Thoracic Outlet Syndrome in Emergency Medicine Workup

Updated: Aug 25, 2020
  • Author: Andrew K Chang, MD, MS; Chief Editor: Erik D Schraga, MD  more...
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Approach Considerations

With the rare exception of a vascular cause, the vast majority of emergency department presentations of thoracic outlet syndrome are not emergent. Screening tests may be appropriate if indicated and to rule out other causes. Once the clinical diagnosis is made, most of the imaging studies and other tests should be reserved for the outpatient setting.


Imaging Studies

The noninvasive imaging modality of choice in evaluating patients with suspected thoracic outlet syndrome (TOS) is magnetic resonance imaging (MRI). However, computed tomography (CT) scanning plays an important role as well, especially in delineating bone anatomy. [7]


Cervical radiography may demonstrate a skeletal abnormality [8]

Chest radiography findings may include the following:

  • Cervical or first rib: This is usually associated with the arterial form of TOS but also can be a predisposition to developing the neurologic form following neck trauma.

  • Clavicle deformity

  • Pulmonary disease

  • Pancoast tumor


Color flow duplex scanning for suspected arterial or vascular TOS may be indicated. [9]


Indications for arteriography include the following:

  • Evidence of peripheral emboli in the upper extremity

  • Suspected subclavian stenosis or aneurysm (eg, bruit or abnormal supraclavicular pulsation)

  • Blood pressure differential greater than 20 mm Hg

  • Obliteration of radial pulse during elevated arm stress test (EAST)


Indications for venography include the following:

  • Persistent or intermittent edema of the hand or arm

  • Peripheral unilateral cyanosis

  • Prominent venous pattern over the arm, shoulder, or chest


Other Tests

The following special studies are generally appropriate in the outpatient setting; they should be arranged by the primary care physician once the patient has been discharged from the emergency department:

  • Nerve conduction evaluation via root stimulation and F wave is the best direct approach to evaluation of neurologic thoracic outlet syndrome (TOS).

  • Cervical myelogram, computed tomography (CT) scanning, or magnetic resonance imaging (MRI) may be appropriate for patients suspected of having cervical disk disease or spinal cord disease.

Electromyography (EMG) is unreliable and does not provide objective evidence of TOS.