A 22-year-old woman presented to the ED with severe left arm pain and hand weakness eight days after an open reduction and internal fixation for a left proximal humerus fracture. Her pain was severe, burning, worse with arm movement, and not relieved by oral opioids. She had been seen in the clinic three days after the surgery, and was noted to have a new radial nerve palsy, which included numbness over her left thumb. Now she reported progressive pain, new numbness in her left little finger, and finger weakness.
She was tachycardic to 110 bpm, but her vital signs were otherwise within normal limits and she was crying in pain. Her surgical incisions were healing well. She had swelling, ecchymosis, and tenderness over the anterior shoulder and axilla. Brachial, radial, and ulnar pulses were 2+. She had decreased sensation to light touch over the radial aspect of her thumb, the ulnar half of her ring finger, and her entire little finger. She also had weakness of elbow extension, wrist extension, and finger abduction and adduction. She was unable to cross her ring and middle fingers. A soft bruit could be auscultated in her left axilla.
What imaging studies should be obtained? What is the diagnosis and treatment?
Find the diagnosis and case discussion on the next page.
Diagnosis: Traumatic Pseudoaneurysm with Brachial Plexus Compression
A CT angiogram of the left shoulder revealed a 5.1 cm pseudoaneurysm arising from the left distal axillary artery with compression of the brachial plexus and surrounding hematoma.
Traumatic pseudoaneurysm is an injury-related arterial dilation caused by disruption of the layers of the arterial wall with subsequent collection of blood between the tunica adventitia and tunica media. There can be persistent flow from the arterial lumen into the surrounding tissue, and symptoms arise as the pseudoaneurysm or associated hematoma expands. (Curr Treat Options Cardiovasc Med. 2008;10:173.) Vascular injury in the axillary region often results from high-energy shoulder trauma, such as penetrating trauma, shoulder dislocation, or fractures. (Vasc Endovascular Surg. 2018;52:371.)
The onset of clinical signs can occur days to months after the initial trauma. When nerve compression is present, symptoms include paresthesia, weakness, and severe pain often refractory to standard analgesics. A pulsatile soft tissue mass can sometimes be palpated in the axillary fossa or infraclavicular region. There may be overlying skin changes, as well as upper-extremity edema, pallor, or reduced temperature. (Curr Treat Options Cardiovasc Med. 2008;10:173.)
Pulses may be decreased, but there is adequate collateral blood supply to the arm, which can obscure detection of vascular injury. (J Cardiovasc Surg [Torino]. 1998;39:167.) The adjacent brachial plexus is especially susceptible to compression, and the resulting neurological deficits in one or more nerve distributions may be the only presenting sign. Other complications include compression of adjacent veins with resulting edema, thromboembolic events, limb ischemia, and hemorrhage.
Arterial imaging with Doppler ultrasonography or CT angiography is indicated for diagnosis. Duplex scanning is noninvasive and easy to perform, while CT imaging is used preoperatively to determine the site and extent of vascular injury and to guide surgical management. (Vasc Endovascular Surg. 2008;42:65.) It is recommended that imaging be obtained following all penetrating trauma to the axilla despite a normal neurovascular examination and after trauma with vascular deficits or with brachial plexus palsy on initial or follow-up exam. (J Trauma. 1984;24:350.) Evidence of hemodynamic instability, distal limb ischemia, overlying skin changes, expanding hematoma, or active bleeding should prompt emergent consultation with vascular surgery.
Treatment commonly requires multidisciplinary management with orthopedics, vascular surgery, and neurosurgery. Initial noninvasive management, including ultrasound-guided compression and percutaneous thrombin injection, has been described for asymptomatic patients with small pseudoaneurysms. (Curr Treat Options Cardiovasc Med. 2008;10:173.) Open surgical exploration may be preferred for symptomatic patients, especially those with neurologic deficits from compression of the adjacent brachial plexus, because it allows for hematoma evacuation and decompression of the surrounding structures. Endovascular treatment (e.g., stenting or coiling) is an option for patients who are otherwise poor surgical candidates. The literature on this topic is limited to case series, and no consensus exists on concrete indications for the choice of treatment.
Surgery has a high success rate for correcting vascular deficits and reducing pain secondary to pseudoaneurysm formation, but neurologic functional recovery remains limited, particularly if decompression is delayed from onset of symptoms, making timely diagnosis and treatment important. (Vasc Endovascular Surg. 2008;42:65.)
This patient was admitted, and had a bridging stent placed by interventional radiology. This was complicated by stent thrombosis, after which the patient underwent emergent axillary bypass grafting and hematoma evacuation by vascular surgery. At a follow-up visit, her pain was improving, but strength and sensation had not meaningfully returned.
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Dr. Vartanyanis a third-year emergency medicine resident at LAC+USC Medical Center. Dr. Burkholderis an assistant professor of clinical emergency medicine at the Keck School of Medicine at the University of Southern California. Follow him on Twitter@tayburkholder.