University of Wisconsin–Madison Medical College of Wisconsin

Segmental Arterial Mediolysis: An Unusual Case Mistaken to be a Strangulated Hernia

Russell D. Japikse, MD, PhD; James E. Svenson, MD, MS; Perry J. Pickhardt, MD; Michael D. Repplinger, MD, PhD

WMJ. 2019;118(1):173-176

Download full text pdf.


Introduction: Segmental arterial mediolysis (SAM) is a rare nonatherosclerotic, noninflammatory vasculopathy causing arterial wall necrosis that leads to strictures, dissections, and aneurysms, particularly in medium-sized abdominal arteries. Awareness of SAM is important because, unlike vasculitides, immunosuppressive treatment may worsen the disease process.

Case: A 58-year-old man with multiple medical comorbidities presented with acute epigastric pain and a right incarcerated inguinal hernia that was interpreted as showing bowel strangulation on computed tomography. The hernia was unable to be educed in the emergency department, so the patient was taken for open reduction by the surgical service. Intraoperatively, he was noted to have a ruptured superior mesenteric artery aneurysm. Conventional angiography demonstrated a bead-like appearance of several jejunal branches of the superior mesenteric artery, raising concern for a vasculitis. His hospital course included rheumatologic consultation, and initial recommendations were to start immunosuppressive therapy for treatment of polyarteritis nodosa. Further testing demonstrated normal antinuclear antibody, antineutrophil cytoplasmic antibodies, and complement levels. Due to a lack of systemic symptoms or signs and otherwise unremarkable laboratory evaluation, the patient ultimately was diagnosed with SAM and immunosuppressive therapy was halted.

Discussion: Unexplained medium arterial stenosis, dissection, aneurysm, and hemorrhage should raise suspicion for possible SAM. The initial management approach should focus on treatment of the acute hemorrhage, usually involving endovascular stenting or coil embolization. Unlike vasculitides, SAM does not benefit from, and may actually be harmed by, immunosuppressive therapy.

Conclusions: Clinicians involved in the longitudinal care of emergency department patients should be aware of this rare clinical entity in order to initiate appropriate treatment.

Author Affiliations: University of Wisconsin, BerbeeWalsh Department of Emergency Medicine, Madison, Wis (Japikse, Svenson, Repplinger); University of Wisconsin, Department of Radiology, Madison, Wis (Pickhardt, Repplinger).
Corresponding Author: Michael D. Repplinger, MD, PhD, BerbeeWalsh Department of Emergency Medicine, University of Wisconsin, 800 University Bay Dr, Suite 310 Mail Code 9123, Madison, WI 53705; phone 608.890.5963; fax 608.265.8241; e-mail
Funding/Support: The project described was supported by the Clinical and Translational Science Award (CTSA) program, through the NIH National Center for Advancing Translational Sciences (NCATS), grant UL1TR000427 and KL2TR000428.
Financial Disclosures: Dr Pickhardt is cofounder of VirtuoCTC, a company involved in CTC colonography education and training. He is also a shareholder in SHINE and Cellectar Biosciences, companies involved in radionuclide production and early-stage cancer treatment, respectively.
Share WMJ