Mesenteric ischemia (mez-un-TER-ik is-KEE-me-uh) occurs when narrowed or blocked arteries restrict blood flow to your small intestine. Decreased blood flow can permanently damage the small intestine.

Sudden loss of blood flow to the small intestine (acute mesenteric ischemia) from a blood clot requires immediate surgery. Mesenteric ischemia that develops over time (chronic) is treated with angioplasty or open surgery.

Untreated, chronic mesenteric ischemia can become acute or lead to severe weight loss and malnutrition.

Acute mesenteric ischemia

Signs and symptoms of the acute form of mesenteric ischemia include:

• Abrupt, severe abdominal pain
• Urgent need to have a bowel movement
• Fever
• Nausea and vomiting

Chronic mesenteric ischemia

Signs and symptoms of the chronic form of mesenteric ischemia include:

• Abdominal pain that starts about 30 minutes after eating
• Pain that worsens over an hour
• Pain that goes away within one to three hours

When to see a doctor

If you have severe, abrupt abdominal pain that persists, seek emergency medical care. If you develop pain after eating, make an appointment with your doctor.

Both acute and chronic mesenteric ischemia are caused by a decrease in blood flow to the small intestine. Acute mesenteric ischemia is most commonly caused by a blood clot in the main mesenteric artery. The blood clot often originates in the heart. The chronic form is most commonly caused by a buildup of plaque that narrows the arteries.

If not treated promptly, acute mesenteric ischemia can lead to:

• Sepsis. This potentially life-threatening condition is caused by the body releasing chemicals into the bloodstream to fight infection. In sepsis, the body overreacts to the chemicals, triggering changes that can lead to multiple organ failure.
• Irreversible bowel damage. Insufficient blood flow to the bowel can cause parts of the bowel to die.
• Death. Both of the above complications can lead to death.

People with chronic mesenteric ischemia can develop:

• Fear of eating. This occurs because of the after-meal pain associated with the condition.
• Unintentional weight loss. This can occur as a result of the fear of eating.
• Acute-on-chronic mesenteric ischemia. Symptoms of chronic mesenteric ischemia can progress, leading to the acute form of the condition.

Your doctor might suspect that you have chronic mesenteric ischemia if you have pain after eating that causes you to limit food and lose weight. A narrowing of the major arteries to the small intestine can help confirm the diagnosis.

Tests might include:

• Angiography. Your doctor might recommend a CT scan, MRI or X-ray of your abdomen to determine if the arteries to your small intestine have narrowed. Adding a contrast dye (mesenteric angiogram, CT angiography or magnetic resonance angiography) can help pinpoint the narrowing.
• Doppler ultrasound. This noninvasive test uses sound waves to estimate blood flow, which can determine narrowing of the arteries.

If a blood clot causes a sudden loss of blood flow to the small intestine, you might require immediate surgery to treat your mesenteric ischemia. Mesenteric ischemia that develops over time might be treated with a procedure that uses a balloon to open the narrowed area.

A mesh tube (stent) might be placed in the narrowed area. Mesenteric ischemia can also be treated via open surgery through an incision.