78. Small intestine Flashcards
Types of mechanical SBO
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
Simple vs closed loop obstruction
simple: single point
closed loop: at two locations so issues prox and distal
Types of SBO other than mechanical?
neurogenic
functional
ileus, pseudoosbtruction: degen neuropathies, autoimmune, paraneoplastic disease: SLE, scleroderma, herediatry
DDX 4 external to intestinal wall SBO
postop adhesion
hernia
volvulus
masses
DDX 7 intrinsic to intestinal wall SBO
primary neoplasm
inflamm: crohn’s, radiation
infectious - TB
intuss
trauma: hematoma
intraluminal: bezoar, fb, gallstone, ascaris
Causes of adynamic ileus - name 5
metabolic disease (hypok)
meds: narcotics
infection: retroperitoneal, pelvic, intrathoracic
abdo trauma
lap
How does a SBO cause issues?
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
What is a particular complication of a closed loop obstruction?
strangulation due to venous congestio and arterial congestion from rapid incr pressure
–> can lead to necrosis and perf
MC cause SBO?
adhesions
2nd = tumor
What tumors can cause SBO? List 5
adenocarcinoma
carcinoid
lymphoma
sarcoma
adenoma
lipoma
mets
ovarian ca
Intussuception causes child vs adult
child - idio, adenovirus
adult: tumor, aids secondary to lymphoma, infection
What imaging for SBO?
upright AXR - r/o perf, also may see distended loops of bowel >3cm central
but really ct w/ IV contrast best gold standard
Valvuale convientes of Small bowel ? cross or not?
cross!
haustra of large bowel do not cross
adynamic ileus findings on imaging:
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
Management of SBO:
- IVF and antinausea meds, pain
- If hernia, reduce
- NG decompression to low gomco
- surg consult
Suspected perf SBO - abx?
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).
Complications of SBO
metabolic alkalosis
shock
stranulation
hypovolemia
perforation
abscess
Acute mesenteric ischemia: what is this?
sudden reduction or loss of blood flow to small bowel and possibly right colon
Acute mesenteric ischemia: which side often more involved?
R - L has more collaterals
Celiac trunk supplies what small intestine section?
distal eesophagus to dudodenum at entrance to bile duct
SMA supplies what small intestine section?
distal half dudd to proximal 2/3 transverse colon
IMA supplies what small intestine section?
distal 1/3 transverse colon to rectum
2 main mechanisms of blood flow in small intestine?
metabolic
myogenic
Diagnosis of acute mesenteric ischemia: 4 clinical entities that may cause this?
mes arterial embolism
mes arterial thrombosis
nonocclusive mes ischemia
mes venous thrombus
Mes embolism causes
LA/ventricular thrombi/valvular lesions
RF - MI, cardiomyopathy, vent aneurysm, endocarditis, atrial dysr **afib **SMA mc effected
Mes VTE mc causes - list 8
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
Mes VTE mc causes - 4 big categories
- hypercoagulable states
- inflamm conditions
- trauma
- miscellanous: HF, renal failure, decompression sickness, portal HTN
PE and diagnsotics of acute mesenteric ischemia:
pain out of proportion
soft abdo –> peritonitis
signs of SIRS
+++ lactate + CTA
Management of acute mesenteric ischemia:
- IVF and HD stability
- heparin anticoag unless CI
- vp - consider dobutamin/milironine as less vasoconstr effect
- evidence of infarct, peritonitis or perf: ceftr or cipro with metronidazole or piptazo or carbapenem
- surgery or EVT if arterial clot vs heparin and consideration of fibrinolysis
Obtuator hernia: who is at risk?
older wo
sign w loss due to wide pelvis and obturator canal wide in wo
Roux-en y surgery has what type of sbo causing recognized complication?
internal hernias - prompt surgery, ct
What is the length of time from acute ischemia of the intestines to completion of transmural necrosis?
6hr
