Acute mesenteric ischemia (AMI) is a life-threatening surgical emergency characterized by the abrupt onset of blood flow restriction (hypoperfusion) to a portion of the small intestine. This disruption may be either occlusive or non-occlusive, affecting primarily the superior mesenteric artery.

Epidemiology

Acute mesenteric ischemia is a relatively rare but serious condition, representing approximately 0.1% of all hospital admissions. However, it's associated with high morbidity and mortality rates, with the mortality rate ranging from 60-80%. Age is a significant factor, with the majority of cases occurring in individuals over 60 years old.

Aetiology

The causes of AMI can broadly be categorized as follows:

• Arterial Embolism: The most common cause, often resulting from atrial fibrillation or other embolic sources such as infective endocarditis or aortic aneurysm.
• Arterial Thrombosis: Usually associated with atherosclerosis, especially in patients with a history of ischemic heart disease or peripheral vascular disease.
• Venous Thrombosis: Occurs less commonly and is often linked to hypercoagulable states.
• Non-Occlusive Mesenteric Ischemia: Typically associated with low-flow states such as heart failure, shock, or during major surgery.

PC

Triad of severe abdominal pain, normal abdominal examination and shock

• Sudden severe abdominal pain and guarding, often out of proportion to the physical examination
• Nausea and vomiting
• Rectal bleeding can occasionally be seen in advanced ischemia
• Signs of shock, such as hypotension, tachycardia, altered mental status

Differentials: