Mesenteric artery occlusion is one of the rarer cerebrovascular emergencies in the abdomen, but it occurs more frequently in older people. Epidemiologically, it is known that patients with atrial fibrillation, cardiac arrhythmias or severe atherosclerosis are at particularly high risk. Acute mesenteric infarction is usually caused by an embolus that is dislodged from the heart and blocks a mesenteric artery. Arterial thrombosis also plays a role, particularly in pre-existing vascular damage where the vessels are already narrowed. Recurrent abdominal pain after eating – known as abdominal angina – may be an indication of upstream mesenteric artery stenosis.
The etiology shows that the occlusion of a vessel never occurs by chance, but is almost always attributable to clearly identifiable risk factors. These include arterial circulatory disorders, chronic vascular diseases and coagulation disorders such as an imbalance in anticoagulation. Acute mesenteric artery occlusion can also result from thrombosis when local blood clotting is strongly activated. In rare cases, the occlusion is precipitated by trauma, abdominal surgery or inflammatory processes. The etiology is therefore complex and requires thorough investigation.
In clinical practice, mesenteric artery occlusion is often recognized late, as patients initially present with only non-specific symptoms. These non-specific symptoms make early diagnosis difficult and contribute to the severe clinical course. The epidemiology also shows that many cases are only diagnosed at an advanced stage. The combination of embolism, thrombosis and atherosclerotic processes forms the basis of most cases. Without rapid intervention, there is a risk of severe ischemia in sections of the intestine.
A blood clot blocks the mesenteric artery and interrupts the vital blood supply to the intestine.
What are the symptoms of mesenteric artery occlusion?
Symptoms often begin suddenly with severe abdominal pain, which initially appears disproportionately severe compared to the visible findings. This discrepancy is typical of mesenteric artery occlusion, as blood flow to the bowel is abruptly cut off. This is accompanied by nausea, vomiting and increasing abdominal rigidity, indicating a developing acute abdomen. Some patients describe the pain as wave-like, which can lead to misinterpretation at the outset. Early recognition of these symptoms can be life-saving.
As the condition progresses, the clinical picture deteriorates dramatically. Due to persistent ischemia, the affected intestinal peristalsis ceases to function, which can lead to intestinal paralysis and gas-filled sections of the bowel. Progressive necrosis of the intestinal wall is a feared complication. In the event of complete obstruction, toxins can enter the bloodstream and trigger sepsis or blood poisoning. The rapid deterioration in vital signs requires immediate emergency measures.
Cases detected too late often present with acute mesenteric infarction, characterized by severe abdominal distension and circulatory instability. The abdomen becomes increasingly hard, tender and barely reacts to pressure. The combination of pain, vomiting and circulatory disturbance is typical of the advanced clinical picture. As symptoms may begin non-specifically, a high degree of vigilance is required. Early hospital admission can prevent secondary damage.
Diagnosis and treatment of mesenteric artery occlusion
Diagnosis begins with a rapid clinical assessment, as mesenteric artery occlusion is an absolute medical emergency. The doctor assesses abdominal pain, guarding and the clinical presentation of a possible acute abdomen. Blood tests often show elevated lactate levels due to ischemia. However, a physical examination alone is not sufficient, as the non-specific symptoms can be misleading at first. Imaging diagnostics are therefore initiated at an early stage.
CT angiography is the most important procedure for detecting occlusion of a mesenteric artery. It shows whether a blood clot or an embolus is blocking the mesenteric artery and which sections of the bowel are affected. Stenoses or near-complete occlusion also become visible. Angiography also allows the stage of ischemia to be assessed. In diagnostically challenging cases, conventional angiography may also be used.
Other procedures aid in making the diagnosis. The duplex ultrasound procedure can provide experienced practitioners with indications of circulatory disturbances. In rare cases, diagnostic laparoscopy is advisable if the findings are unclear and an acute mesenteric infarction cannot be ruled out. The diagnosis must be made quickly, as every moment lost reduces the chance of survival. The earlier the occlusion is detected, the better the prognosis.
Depending on the stage, treatment consists of a combination of medical and surgical measures. Initially, heparin is often administered for anticoagulation to halt the progression of thrombosis. In cases of embolic occlusion, removal of the blood clot is crucial. In the early stages, endovascular treatment, such as the interventional removal or dissolution of the clot, is an effective option. These procedures are primarily carried out in specialist centers.
If the bowel is already damaged, immediate surgical treatment is required. The affected section of the bowel is operated on to remove necrotic tissue and prevent the life-threatening consequences of ischemia. Depending on the findings, reconstruction of the affected artery may also be performed, for example by creating a bypass. In extreme cases, a large area of bowel tissue must be resected to prevent sepsis. Vascular surgical management is often complex and requires a specialized team.
In some cases, treatment may also be endovascular, particularly if the diagnosis is made early. In this procedure, the mesenteric artery is examined using angiography and the occlusion is removed, for example, by means of a stent. The choice between surgical and interventional approaches depends on the clinical presentation, the timing of the diagnosis and the extent of necrosis. Consistent follow-up care is crucial to prevent recurrent occlusions. This also includes the long-term management of potential risk factors.
The prognosis depends largely on how quickly the mesenteric artery occlusion is detected and treated. With a very early diagnosis, treatment and intervention can restore blood flow before the bowel is irreversibly damaged. However, delays lead to necrosis, sepsis and a greatly increased risk of death. The clinical picture deteriorates extremely rapidly, which is why every hour counts. Early intervention can drastically improve the chances of survival.
The course of an acute mesenteric infarction is often severe if the occlusion is not detected until late. Many patients do not arrive at hospital until several hours have passed, which complicates treatment. In cases of advanced ischemia, the bowel is often beyond saving, and large sections must be resected. Despite surgery, the risk of complications remains high. Close intensive care is then necessary.
In the long term, the prognosis depends on the cause. Embolic occlusions have a better chance of recovery than those caused by atherosclerosis, as the artery is often unblocked again after the blood clot has been removed. Consistent management of risk factors such as arterial hypertension, atrial fibrillation or vascular disease is essential. Recurrent abdominal pain should always be investigated, as it may be a sign of mesenteric artery stenosis. Early preventive treatment can help prevent further occlusions.
How does mesenteric artery occlusion present in the early stages?
Initially, the symptoms often appear non-specific and resemble abdominal angina, which delays diagnosis. Patients may experience diffuse abdominal pain, even though blood flow to the intestine is already reduced. These non-specific symptoms mean that the acute condition is often not recognized until late. It is often only the clinical picture that reveals the severity of the occlusion.
Why is an acute mesenteric infarction considered a medical emergency?
Because the complete occlusion of a mesenteric artery abruptly interrupts the blood supply to the intestine. Within a short time, there is a risk of ischemia, necrosis and life-threatening sepsis. The occlusion of a vessel of this size rapidly leads to serious complications. Only immediate treatment can prevent irreversible damage.
What role do thrombosis and embolism play in the development of the occlusion?
An acute mesenteric artery occlusion is often caused by a blood clot, usually as part of an embolism associated with atrial fibrillation or cardiac arrhythmias. Arterial thrombosis due to atherosclerosis or mesenteric artery stenosis may also be involved. The vessels are sensitive to such occlusions. The risk increases with age and the presence of existing vascular diseases.
Which investigations help to reliably identify the occlusion?
A CT angiogram provides important information, as it shows the course of the occlusion, the affected sections of the intestine and the extent of the ischemia. Detecting an occluded vessel is crucial for determining further treatment in this condition. In some cases, conventional angiography is also performed. This allows for an interventional procedure to be carried out at the same time, if necessary.
