Thoracic Outlet Syndrome in Emergency Medicine Clinical Presentation

Updated: Mar 04, 2014
  • Author: Andrew K Chang, MD, MS; Chief Editor: Erik D Schraga, MD  more...
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Presentation

History

Neurologic symptoms occur in 95% of cases of thoracic outlet syndrome. The lower 2 nerve roots of the brachial plexus, C8 and T1, are most commonly (90%) involved, producing pain and paresthesias in the ulnar nerve distribution.

The second most common anatomic pattern involves the upper 3 nerve roots of the brachial plexus, C5, C6, and C7, with symptoms referred to the neck, ear, upper chest, upper back, and outer arm in the radial nerve distribution.

Neurologic TOS

Symptoms are most often those of nerve irritation and include the following:

  • Pain, particularly in the medial aspect of the arm, forearm, and the ring and small digits
  • Paresthesias, often nocturnal, awakening the patient with pain or numbness. Most often involves all 5 fingers but usually most noticeable in the fourth and fifth fingers and the ulnar forearm.
  • Weakness
  • Cold intolerance
  • Neck pain, pain over the trapezium, anterior chest wall pain, and occipital headache may also occur.
  • Raynaud phenomenon, hand coldness, and color changes may also be seen, usually due to an overactive sympathetic nervous system as opposed to ischemia.
  • Most have a history of neck trauma preceding their symptoms, most commonly from auto accidents and repetitive stress at work.

Venous TOS

Symptoms are those of an obstructed vein and include the following:

  • Swelling of the arm
  • Paresthesias in the fingers and hand (may be secondary to swelling as opposed to nerve compression)
  • Pain, often in younger men and often preceded by excessive activity in the arms

Arterial TOS

Symptoms are those of digital and hand ischemia and include the following:

  • Pain
  • Pallor
  • Coldness
  • Paresthesias
  • Often in young adults with a history of vigorous arm activity
  • Symptoms usually develop spontaneously from arterial emboli.
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Physical

In most cases, the physical examination findings of thoracic outlet syndrome (TOS) are completely normal. Other times, the examination is difficult because the patient may guard the extremity and exhibit giveaway-type weakness. The sensory examination is often unreliable.

Provocative testing

Provocative tests, such as the Adson, costoclavicular, and hyperabduction maneuvers, are unreliable. Approximately 92% of asymptomatic patients have variation in the strength of the radial pulse during positional changes.

Elevated arm stress test

The elevated arm stress test (EAST) is of debatable use, but it may be the most reliable screening test. It evaluates all 3 types of thoracic outlet syndrome (TOS).

To perform this test, the patient sits with the arms abducted 90 degrees from the thorax and the elbows flexed 90 degrees. The patient then opens and closes the hands for 3 minutes.

Patients with TOS cannot continue this for 3 minutes because of reproduction of symptoms. Patients with carpal tunnel syndrome experience dysesthesias in the fingers, but do not have shoulder or arm pain.

Upper limb tension test of Elvey

The upper limb tension test of Elvey may be helpful. This test serially puts tension on the brachial plexus similar to straight leg raising in the lower extremity.

Neurologic evaluation

Findings include the following:

  • A typical patient is a young, thin female with a long neck and drooping shoulders.
  • A positive EAST test result and the presence of a radial pulse are strong indicators of neurologic involvement of the brachial plexus.
  • Supraclavicular tenderness may be present.
  • Usually, no evidence of muscle atrophy is present, although the classic finding is known as the Gilliatt-Sumner hand, with the most dramatic atrophy in the abductor pollicis brevis, with lesser involvement of the interossei and hypothenar muscles.
  • Paresthesias/sensory loss is restricted to the ulnar aspect of the hand and forearm.
  • Weakness (usually subtle) of affected limb may be noted.

Venous evaluation

Findings include the following:

  • Edema of the upper extremity
  • Cyanosis of the upper extremity
  • Distended superficial veins of the shoulder and chest

Arterial evaluation

Findings include the following:

  • Pallor and pulselessness
  • Coolness on the affected upper extremity
  • Lower blood pressure in affected arm of greater than 20 mm Hg (a reliable indicator of arterial involvement)
  • Rarely can produce multiple small infarcts on the hand and fingers (embolization)
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Causes

Listed below are common etiologies for each anatomic form of thoracic outlet syndrome (TOS):

  • Neurogenic TOS: Etiology is most often a hyperextension neck injury, such as whiplash after a motor vehicle accident or a fall. [2] Other causes include repetitive injury most often form sitting at a keyboard for long hours.
  • Venous TOS: Etiology is obstruction of the subclavian vein, either thrombotic or nonthrombotic. [2] The cause is a combination of predisposing and precipitating factors. The predisposition is congenital anatomic narrowing at the point where the subclavian and jugular veins join to form the innominate vein. The precipitating factor that leads to thrombosis is excessive activity of the arm such as throwing a baseball, swimming, weight lifting, or working with the arms elevated. Coagulopathies can also be a precipitating cause.
  • Arterial TOS: Etiology is subclavian artery stenosis or aneurysm with thrombus formation and distal emboli usually due to a cervical rib or anomalous first rib. [2] The aneurysm and stenosis are usually asymptomatic until embolization occurs.
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