Portal Vein Gas From Mesenteric Ischemia
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A 78-year-old man with diabetes, hypertension, and end-stage renal disease presented to the emergency department (ED) with diffuse abdominal pain that started while he was receiving hemodialysis. He described the pain as crampy and more severe in the lower abdomen. He also felt nauseated and vomited non-bilious, non-bloody stomach contents several times. Because of the pain, he was able to complete only 2 hours of dialysis.
On arrival at the ED, the patient was awake but confused and his abdomen was firm, distended, and tympanitic, with rebound and guarding. No bowel sounds were audible. Vital signs and the rest of the physical examination findings were normal.
The patient’s lactate level was 6 mmol/L. White blood cell count was 15,500/µL. A CT scan of the abdomen and pelvis showed diffuse bowel wall thickening, pneumatosis intestinalis (A), pneumobilia, and pneumatosis of the portal system (B and C).
Small bowel ischemia was diagnosed. After extensive discussion with the patient and his family, a decision was made for no further surgical intervention given the patient’s poor general condition. He was enrolled in hospice care and died within 24 hours.
Acute insufficiency of mesenteric arterial blood flow accounts for 60% to 70% of cases of mesenteric ischemia and results in mortality rates exceeding 60%.1 Specific risk factors include advanced age, atherosclerosis, low cardiac output states, cardiac arrhythmias, severe cardiac valvular disease, recent myocardial infarction, and intra-abdominal malignancy.1
The diagnosis of acute mesenteric ischemia depends on a high clinical suspicion, especially in patients with known risk factors (such as atrial fibrillation, congestive heart failure, peripheral vascular disease, or a history of hypercoagulability). Rapid diagnosis is essential to prevent the catastrophic events associated with intestinal infarction.
Mesenteric angiography remains the “gold-standard” diagnostic study for acute arterial ischemia. CT of the abdomen may show focal or segmental bowel wall thickening or intestinal pneumatosis with portal vein gas. Magnetic resonance angiography and the newest generation of CT angiography, known as multidetector row CT, can provide much more detailed information about the mesenteric vessels and the small bowel than their predecessors.2-4 Therapeutic options during angiography include intra-arterial vasodilators or thrombolytic agents or angioplasty or placement of vascular stents and embolectomy depending on the cause of ischemia. Intra-arterial papaverine is useful in occlusive and non-occlusive mesenteric ischemia and can be used for 5 days.5,6
1. McKinsey JF, Gewertz BL. Acute mesenteric ischemia. Surg Clin North Am. 1997;77(2):307-318.
2. Mitsuyoshi A, Obama K, Shinkura N, Ito T, Zaima M. Survival in nonocclusive mesenteric ischemia: early diagnosis by multidetector row computed tomography and early treatment with continuous intravenous high-dose prostaglandin E(1). Ann Surg. 2007;246(2):229-235.
3. Kim AY, Ha HK. Evaluation of suspected mesenteric ischemia: efficacy of radiologic studies. Radiol Clin North Am. 2003;41(2):327-342.
4. Horton KM, Fishman EK. The current status of multidetector row CT and three-dimensional imaging of the small bowel. Radiol Clin North Am. 2003;41(2):199-212.
5. Boley SJ, Brandt LJ, Sammartano RJ. History of mesenteric ischemia. The evolution of a diagnosis and management. Surg Clin North Am. 1997; 77(2):275-288.
6. Bassiouny HS. Nonocclusive mesenteric ischemia. Surg Clin North Am. 1997;77(2):319-326.