What is mesenteric ischemia?
The
mesenteric arteries are the arteries that supply blood to your large and small
intestines. Ischemia occurs when your blood cannot flow through your arteries as
well as it should, and your intestines do not receive the necessary oxygen to
perform normally.
Mesenteric ischemia usually involves the small intestine.
Mesenteric ischemia usually occurs when one or more of your mesenteric
arteries narrows or becomes blocked. When this blockage occurs, you can
experience severe abdominal pain. Over time, often quickly, the blockage may
worsen and cause tissues in your intestine to die because they lack enough blood
flow.
Mesenteric ischemia usually occurs in people older than age 60. You may be
more likely to experience mesenteric ischemia if you are a smoker or have a high
cholesterol level. Mesenteric ischemia can be either chronic or acute. Chronic
means that you have had the condition and symptoms over a relatively long period
of time. Acute means that the symptoms start abruptly and become very serious in
a short period of time. Chronic mesenteric ischemia can progress without warning
to acute mesenteric ischemia, sometimes very quickly.
What are
the symptoms?
If you have chronic mesenteric ischemia, you may
experience severe pain in your abdomen 15 to 60 minutes after you eat. This pain
can occur in any part of the abdomen, but most commonly it occurs in the middle
to upper part. The pain may last for as long as 60 to 90 minutes and then
disappear. Unfortunately, it tends to return the next time you eat. Many people
with chronic mesenteric ischemia begin losing weight because, although they may
feel hungry, they do not want to eat because they experience the
pain.
Sometimes the symptoms of chronic mesenteric ischemia can be vague and
can be similar to those of other conditions. Therefore, your physician will
evaluate you and order tests to rule out other problems before making a definite
diagnosis. In addition to abdominal pain and weight loss, other symptoms that
you might experience include:
• Diarrhea
• Nausea
• Vomiting
• Flatulence
• Constipation
With acute mesenteric ischemia, you may have sudden, severe stomach pain.
Narcotic pain medications may not adequately alleviate the pain that is
associated with mesenteric ischemia. With acute mesenteric ischemia, you may
also experience nausea or vomiting.
What causes mesenteric ischemia?
Atherosclerosis, which
slows the amount blood flowing through your arteries, is a frequent cause of
chronic mesenteric ischemia. Your arteries are normally smooth and unobstructed
on the inside, but as you age, a sticky substance called plaque forms in the
walls of your arteries. Plaque is made of fats and other materials circulating
in your blood. As more plaque builds up, your arteries can narrow and stiffen.
Eventually, enough plaque builds up to reduce blood flow through your
arteries.
A clot, called an embolus, which travels to one of the mesenteric arteries
and suddenly blocks the blood flow, is a common cause for acute mesenteric
ischemia. These clots often originate in the heart and are more common among
patients with an irregular heartbeat or heart disease.
Other conditions that may lead to mesenteric ischemia include:
• Low
blood pressure
• Congestive heart failure
• Aortic dissection,
which is a tear in the aorta's inner layer; or
• Occlusion or blockage
of the veins in the bowel, or
• Coagulation disorders
Mesenteric ischemia is a serious condition that may come on and worsen
quickly. It is extremely important that you go to your physician or the
emergency room if you experience any of the symptoms.
What tests will I need?
Your physician may perform
several tests to rule out other conditions with similar symptoms. First your
physician will ask you questions about your general health, medical history, and
symptoms. In addition, your physician will conduct a physical examination.
Together these are known as a patient history and exam. As part of your history
and exam, your physician will ask you if you smoke or have high blood pressure.
Your physician will also want to know when and how often your symptoms occur as
well as how long you have been experiencing them.
After the history and exam, if your physician suspects you may have chronic
or acute mesenteric ischemia, he or she may perform additional tests to evaluate
your bowel and circulation, such as:
• Angiogram: An angiogram (also called an
arteriogram) is the test of choice, especially for acute mesenteric ischemia
when rapid diagnosis is very important. An angiogram uses x-rays to view your
body’s blood vessels. When the arteries are studied, the test is also called
an arteriogram. To create the x-ray images, your physician will inject a dye
through a thin, flexible tube, called a catheter, which is threaded into the
desired artery from an access point. The access point is usually in your groin
but it can also be in your arm. This dye, called contrast, makes blood vessels
visible on an x-ray. In some circumstances, treatment through the catheter may
also be started at the time of the angiogram
• Doppler
Ultrasound. Doppler ultrasound uses high-frequency sound waves that
bounce off of blood cells and blood vessels. This test can determine blood
flow and show problems with the structure of blood vessels while it identifies
specific arteries that are blocked. It takes some time to perform, however,
and its accuracy may be limited by gas in the bowel.
• Blood
test. When you have mesenteric ischemia, especially the acute
variety, your white blood cells may be high. Blood tests may also show if acid
in your blood is at high levels, a condition called acidosis. These findings
may indicate the presence of serious bowel injury.
• Computerized Tomography (CT Scan): A CT scan
creates detailed three-dimensional images from x-rays of slices of your body
and can determine if there are problems with the arteries, such as aortic
dissection, as well as with your other abdominal organs.
• Magnetic Resonance Angiogram(MRA)Scan: MRA scan
also creates detailed three-dimensional images of your blood vessels from
magnetic images of slices of your body. Its use is limited, however, if you
have a metal implant in your body, such as a pacemaker or artificial hip.
How is a mesenteric ischemia treated?
The goal of
treatment for mesenteric ischemia (both chronic and acute) is to re-open the
artery to allow adequate blood flow to reach your intestine to allow it to work
properly. Because this must be accomplished before permanent damage is done to
the bowel, depending on the situation, your vascular surgeon may treat
mesenteric ischemia as an emergency or as a scheduled procedure.
For chronic mesenteric ischemia, one treatment method
is trans-aortic endarterectomy, which is an operation that removes the plaque that
blocks your mesenteric artery. To perform this procedure, a vascular surgeon
makes an incision in your abdomen, or side, and then removes the plaque contained
in the inner lining of the blocked mesenteric artery. Another treatment
option for chronic mesenteric ischemia is bypass surgery. In bypass surgery,
the surgeon creates a detour around a narrowed or blocked section of the artery.
To create this bypass, your vascular specialist can use one of your veins or sometimes a
tube made from man-made materials can be used as an alternative. Your
vascular specialist attaches the bypass above and below the blocked area, producing a new
path for blood to flow to your intestines. Your vascular surgeon will advise you
what procedure is best for you on the basis of your particular situation.
Angioplasty and stenting is a newer method for opening a mesenteric artery
and bracing it open to allow the blood to flow through. It can sometimes be
performed at the time of the angiogram. In an angioplasty procedure, your
vascular surgeon inflates a small balloon inside a narrowed mesenteric artery.
After widening the artery with angioplasty, your vascular surgeon may insert a
stent, which is a tiny metallic mesh tube that can support your artery’s walls
to keep your vessel wide open.
Treatment for acute mesenteric ischemia is usually an emergency procedure,
since severe intestinal damage can occur rapidly in this setting. Your physician
may use medications, called thrombolytic agents, to dissolve a clot, if one is
found soon enough. To perform this treatment, your physician injects
clot-dissolving medications into a blood vessel, often at the time of the
angiogram. In some cases, the medications flow through your bloodstream to the
clot and can disintegrate the clot. However, your vascular surgeon may need to
remove the clot surgically, especially if there is evidence of intestinal damage
or too little time is available for the thrombolytic agent to work.
Since the effectiveness, risk, and durability of each tool available for the
treatment of mesenteric ischemia depends upon many issues, your vascular surgeon
will advise you as to what procedure is the best for your particular situation.
With acute mesenteric ischemia, you may have sudden, severe stomach pain.
Narcotic pain medications may not adequately alleviate the pain that is
associated with mesenteric ischemia. With acute mesenteric ischemia, you may
also experience nausea or vomiting.
For more information about the treatment of mesenteric
ischemia, call LifeBridge Health at 410-601-WELL (9355).
