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Ischemia bowel
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Ischemia bowel
"Occlusion of the mesenteric vessels is
apt to be regarded as one of thoseconditions of which the diagnosis is
impossible, the prognosis hopeless, and
the treatment almost useless" (Cokkinis,1926).
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Ischemia bowel
inadequate blood flow to or from the
involved mesenteric vessels supplying aparticular segment of bowel.
The organs typically affected are the small
bowel or colon.
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Ischemia bowel
Patients with inflammatory bowel disease and infectious
colitis can present with similar s/s: cramping
abdominal pain, diarrhea, leukocytosis, andhematochezia. Bowel-wall thickening.
however, the pattern of vascular distribution
can sometimes narrow the differential diagnosis.
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Ischemia bowel
acuteor chronic.
arterialor venous
occlusiveornonocclusive.
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Pathophysiology
Arterial sources v.s. venous sources:
proximately 9:1. Similarly, arterialocclusive disease occurs more frequentlythan nonocclusive disease approximately9:1
The SMA and IMA, and their branches,are more frequently than the celiac artery.
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Pathophysiology (a. source)
Acute:
1.atheromatous plaque with intimal
calcifications2.embolic from cardiac disease
3. abdominal aortic aneurysms with dissection
into SMA4. hypoperfusion secondary to hypovolemic
shock or low-flow cardiac failure.
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Pathophysiology (a. source)
Chronic :
1.atherosclerosis
2.fibromuscular dysplasia
3.vasculitis.
Both occlusive and nonocclusive subtypes can
occur .
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Pathophysiology (v. source)
are less frequently.
In these cases, bowel ischemia results from
decreased mesenteric outflow ofdeoxygenated blood rather than fromdecreased perfusion of oxygen-rich blood
Mortality rates generally are low. SMV is involved more often than the IMV.
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Pathophysiology (v. source)
The particular cause often is not clear.
Predisposing risk factors :
1. thrombosis
2. recent abdominal surgery
3. infection4. hypercoagulable states.
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Pathophysiology
Additional rare causes of mesenteric ischemiainclude :
1.bowel herniation
2. adhesions
3. intussusception
4. antiphospholipid antibody syndrome (APS).
APS is associated with hypercoagulable states secondary to circulatingimmunoglobulins that interact with phospholipids in cell membranes.
In a recent study by Kaushik et al, 13 (31%)of 42 patients with APS hadCT findings of bowel ischemia.
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Acute Ischemia bowel
is divided into:
1.Embolic acute mesenteric ischemia
2.thrombolic acute mesenteric ischemia
3. NOMI
4. mesenteric venous thrombosis
all types of AMI share many similarities and a finalcommon pathway ( bowel infarction and death, if notproperly treated),they are discussed together
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1.Embolic acute mesenteric
ischemia has the most abrupt and painful presentation of
all types. abdominal apoplexy.
initial :soft , no tenderness,
vomiting and diarrhea (gut emptying) are observed.
most emboli are of cardiac origin( atrial fibrillationor a recent MI . a history of valvular heart disease orprevious embolic episode.)
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2.Thrombotic acute mesenteric ischemia
(TAMI)
happens when an artery already partially
blocked by atherosclerosis becomes completely
occluded.
20-50% of these patients have a history ofabdominal angina.( postprandial abdominal pain
starting soon after eating and lasting for up to 3
hours.)
Weight loss, food fear ,early satiety, and altered
bowel habits may be present
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2.Thrombotic acute mesenteric ischemia
(TAMI)
The precipitating event :
1. a sudden drop in C.O. ( MI or CHF or aruptured plaque). 2.Dehydration.
gradual progression and frequently have abetter collateral supply. Bowel viability is betterpreserved.
Symptoms tend to be less intense and of moregradual onset.
have a history of atherosclerotic disease atother sites or a history of aortic reconstruction
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3.Nonocclusive mesenteric
ischemia more frequently in older patients than other
forms and often already in an ICU setting .
Symptoms typically develop over several days,
and may have had a prodrome of malaise and
vague abdominal discomfort.
When infarction occurs, increased painassociated with vomiting,hypotensive and
tachycardic, with loose bloody stool.
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4.Mesenteric venous thrombosis
in a much younger patient population than other types .
acute or subacute abdominal pain involvement of thesmall intestine rather than the colon.
The symptoms are frequently less dramatic. 27%have symptoms for >30 d.
Many patients have a history of the risk factors forhypercoagulability. include oral contraceptive use,deep vein thrombosis (DVT), liver disease, tumor, orportocaval surgery.
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Pathophysiology
Large or smaller segments : depending on
the location of the occlusion.
mucosal layer becomes anoxic, cellfragility and irreversible cell death. Then,
the patient experiences malabsorption,
which causes diarrhea and rectal bleeding
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Mortality/Morbidity
The major cause of mortality is bowel
necrosis
Mortality from all causes is as high as 70%.However, several factors (particularly, the
adequacy of collateral vessels) account for
variability in mortality rates.
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Ischemia bowel
Race: No race predilection is known.
Sex: No sex predilection is known.
Age: Most patients are older than 50
years. Venous causes tend to affect a
wider range of patients.
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Clinical Details(acute)
Symptoms are usually nonspecific( D / D with diverticulitis, appendicitis, Crohn
disease, peptic ulcer disease, or pelvicinflammatory disease.)
typical : presents with acute abdominalpain ( initially is characterized as crampingpain, followed by a continuous dull pain. )
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Clinical Details (acute)
depending on the particular segment
involved, the pain may be morelocalized
to one side of the abdomen. SMA : tends to be more diffuse
IMA: Ischemic pain toward the left side
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Clinical Details(acute)
As ischemia progresses, bloody diarrhea,
gross bleeding per rectum, and/or
leukocytosis are delayed manifestations
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Clinical Details (chronic)
postprandial abdominal pain, typically
within several minutes of a meal.
reluctant to eat, similar to patients withpeptic ulcer disease.
weight loss and chronic diarrhea from
malabsorption.
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Preferred Examination
history and a physical examination ,
particularly :
1. the timing of the event. 2.localizingsigns and symptoms 3.vascular
distribution of the pain.
Unless the patient is unstable, imaging isthe criterion standard for diagnosis.
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Preferred Examination
1. Upright and supine plain abdominalradiographs:
should be requested first to evaluate for
free air, obstruction, ileus, intussusception, orvolvulus.
2. CTby using oral and, preferably,intravenous contrast:
may be needed if the cause is not
apparent on plain radiographs.
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Mesenteric artery ischemia. Radiograph showing bowel spasm, an early sign of
ischemia
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Mesenteric artery ischemia. Gas in the colon wall, typical of advanced ischemia.
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Preferred Examination
3.Sonography, barium enema study, and
angiography:
Typically, if additional imaging are needed, ultrasound orangiography is the next step in the workup.
MRA is occasionally used to evaluate the patency
of the SMA and IMA. It plays a limited role in the
diagnosis.
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Differential
AppendicitisTrauma
Pseudomembranous colitisAdenocarcinoma
DiverticulitisCrohn Disease
Necrotizing EnterocolitisPneumatosis Intestinalis
Typhlitis
Ulcerative Colitis
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Treatment:
NPO :prepare for surgery and to reduce oxygen
demand on the ischemic bowel
surgery
Interventional radiology: angiographic druginfusions or angioplasty.
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Treatment:
. acute occlusive mesenteric ischemia :
usually surgical resection of the infarctedbowel segment.
Chronic mesenteric ischemia :
not a surgical emergency and may be treatedconservatively.
Nonocclusive mesenteric ischemia :usually nonsurgically. Depending on the cause
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Complications:
Bowel necrosis (requiring bowel resection)
Septic shock
Death
Patients in whom the diagnosis is missed until infarctionoccurs have a mortality rate of 90%. Even with goodtreatment, up to 50-80% of patients die.
Survivors of extensive bowel resection face lifelongdisability.
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Take home message:
Hx: High risk patient ( Af hx, old age,
hypercoagulation state)
PE: Localized pain
Lab: CBC/DC, BCS+e, ABG,amylase ,lipase Image (Angiography:)
:.infarction
: Tx: NPO,antibiotics, fluid +electrolite correction,
surgery or intervention..
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Thank you for your attention