Mesenteric ischemia

Acute mesenteric ischemia manifests itself as severe abdominal pain with a sudden onset. It is life-threatening and must be treated by us immediately. We try to open the blocked vessel and restore blood flow. The chronic form, on the other hand, progresses slowly and insidiously. It often manifests itself as pain or discomfort after eating and with weight loss.

What is mesenteric ischemia?

Mesenteric ischemia is a circulatory disorder of the intestine caused by an obstruction or narrowing of the intestinal vessels. The intestinal vessels supply the intestines and other abdominal organs with blood, oxygen and nutrients. They are also called visceral arteries or mesenteric vessels. The word “ischemia” means “reduced blood flow”.

If an intestinal vessel closes completely, doctors speak of an intestinal infarction or a “mesenteric infarction” – similar to a heart attack, in which one or more coronary vessels close, or a cerebral infarction, in which vessels in the brain are blocked.

Mesenteric ischemia: acute or chronic

There are two types of mesenteric ischemia: it can be acute or chronic. Acute mesenteric ischemia is an emergency that we must treat immediately. Acute vascular occlusion is life-threatening, as the blood and oxygen supply to the intestine and other organs (e.g. stomach, liver) in the abdominal cavity is no longer guaranteed. Vascular occlusion of the intestinal vessels leads to the death of the intestine or other abdominal organs. Which organ is affected depends on the location of the vascular occlusion.

The most common cause of acute mesenteric ischemia is a blood clot (thrombus) that occludes an intestinal vessel. Either the blood clot forms directly in the intestinal vessel or it detaches from another part of the body and is carried with the bloodstream towards the intestinal vessels. The blood clot often originally forms in the heart, for example in the case of cardiac arrhythmia, a heart attack or diseases of the heart valves.

In chronic mesenteric ischemia, however, the narrowing of the intestinal vessels develops slowly and insidiously – the blood vessels become increasingly “calcified” and constrict. This process is called arteriosclerosis and can occur in all the body’s blood vessels with increasing age.

The symptoms of acute mesenteric ischemia are sudden, severe abdominal pain, nausea, vomiting and diarrhea. It is fatal that the symptoms improve again after a few hours, but the illness is by no means over – on the contrary. Without treatment, it ends fatally. The therapy consists of reopening the blocked intestinal vessel as quickly as possible or creating a bypass and thus restoring blood flow. This is always done as part of an operation, and the bowel and other abdominal organs should also be assessed.

Chronic mesenteric ischemia, on the other hand, does not initially cause any symptoms, as the intestine is supplied by several vessels and a narrowing of one vessel can usually be compensated for well. At an advanced stage, a chronic circulatory disorder of the intestine often manifests itself through abdominal pain or discomfort, especially after eating, and also through weight loss. These symptoms occur because the intestine needs more blood for digestion, but not enough blood reaches the intestine due to vasoconstriction.

Mesenteric ischemia – frequency and age

The incidence of mesenteric ischemia cannot be precisely quantified. Experts estimate that around one to two percent of all acute abdominal diseases are caused by mesenteric circulatory disorders. There are also no exact figures on chronic mesenteric ischemia. Doctors assume a frequency of two to four affected persons per 100,000 inhabitants. Women are affected about four times more often than men. Because people are getting older and older and arteriosclerosis is a symptom of old age, we expect the numbers to rise in the future. Vascular calcification affects all vessels in the body – including the intestinal vessels.

Mesenteric ischemia: causes and risk factors

The causes of mesenteric ischemia vary. There are other reasons for acute circulatory disturbance of the intestinal vessels than for chronic mesenteric ischemia.

Acute mesenteric ischemia: causes

In acute mesenteric ischemia, a blood vessel is blocked by a blood clot (thrombus) or an embolus (vascular plug) from another part of the body, resulting in an intestinal infarction:

• Arterial embolism: A blood clot breaks loose, enters an intestinal vessel with the blood flow and blocks it. The most common causes are cardiac arrhythmia (e.g. atrial fibrillation), heart attack, heart valve disease, heart valve prostheses, dilated heart muscle (dilated cardiomyopathy) or inflammation of the inner lining of the heart (endocarditis).
• Acute thrombosis in an intestinal vessel: Due to vascular calcification, a blood clot forms which acutely blocks and occludes the intestinal vessel.

The causes can be liver cirrhosis or tumor diseases.

There are also the following causes of acute mesenteric ischemia:

• Non-occlusive mesenteric ischemia (NOD ): This special form is not caused by a vascular occlusion, but the blood flow is reduced in the entire area of the mesentery. Mesenteries are suspensory structures of the intestine that contain blood vessels, lymph nodes and nerves, among other things.
• Inflammation of the aorta, for example in the case of Takayasu’s arteritis or panarteritis nodosa

Chronic mesenteric ischemia: causes

Chronic mesenteric ischemia is the result of a prolonged, insidious process. The most common cause is vascular calcification (arteriosclerosis). Due to the deposits, the vessels lose their elasticity and become increasingly constricted – until they are completely blocked. Arteriosclerosis affects all vessels in the body. Other and rarer causes include vascular inflammation, changes to the abdominal aorta or constriction by structures outside the vessels.

The main risk factors are:

• High blood pressure
• Elevated blood lipids
• Diabetes mellitus
• Obesity
• Unhealthy diet
• Smoking
• Lack of exercise

Symptoms: Mesenteric ischemia causes abdominal pain

The symptoms of mesenteric ischemia depend on whether the intestinal vessel closes acutely or whether the process is chronic and gradual. The acute form is always an emergency in which we have to act quickly. As a rule, blood circulation must be restored as quickly as possible by surgery, otherwise more and more intestinal tissue will die. The death rate is high – between 60 and 70 percent.

Acute mesenteric ischemia: symptoms

The following symptoms occur in the first stage of acute mesenteric ischemia:

• Sudden onset of very severe abdominal pain
• Unusual bowel movements (peristalsis)
• Nausea and vomiting
• Diarrhea

The tricky thing is that the pain subsides after about six hours – the second stage follows. It is also known as the “silent interval” or “lazy peace”. This is because many of those affected now believe that the problems are over, but this is by no means the case. This is because the reduction in pain is due to the fact that the intestinal muscles are relaxed and the pain receptors are switched off by the persistent reduced blood flow – the wall tissue is now dying. The stool smells bad and is bloody.

Stage three follows approximately twelve hours after the onset of symptoms:

• The abdominal pain becomes unbearable.
• Parts of the small intestine are paralyzed and nausea and vomiting follow.
• The abdomen is tense and very hard – it shows a defensive tension (acute abdomen).
• Bloody diarrhea
• Peritonitis caused by bacteria and bacterial toxins because they penetrate the intestinal wall (peritonitis)
• The intestine can break through (intestinal perforation).
• Blood poisoning (sepsis)
• Failure of many organs and death

Chronic mesenteric ischemia: symptoms

Chronic mesenteric ischemia is initially asymptomatic. Those affected do not feel any signs of the increasing narrowing of an intestinal vessel. In the course of the disease, abdominal pain and discomfort occur after eating, which then disappear. Rapid weight loss is also common. In the advanced stage, however, discomfort, diarrhea or abdominal pain are permanently present. Chronic mesenteric ischemia is not usually an emergency. However, prompt treatment is still important in order to prevent an acute occlusion. If a mesenteric artery finally closes, an intestinal infarction occurs.

Mesenteric ischemia: diagnosis at the USZ

We must make the diagnosis of “acute mesenteric ischemia” quickly. The disease can become life-threatening if treatment is not started immediately.

Chronic mesenteric ischemia” is not usually an emergency. This usually requires extensive diagnostics.

We will first ask you a few questions about your medical history (anamnesis):

• What symptoms do you have, since when and how intense are they?
• Have you improved again in the meantime or have you become continuously stronger?
• Where exactly are the complaints localized?
• Do you have any known heart disease?
• Do you suffer from high blood pressure, high cholesterol levels or diabetes mellitus?
• Do you smoke?
• Are you taking any medications? If yes: Which ones?

Their answers provide us with the first clues to the diagnosis. This is followed by a physical examination, during which we palpate the abdomen. We test the sensitivity to pressure and pain. We also feel whether the abdomen is soft or tense and hardened (defensive tension). Listening to the abdomen shows the bowel sounds and whether the bowel is still moving.

A blood test provides further evidence of mesenteric ischemia. For example, the white blood cells (leukocytes) and lactate levels are elevated in the case of advanced reduced blood flow. The inflammation parameters C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR) show whether inflammation is taking place in the body – but not where.

We then use imaging techniques to track down the mesenteric ischemia. Examples are:

• Ultrasound of the abdomen (abdominal sonography): This method uses ultrasound waves.
• Computed tomography (CT): This method uses X-rays and a contrast medium to provide high-resolution cross-sectional images of the blood vessels and organs.
• Color duplex sonography: An ultrasound examination that can visualize not only the vessels, but also the blood flow and its flow velocity in color.
• Angiography: This X-ray method allows the mesenteric vessels to be visualized. Pictures show constrictions and occlusions. Angiography is not only suitable for diagnostics, but also for therapy. We try to open the vascular occlusion and restore blood circulation.
• Magnetic resonance imaging (MRI = magnetic resonance imaging): Radiologists use magnetic fields and obtain detailed cross-sectional images of the abdominal cavity.
• Gastroscopy/colonoscopy: gastroscopy or colonoscopy to assess the stomach and intestinal mucosa in the chronic form

Acute mesenteric ischemia often requires immediate emergency intervention or surgery, for example in the case of peritonitis or if a life-threatening cardiovascular shock is imminent. CT is the first choice for diagnosis and must be performed as quickly as possible. All other imaging examinations are of secondary importance.

Mesenteric ischemia: prevention, early detection, prognosis

You can prevent mesenteric ischemia to a certain extent with the following measures:

• Get adequate treatment for heart disease, for example cardiac arrhythmia, valvular heart disease or enlargement of the heart muscle.
• A healthy lifestyle can offer some protection against a heart attack: A healthy diet, not smoking, plenty of exercise, moderate alcohol consumption and little stress. A healthy lifestyle not only protects the blood vessels and prevents vascular calcification, but also keeps other organs healthy.
• Have existing illnesses such as high blood pressure, high cholesterol levels or diabetes mellitus adequately treated. These promote arteriosclerosis and thus also mesenteric ischemia.
• You should have an aortic aneurysm and inflammation of the aorta regularly monitored and checked by a doctor.

There are no specific measures for the early detection of mesenteric ischemia. Have regular check-ups and check-ups with your doctor. This is especially true if you already suffer from an underlying disease. And if you experience symptoms such as sudden, severe abdominal pain, call an emergency doctor. Do not wait long to see if the symptoms improve again – this can be life-threatening in the case of mesenteric ischemia.

Course and prognosis of mesenteric ischemia

The course and prognosis of acute mesenteric ischemia are unfavorable in many cases. The mortality rate is between 60 and 70 percent. It has remained high for years. Rapid treatment is crucial for the chances of survival in order to keep the reduced blood flow as short as possible. The faster the therapy is started, the lower the risk of intestinal damage and the better the prognosis.

The location where the vascular occlusion occurred also plays a role in the course and prognosis. Peripheral occlusions have a better prognosis than a central occlusion because the body can still maintain a certain blood supply to the intestine via side branches.

Mesenteric ischemia: treatment restores blood flow

Treatment of acute mesenteric ischemia must begin quickly, otherwise intestinal tissue will no longer be supplied with blood and will die. There is also a risk of life-threatening consequences such as a ruptured intestine with peritonitis or blood poisoning (sepsis).

If there are indications of peritonitis or a proven occlusion of the superior mesenteric artery, an emergency operation is performed immediately – an open operation with an abdominal incision (laparotomy).

The treatment of chronic mesenteric ischemia should be planned. Priority is given to catheter procedures to improve blood flow and vascular patency. If a catheter procedure is not possible due to severe calcification or a long-distance occlusion of the vessel, surgery is often required to peel out the vessel or create a bypass. We will be happy to advise you on both procedures during our vascular surgery consultation hours.