AV fistula pseudoaneurysmCase: A 45 year old female with end-stage renal disease presents with 2 days of worsening pain, swelling, and color change of her left upper extremity.  The symptoms began after her left arm arteriovenous (AV) fistula was accessed for hemodialysis. The skin is tense and a bruit is present. What is your diagnosis for this swollen upper extremity? Click on the image for a larger view.

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AV fistula pseudoaneurysm


After thrombosis and infection, false or “pseudo” aneurysms are the third most frequent complication of hemoaccess.  They occur in 2-10% of patients and are thought to be caused by repeated needle punctures in the same location.1

While true aneurysms include layers of the arterial wall, pseudoaneurysms are caused by defects in vessel walls that result in hematomas contained by tissues outside the arterial wall – hence the term “pseudo”.  They present with a painful swollen upper extremity with tense overlying skin.

Diagnosis can be made by bedside ultrasound demonstrating the classic “yin and yang sign” of swirling blood within the aneurysm.2 Of note, the yin-yang sign can be seen for true aneurysms and pseudoaneurysms. Definitive correction of a pseudoaneurysm can be performed by ultrasound compression, endovascular repair, or surgical repair.

YinYang Ultrasound

Yin and Yang Sign [image credit]

Rodriguez H, Leon L, Schalch P, Labropoulos N, Borge M, Kalman P. Arteriovenous access: managing common problems. Perspect Vasc Surg Endovasc Ther. 2005;17(2):155-166. [PubMed]
Arshad F, Sutijono D, Moore C. Emergency ultrasound diagnosis of a pseudoaneurysm associated with an arteriovenous fistula. Acad Emerg Med. 2010;17(6):e43-5. [PubMed]
Jeff Riddell, MD

Jeff Riddell, MD

Assistant Professor of Clinical Emergency Medicine
Co-Director, Medical Education Fellowship
LA County + USC Emergency Medicine Residency, Department of Emergency Medicine
Keck School of Medicine of the University of Southern California