Acute Mesenteric Ischemia

64-year-old male with sudden onset abdominal pain and lactic acidosis. Diagnosis? • Xray of the Week

Figure 1. What are the important findings?

Figure 2.

A: Axial CT. Gas in the wall of the transverse colon (orange arrow).

B: Axial CT- lung window. Gas in the wall of the transverse colon- pneumatosis intestinalis (orange arrow).

C: Coronal CT. Gas in the wall of the transverse colon (orange arrow). Gas in the mesenteric portal venous system (red arrow). Gas in the intrahepatic portal venous system (green arrow).

D: Coronal CT- lung window. Gas in the wall of the transverse colon- pneumatosis intestinalis. (orange arrow).

E: Axial CT. Gas in the intrahepatic portal venous system (green arrow).

F: Axial CT- lung window. Gas in the mesenteric portal venous system (red arrow).

Discussion:

Bowel ischemia is an often fatal condition caused by reduction in blood supply to the bowel and its mesentery. Three possible causes include severe hypotension, atherosclerosis, and thromboembolism which usually manifest as ischemic colitis, chronic mesenteric ischemia (CMI), and acute mesenteric ischemia (AMI), respectively [1]. AMI carries a high mortality rate of approximately 70% with an estimated incidence of 1 to 2 per 1000 hospital admissions [2,3]. Most AMI patients present with sudden onset of abdominal pain that is disproportionate to physical findings, especially with a history of cardiovascular disease. Unfortunately, no laboratory test is sufficiently sensitive or specific to rule in or rule out early bowel ischemia thus imaging and compatible history and physical examination are the cornerstone of early diagnosis [4].

CT angiography is the current standard for diagnosis of AMI with a sensitivity of 96% and specificity of 94%, especially with findings of pneumatosis intestinalis (Fig. 2 orange arrows) and hepatic portal venous gas (Fig. 2 green arrows) as seen in this patient [5]. Furthermore, data suggests combination of pneumatosis intestinalis and hepatic portal venous gas is associated with the presence of bowel ischemia in approximately 70% of all cases indicating advanced stage disease [2,6]. The quantity of hepatic portal venous gas is associated with bowel necrosis, whereas the presence of free air or air-type pneumatosis intestinalis (pneumatosis intestinalis of the entire circumference of the intestine without wall edema) is associated with non-necrosis of the bowel [7]. However, for non-occlusive mesenteric ischemia (NOMI), digital subtraction angiogram is the standard for both diagnosis and treatment.

Treatment of mesenteric ischemia is multimodal depending on the etiology. Non surgical treatment may include drug therapy with thrombolysis, heparin, or vasodilators. Interventional radiology rarely may play a role with angioplasty and stenting [8]. However, surgery remains the treatment of choice for patients with acute abdominal pain, peritoneal signs, and suspected AMI as seen in this case [3,9]. Despite treatment mortality remains high ranging between 30 and 90% [9].

References:

1. Dhatt HS, Behr SC, Miracle A, Wang ZJ, Yeh BM. Radiological Evaluation of Bowel Ischemia. Radiol Clin North Am. 2015;53(6):1241-1254. Accessed May 15, 2021. doi:10.1016/j.rcl.2015.06.009.

2. Milone M, Di Minno, Matteo Nicola Dario, Musella M, et al. Computed tomography findings of pneumatosis and portomesenteric venous gas in acute bowel ischemia. World J Gastroenterol. 2013;19(39):6579-6584. Accessed May 15, 2021. doi:10.3748/wjg.v19.i39.6579.

3. Endean ED, Barnes SL, Kwolek CJ, Minion DJ, Schwarcz TH, Mentzer RM. Surgical management of thrombotic acute intestinal ischemia. Ann Surg. 2001;233(6):801-808. Accessed May 15, 2021. doi:10.1097/00000658-200106000-00010.

4. Oldenburg WA, Lau LL, Rodenberg TJ, Edmonds HJ, Burger CD. Acute mesenteric ischemia: a clinical review. Arch Intern Med. 2004;164(10):1054-1062. Accessed May 15, 2021. doi:10.1001/archinte.164.10.1054.

5. van den Heijkant, Teun C., Aerts BAC, Teijink JA, Buurman WA, Luyer MDP. Challenges in diagnosing mesenteric ischemia. World J Gastroenterol. 2013;19(9):1338-1341. Accessed May 15, 2021. doi:10.3748/wjg.v19.i9.1338.

6. Angelelli G, Scardapane A, Memeo M, Stabile Ianora AA, Rotondo A. Acute bowel ischemia: CT findings. Eur J Radiol. 2004;50(1):37-47. Accessed May 15, 2021. doi:10.1016/j.ejrad.2003.11.013.

7. Muratsu A, Muroya T, Yui R, et al. Factors associated with bowel necrosis in patients with hepatic portal venous gas and pneumatosis intestinalis. Acute Med Surg. 2020;7(1):e432. Accessed May 15, 2021. doi:10.1002/ams2.432.

8. Goldberg MF, Kim HS. Treatment of acute superior mesenteric vein thrombosis with percutaneous techniques. AJR Am J Roentgenol. 2003;181(5):1305-1307. doi:10.2214/ajr.181.5.1811305

9. Fitzpatrick LA, Rivers-Bowerman MD, Thipphavong S, Clarke SE, Rowe JA, Costa AF. Pearls, Pitfalls, and Conditions that Mimic Mesenteric Ischemia at CT. Radiographics. 2020;40(2):545-561. doi:10.1148/rg.2020190122

Savan V. Patel is a medical student and aspiring diagnostic radiologist at Rowan University School of Osteopathic Medicine in New Jersey. During his time as a medical student, Savan served as the vice president of Inclusion, Diversity, Equity, and Action (IDEA) council. Prior to medical school, he earned MS in Pharmaceutical Sciences with summa cum laude at Rowan University where he published research on novel compounds composed of cyanopyrrolidines and β-amino alcohol scaffolds tested in vitro against Dipeptidyl Peptidase IV (DPP-IV) enzyme, a key regulator of incretin hormones in the management of type 2 diabetes. He graduated magna cum laude from Rowan University where he completed his studies in biochemistry with a minor in biology. Outside of medical school, Savan loves to travel with his wife, cook new cuisines and listen to Bollywood music.

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Kevin M. Rice, MD is the president of Global Radiology CME

Dr. Rice is a radiologist with Renaissance Imaging Medical Associates and is currently the Vice Chief of Staff at Valley Presbyterian Hospital in Los Angeles, California. Dr. Rice has made several media appearances as part of his ongoing commitment to public education. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015, Dr. Rice and Natalie Rice founded Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field. In 2016, Dr. Rice was nominated and became a semifinalist for a "Minnie" Award for the Most Effective Radiology Educator.

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