer 2

• occurs when the normal flow of intestinal contents is interrupted
• focal point of narrowing–> obstruction of flow

Question 3

Causes of SBO

Answer 3

• Postoperative adhesions
• Hernias
• Intus susception
• Volvulus
• Crohn’s disease
• Gallstones

Question 4

Clinical SBO

Answer 4

• crampy abdominal pain
• nausea
• vomit a lot and feel better afterwards
• no passage of flatus/ stool
• more belching/hiccups
• abdominal distention
• abdominal tenderness

Question 5

Labs SBO

Answer 5

CBC with diff

Chem 7 because vomiting so much and metabolic alkalosis is common

Question 6

Imaging SBO

Answer 6

Abdominal X-ray: dilated bowel loops and air-fluid levels in step ladder pattern; point of transition
CT- contrast given has osmotic properties that may alleviate/treat the adhesive SBO

Question 7

Tx SBO

Answer 7

NPO
IVF
NG tube- decompress intestine
Surgery- done for all the other causes except adhesions and Crohn’s; if adhesion/Crohn give the patient 4 days on other tx before surgery

Question 8

Patho Ileus

Answer 8

• postoperative paralytic ileus

- non-mechanical insult disrupts the normal coordinated propulsive motor activity of the GI tract

Question 9

Clinical Ileus

Answer 9

• vomit
• abdomen distended
• not passing gas
• Xray/CT show the whole bowel is dilated without a transition pt

Question 10

Appendix anatomy

Answer 10

• located where the tenia joins at cecum
• intraperitoneal organ
• true diverticulum
• supplied by superior mesenteric artery

Question 11

Who gets appendicitis?

Answer 11

young people

Question 12

Patho appendicitis

Answer 12

Obstruction at lumen of appendix –> Stasis/stoppage of flow in GI–> bacteria stopped and replicate–> inflamation/swollen appendix–> artery unable to supply blood to appendix due to inflammation–> ischemia–> necrosis–> falls apart–> perforation–> bacteria leaks into stomach–> abscess risk and peritonitis–> RLQ pain

Question 13

MC organism in appendicitis

Answer 13

E. coli

Question 14

What can cause obstruction at the lumen of appendix?

Answer 14

• Fecaliths
• calculi
• lymphoid hyperplasia
• infection
• tumors

Question 15

Clinical appendicitis

Answer 15

• Crampy abdominal pain
• N/V
• low grade fever
• anorexia
• malaise

Question 16

Different physical tests for appendicitis

Answer 16

McBurney Point
Rovsing Sign
Psoas Sign
Obturator Sign

Question 17

Labs appendicitis

Answer 17

CBC with diff- leukocytosis
Low electrolytes (not eating/ drinking)
LFT
Urinalysis

Question 18

Imaging appendicitis

Answer 18

US- can ID appendix

CT- highest sensitivity/ specificity; not always necessary

Question 19

Tx appendicitis

Answer 19

NPO
IVF
IV ABX- broad spectrum
Surgery- appendectomy

Question 20

Def Toxic Megacolon

Answer 20

total or segmental non-obstructive colonic dilation plus systemic toxicity

Question 21

Causes Toxic Megacolon

Answer 21

IBD
Bacterial- c. diff, salmonella, shigela, campylobacter, yersinia
Parasitic- E. histolytica, Cryptosporidium
Viral- CMV

Question 22

Patho Toxic Megacolon

Answer 22

• Mucosal inflammation–> release of inflammatory mediators and bacterial products–> increased NO synthesis , antimotility agents–> colonic dilation
• severe inflammation –> paralysis of the colonic smooth muscle–> dilation

Question 23

Possible precipitating agents of toxic megacolon

Answer 23

hypokalemia, antimotility agents, opiates, anticholinergics, antidepressants, barium enema, colonoscopy

Question 24

Dx Essentials Toxic Megacolon

Answer 24

• abdominal distention and acute/chronic diarrhea
• radiographic evidence of colonic distention
• 3 of the following: fever over 38C, HR over 120, WBC over 10,500, anemia
• 1 of the following: dehydration, altered sensorium, electrolyte disturbances, hypotension

Question 25

Imaging Toxic Megacolon

Answer 25

Xray/CT- large colon inflamed

Question 26

Labs Toxic Megacolon

Answer 26

- Stool WBC and cultures if think infectious - CBC--> anemia - Chem 7

Question 27

Tx Toxic Megacolon

Answer 27

``` Non-operative (first line) - IVF - Correct lab abnormalities - ABX for IBD or infectious (Vanco+Flagy for cdiff) - intravenous corticosteroids (IBD) - NPO - Bowel decompression with NGT Surgery if no improvement - subtotal colectomy with end-ileostomy (50% mortality) ```

Question 28

Mesenteric ischemia

Answer 28

ischemia of the small bowel, usually secondary to an acute cause affecting SMA or SMV

Question 29

Ischemic colitis

Answer 29

ischemia of the colon with unknown precipitating factor

Question 30

Cause Mesenteric Ischemia

Answer 30

- SMA occlusion (embolism/thrombosis) - Nonocclusive Mesenteric Ischemia (atherosclerosis + shock + vasopressors) - Mesenteric Venous Thrombosis (primary clotting disroder)

Question 31

Clinical Ischemic Bowel Disorder

Answer 31

- rapid onset of severe, unrelenting periumbilical pain - patient is writhing on bed, screaming in agony but stomach is soft and normal - N/V - forceful/urgent bowel evacuation

Question 32

Test of choice for Ischemic Bowel Disease

Answer 32

mesenteric angiography; ID type of AMI and can treat them at that moment

Question 33

Imaging for Ischemic Bowel Disease

Answer 33

Xray- thumb printing on edge of bowel due to dilation, swelling, edema CT- thickened/dilated bowel, intramural hematoma, abdominal wall breaking down

Question 34

Tx for Ischemic Bowel Disease

Answer 34

- IVF - Anti-coag (IV heparin) - IV vasodilator (glucagon systemically or papverine through a catheter)

Question 35

When does patient need to be in the OR by for Ischemic Bowel Disease?

Answer 35

4-6hrs

Question 36

Clinical signs for Ischemic Bowel Disease to an infarct

Answer 36

- fever | - person is writhing around and all of a sudden they are pain free due to bowel dieing

Question 37

Tx for Ischemic Bowel Disease to an infarct

Answer 37

- emergent laporatomy- restoration of interrupted blood flow with arteriotomy/ bypass graft and resection of infarcted bowel - look again 24-48hrs later to see if alive or dead bowel - need vasodilators

Question 38

What is chronic mesenteric?

Answer 38

intestinal angina

Question 39

When does chronic mesenteric occur?

Answer 39

after meals patient gets extremely crampy--> food fears due to this--> weight loss

Question 40

What causes chronic mesenteric?

Answer 40

atherosclerosis

Question 41

What is the most frequent form of mesenteric ischemia?

Answer 41

colonic ischemia

Question 42

Where does colonic ischemia occur?

Answer 42

left colon

Question 43

Who is most likely to get colonic ischemia and why?

Answer 43

elderly due to atherosclerotic disease

Question 44

Cause of colonic ischemia

Answer 44

- Low- flow state (hypotension) - embolus (afib) - Post MI - Post AAA reconstruction - Closed loop construction - volvulus - mesenteric vein thrombosus

Question 45

What are the watershed areas?

Answer 45

- rectosigmoid junction - left colon (splenic flexture) - runoff from SMA to IMA vessels

Question 46

What is a watershed area?

Answer 46

- regions of the body that receive dual blood supply from the most distal branches of two large arteries - during hypoperfusion, these regions are particularly vulnerable to ischemia because they are supplied by the most distal branches of their arteries, and the least likely to receive sufficient blood

Question 47

Clinical colonic ischemia

Answer 47

- crampy and tender abdominal pain - nausea - vomiting - bloody diarrhea - blood per rectum

Question 48

Dx colonic ischemia

Answer 48

H/PE mainly Lab- rule out other diseases (metabolic acidosis and elevated white count over 20K) Imaging - CT- normal at first but then thickened bowel wall in segmental pattern and mesenteric stranding; later gas in mesenteric veins and pneumatosis - Endoscopy- mucosa red and sloughing off and ulcers

Question 49

Tx colonic ischemia

Answer 49

``` Support -IVF - NPO - Empiric ABX for moderate/severe - NGT - no meds that promote ischemia - optimize cardiac and pulmonary functions Surgery - laparotomy with resection if clinical deterioration despite support - patient will receive colostomy bag ```