78. Small intestine

Question 1

Types of mechanical SBO

Answer 1

physical barrier to movement - cause relative to intestinal wall
a. External: obstruction by compression like adhesions, hernia, neoplasm
b. iNtrinsic: primary intestinal neoplasm, infection, btrauma
c. intrinsic lumen: bezoars, FB, gallstone

Question 2

Simple vs closed loop obstruction

Answer 2

simple: single point
closed loop: at two locations so issues prox and distal

Question 3

Types of SBO other than mechanical?

Answer 3

neurogenic
functional

ileus, pseudoosbtruction: degen neuropathies, autoimmune, paraneoplastic disease: SLE, scleroderma, herediatry

Question 4

DDX 4 external to intestinal wall SBO

Answer 4

postop adhesion
hernia
volvulus
masses

Question 5

DDX 7 intrinsic to intestinal wall SBO

Answer 5

primary neoplasm
inflamm: crohn’s, radiation
infectious - TB
intuss
trauma: hematoma
intraluminal: bezoar, fb, gallstone, ascaris

Question 6

Causes of adynamic ileus - name 5

Answer 6

metabolic disease (hypok)
meds: narcotics
infection: retroperitoneal, pelvic, intrathoracic
abdo trauma
lap

Question 7

How does a SBO cause issues?

Answer 7

interruption normal flow - secreations can accumulate to dilate further attempts at peristalsis down the way
bowel wall becomes edematous
bacterial overgwoth then possible and fluid loss into cavity

Question 8

What is a particular complication of a closed loop obstruction?

Answer 8

strangulation due to venous congestio and arterial congestion from rapid incr pressure
–> can lead to necrosis and perf

Question 9

MC cause SBO?

Answer 9

adhesions
2nd = tumor

Question 10

What tumors can cause SBO? List 5

Answer 10

adenocarcinoma
carcinoid
lymphoma
sarcoma
adenoma
lipoma
mets
ovarian ca

Question 11

Intussuception causes child vs adult

Answer 11

child - idio, adenovirus
adult: tumor, aids secondary to lymphoma, infection

Question 12

What imaging for SBO?

Answer 12

upright AXR - r/o perf, also may see distended loops of bowel >3cm central

but really ct w/ IV contrast best gold standard

Question 13

Valvuale convientes of Small bowel ? cross or not?

Answer 13

cross!
haustra of large bowel do not cross

Question 14

adynamic ileus findings on imaging:

Answer 14

An adynamic ileus, on the other hand, tends to show extensive air-filled loops throughout the entirety of the GI tract without small bowel dilation

Question 15

Management of SBO:

Answer 15

1. IVF and antinausea meds, pain
2. If hernia, reduce
3. NG decompression to low gomco
4. surg consult

Question 16

Suspected perf SBO - abx?

Answer 16

either a third-generation cephalosporin such as ceftriaxone 2 g IV daily or a fluoroquinolone such as ciprofloxacin 400 mg IV q12 hours, either combined with metronidazole 500 mg IV q8 hours. Single drug broad-spectrum options include piperacillin-tazobactam 3.375 g IV q6 hours or a carbapenem such as meropenem, 1000 mg IV tid).

Question 17

Complications of SBO

Answer 17

metabolic alkalosis
shock
stranulation
hypovolemia
perforation
abscess

Question 18

Acute mesenteric ischemia: what is this?

Answer 18

sudden reduction or loss of blood flow to small bowel and possibly right colon

Question 19

Acute mesenteric ischemia: which side often more involved?

Answer 19

R - L has more collaterals

Question 20

Celiac trunk supplies what small intestine section?

Answer 20

distal eesophagus to dudodenum at entrance to bile duct

Question 21

SMA supplies what small intestine section?

Answer 21

distal half dudd to proximal 2/3 transverse colon

Question 22

IMA supplies what small intestine section?

Answer 22

distal 1/3 transverse colon to rectum

Question 23

2 main mechanisms of blood flow in small intestine?

Answer 23

metabolic
myogenic

Question 24

Diagnosis of acute mesenteric ischemia: 4 clinical entities that may cause this?

Answer 24

mes arterial embolism
mes arterial thrombosis
nonocclusive mes ischemia
mes venous thrombus

Question 25

Mes embolism causes

Answer 25

LA/ventricular thrombi/valvular lesions
RF - MI, cardiomyopathy, vent aneurysm, endocarditis, atrial dysr **afib **SMA mc effected

Question 26

Mes VTE mc causes - list 8

Answer 26

hereditary like factor V leiden
defic antithrombin c, s
local inflamm: pancreatitis, malignancy, inflamm bowel disorder
scd
e2 therapy
op venous injury
hg
portal HTN

Question 27

Mes VTE mc causes - 4 big categories

Answer 27

1. hypercoagulable states
2. inflamm conditions
3. trauma
4. miscellanous: HF, renal failure, decompression sickness, portal HTN

Question 28

PE and diagnsotics of acute mesenteric ischemia:

Answer 28

pain out of proportion
soft abdo –> peritonitis
signs of SIRS

+++ lactate + CTA

Question 29

Management of acute mesenteric ischemia:

Answer 29

1. IVF and HD stability
2. heparin anticoag unless CI
3. vp - consider dobutamin/milironine as less vasoconstr effect
4. evidence of infarct, peritonitis or perf: ceftr or cipro with metronidazole or piptazo or carbapenem
5. surgery or EVT if arterial clot vs heparin and consideration of fibrinolysis

Question 30

Obtuator hernia: who is at risk?

Answer 30

older wo
sign w loss due to wide pelvis and obturator canal wide in wo

Question 31

Roux-en y surgery has what type of sbo causing recognized complication?

Answer 31

internal hernias - prompt surgery, ct

Question 32

What is the length of time from acute ischemia of the intestines to completion of transmural necrosis?

Answer 32

6hr