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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