Overview
Definition
A sudden decrease in blood flow to the bowel, resulting in severe ischemia and potentially necrosis.
Epidemiology
More common in older adults with cardiovascular disease. High mortality rate (up to 70%).
Etiology & Risk Factors
- Superior Mesenteric Artery (SMA) Embolism (most common, often from Atrial Fibrillation)
- SMA Thrombosis (at a site of severe atherosclerosis)
- Non-occlusive mesenteric ischemia (NOMI) due to severe hypotension/shock
- Mesenteric venous thrombosis (MVT)
Clinical Symptoms
- 'Pain out of proportion to physical exam' (Severe, unrelenting abdominal pain but a relatively soft, non-tender abdomen early on)
- Nausea, vomiting, diarrhea (often bloody)
Clinical Approach
Diagnosis
- CT Angiography (CTA) of the Abdomen (Gold Standard): Shows occlusion of mesenteric vessels or bowel wall thickening/pneumatosis
- Labs: Lactic acidosis (a late, ominous sign of bowel necrosis), leukocytosis
Management
- Resuscitation: Aggressive IV fluids, correct electrolytes, start broad-spectrum antibiotics
- Embolic/Thrombotic: Emergent surgical revascularization (embolectomy) or endovascular therapy, PLUS resection of any clearly necrotic bowel
- Non-occlusive: Treat the underlying shock and improve perfusion
Complications
- Extensive bowel necrosis (requiring massive resection leading to Short Bowel Syndrome)
- Septic shock and death