Intestinal obstruction

Question 1

caused by decreased intestinal blood flow causing ischemia and subsequent reperfusion damage that may progress to mucosal injury, tissue necrosis & metabolic acidosis

Answer 1

mesenteric ischemia

Question 2

3 major GI arteries off the abdominal aorta

Answer 2

celiac axis
SMA
IMA

Question 3

3 primary causes of mesenteric ischemia

Answer 3

arterial embolism
arterial thrombosis– in those w preexisting mesenteric artherosclerosis
non-occlusive etiology– severe systemic illness w/ systemic shock usually d/t reduced CO (hypovolemia)

Question 4

symptoms include

• severe, poorly localized, post-prandial abdominal pain w/ sorta normal abdomnial exam
• not really relieved w/ opiods
• N/V/D common
• if chronic– wt loss & sitophobia
• later dz– distention, ileus, melena, hematochezia

Answer 4

mesenteric ischemia

Question 5

how to revascularize a mesenteric ischemia caused by embolism vs thrombosis vs venous thrombosis if WITHOUT peritoneal signs?

Answer 5

• embolsim– early laparotomy w/ embolectomy
• arterial thrombosis– bypass graft or basloon dilation angioplasty w/ stenting
• venous thrombosis– systemic anticoag (heparin, warfarin)

Question 6

if there are peritoneal signs or signs of perforation or gangrene, how are acute mesenteric ischemias treated?

Answer 6

emergent surgical exploration via laparotomy (after stabilization) to restore flow & resect nonviable bowel

Question 7

• transient impaired persistalsis in intestine causing gas & fluid accumulation in bowel
• # 1 cause is post-op
• typically resolves in 2-3 days; if longer then its post-op ileus

Answer 7

ileus (functional)

Question 8

this is the pathophys of ileus

• activation of inhibitory spinal reflex arcs– what prevents?
• [insert word] stress generates endocrine & inflammatory mediators (promotes)

Answer 8

• spinal epidural prevents
• surgical stress promotes

Question 9

other causes of post-op ileus

Answer 9

somatic & visceral trauma activating mast cells, etc
gut handling & anastomosis interferes w/ electromechanical coupling
fluid overload/ electrolyte abnormalities
opioid analgesia decreases motliti

Question 10

• slower onset of vague mild abd pain & bloating; N/V poor appetite; obstipation
• NO CRAMPING
• distended abdomen w/ tympany and decreased or no bowel sounds

Answer 10

ileus

Question 11

expected imaging for ileus on plain film

Answer 11

nonspecific bowel gas pattern; increased gas

Question 12

how can contrast help r/o mechanical SBO?

Answer 12

if the contrast does not reach cecum in 4 hrs then r/o mechanical SBO

Question 13

how is ileus managed? (4)

Answer 13

• Admit for watchful waiting & hydration
• correct underlying cause
• +/- NGT; NPO till resolved; gum chewing?
• d/c meds (opiates)

Question 14

general cause of FUNCTIONAL SBO

Answer 14

bowel wall or splanchnic nerve dysfunction

Question 15

are adnesions, hernias, volulus aand neoplasms luminal, mural or extraluminal?

Answer 15

all are extraluminal except neoplasms which are mural

Question 16

differentiate close vs open ended SBO in terms of movement. Which is typically luminal?

Answer 16

• closed has 2 points and prevents any movement of contents; can affect blood supply
• open has one point and affects with prograde movement; typically luminal

Question 17

whats a complicated obstruction?

Answer 17

affects circulation with resultant ischemia, infarction and perforation

Question 18

what are the 3 specific mechanical obstructions in SBO that we talked about

Answer 18

intussception
volvuus
gallstone ileus

Question 19

invagination of segment of bowel into another causing triad of vomiting + abdominal pain + blood per rectum (currant jelly stools) in kids esp after viral infection

Answer 19

intussception

Question 20

axial twist of segment around its mesentery → closed loop obstruction and variable degree of vessel obstruction

Answer 20

volvulus

Question 21

pathophys of SBO; fill in the blank

• obstruction causes progressive dilation of the intestine ____ to blockage while ____ to the blockage, it’ll decompress as luminal contents pass
• air swallowed & bacterial fermentation cause gas accumulation

Answer 21

1st space: Proximal
2nd space: distal

Question 22

most common cause for SBO

Answer 22

adhesions

Question 23

distal vs proximal distention– which is more associated w/ vomiting? which is more associated with distention?

Answer 23

• Proximal SBO: acute colicky pain with bilious vomiting
• distal SBO: progressive with distention (distal-distention)

Question 24

PE of distention, hyperactive high-pitched BS (early), hypoactive BS later, fever, tachycardia, TTP

Answer 24

SBO

Question 25

what is the uright XR finding for SBO? when do you get a CT?

Answer 25

plain film-- increased air or multi-height air fluid level (flat straight lines ladder) CT if patient has fever, tachycardia, leukocytosis, or localized abd pain

Question 26

how is SBO managed?

Answer 26

* ADMIT * aggressive fluid resus * analgesia and antiemetic tx PRN * NGT (aka bowel decompression) * early surgical consult * abx prophylaxis * NPO * ambulation and close observatoin

Question 27

# what is this? how is it treated? * happens when inflammation & adhesions after cholecystitis causes choleocystenetic fistula via which gallstones enter the bowel and goes to either stomach or down the SB. * makes up a quarter of the nonstrangulating SBO in over 65yo; * most happen at the terminal ileus

Answer 27

gallstone ileus surgically corrected

Question 28

functional obstruction causing massive acute colonic dilation in absence of any mechanical obstruction, usually at the cecum or right hemicolon with mortality rate of 40%

Answer 28

acute colonic pseudo-obstruction (Ogilvie's Syndrome)

Question 29

explain laplace's law & which condition it's the most relevant to. What are 4 things it could cause?

Answer 29

* the intraluminal pressure needed to stretch the wall of a hollow tube & the diameter of that same tube are inversely related * most relevant to Ogilvie's syndrome * implications-- ischemia, serosal splitting, herniation, perforation

Question 30

3 etiologies of ogilvie's syndrome

Answer 30

retroperitoneal trauma serious infection cardiac dz (MI or CHF)

Question 31

most common presentation of ogilvie's syndrome

Answer 31

**debilitated**, **hospitalized** patient w/ **multiple medical problems** and **history of many surgical conditions.**

Question 32

what do you need to diagnose ogilvies? (3)

Answer 32

signs & sx; history CBC, CMP plain films of adomen

Question 33

first thing to do when managing ogilvies

Answer 33

r/o mechanical obstruction! - need to see colonic air in all segments; if not visible, get barium enema! - aggressive management of underlying issues & stop narcotics

Question 34

how is < 9 cm cecum ogilvie's managed? give 4 examples

Answer 34

conservatively - prevent consipation - NPO, decompression, correct lytes, tx infection, etc

Question 35

if conservative tx isn't working what are 3 ways to treat ogilvies?

Answer 35

1. sympathetic blocker (ocretotide) then cholinesterase inhibitor (neostigmine) 2. colonsocopic decompression to reduce perforation risk 3. surgery for perforations or mechanical obstructive risk

Question 36

# what is the condition? radiological finding: marked isolated large bowel dilation (likely R side), diaphragm elevated

Answer 36

ogilvie's

Question 36

# what is the condition? radiological finding: marked isolated large bowel dilation (likely R side), diaphragm elevated

Answer 36

ogilvie's

Question 37

PE findings with ogilvie's is most similar to what other condition?

Answer 37

SBO

Question 38

if patient with sx of SBO is not clinically stable what do you do? if they are stable then what?

Answer 38

* unstable-- laparotomy * stable-- XR or CT

Question 39

if person w/ sx of SBO shows signs of vascular compromise or perforation on imaging, what next? what if it shows complete or partial obstruction instead?

Answer 39

* vascular comp or perf-- laparotomy * any obstruction-- NPO, NGT, IV fluids

Question 40

what happens if person with partial obstruction doesn't resolve in 1-2 days? what if its complete that doesnt resolve?

Answer 40

* unresolving partial-- upper GI/SB follow-thru or enteroclysis (if it doesnt resolve then laparotomy) * unresolving complete-- laparotomy

Question 41

which lab is essential in SB infarction or acute mesenteric ischemia?

Answer 41

**lactate/lactic acid** (NOT LDH)

Question 42

most common, but still rare neuroendocrine tumors from enterochromaffin cells that mostly happen in GI tract of kids; tend to be incidental findings

Answer 42

carcinoid tumor

Question 43

what is the classic carcinoid traid?

Answer 43

**diarrhea, flushing & wheezing respiration** (also **PERIODIC abd. pain**, tachycardia, hypotension)

Question 44

best screening test for carcinoid tumors? how is it treated?

Answer 44

screen: 24hr urinary 5-HIAA treatment: surgery, chemo for carcinoid syndrome