Diagnosis of Thoracic Outlet Syndrome



Diagnosis of Thoracic Outlet Syndrome



Chandu Vemuri and Robert W. Thompson


The clinical presentation of the thoracic outlet syndrome (TOS) depends on the specific structures compressed, giving rise to three distinct conditions: neurogenic TOS, venous TOS, and arterial TOS. All three types are rare conditions, and diagnosis dependd on clinical suspicion, pattern recognition, and exclusion of more common diseases that have overlapping features. A provisional diagnosis can usually be made or excluded on the basis of clinical history, description of symptoms, and physical examination, supplemented by a limited number of diagnostic studies.



Neurogenic Thoracic Outlet Syndrome


An accurate diagnosis of neurogenic TOS remains a significant challenge, yet properly identified patients respond quite well to treatment. A set of provisional criteria exist for the clinical diagnosis of neurogenic TOS (Box 1).



BOX 1   Provisional Criteria for the Clinical Diagnosis of Neurogenic Thoracic Outlet Syndrome









Clinical Presentation


The symptoms of brachial plexus nerve root compression consist of pain, numbness, and paresthesias in the neck, shoulder, arm, and hand. These symptoms can be variable throughout the day and can differ day to day, depending on levels of activity. Symptoms are also typically dynamic, with marked positional exacerbation during arm abduction, elevation, and other maneuvers. Some patients with neurogenic TOS experience arm or hand weakness, overt electrophysiologic abnormalities of the brachial plexus, and thenar or hypothenar muscle atrophy (Gilliatt-Sumner hand). Although this clinical presentation has been termed true neurogenic TOS, these findings might simply represent an advanced form of neurogenic TOS with long-standing and possibly irreversible nerve injury. In contrast, most patients with neurogenic TOS exhibit varying degrees of sensory symptoms with no hand weakness or muscle atrophy and with normal or nonspecific findings on conventional electrophysiologic testing and/or imaging studies. Symptoms often develop gradually in patients with neurogenic TOS, and they can have either acute exacerbations or a steady progression with increasing disability. Although the dominant extremity is often more symptomatic at first presentation, the opposite extremity can become involved over time, perhaps as a result of compensatory overuse in protecting the affected extremity.


Headache is a common but often overlooked symptom of neurogenic TOS. This may be caused by a secondary spasm within the upper trapezius and paraspinous muscles, causing pain referred to the back of the neck and head. Headaches associated with this type of TOS are typically occipital, whereas frontal headaches are not specifically associated with brachial plexus compression. Although many patients also have migraine headache, there is no clear pathophysiologic association between these two conditions.


Upper extremity vasomotor disturbances can accompany neurogenic TOS, particularly in those with long-standing or severe symptoms, resulting in cold sensations or intermittent discoloration in the hands and fingers. This finding should be distinguished from positional dampening or ablation of the radial pulse with arm elevation, a common finding in patients with TOS and unaffected persons that does not imply the presence of functional arterial insufficiency. Rather, the microvascular vasomotor disturbances accompanying neurogenic TOS are thought to arise from transient upper extremity sympathetic overactivity associated with brachial plexus nerve irritation.


In more advanced situations these symptoms have progressed to resemble those of complex regional pain syndrome (CRPS), with persistent vasospasm, disuse edema, extreme hypersensitivity, and allodynia. The acuity of these symptoms often leads to avoidance and withdrawal from even light touch of the affected extremity. In most cases the diagnosis of associated CRPS can be made on clinical grounds, but it may be supported by vascular laboratory studies revealing abnormal vasoconstrictive responses in the cold-pressor test, imaging studies of the hand assessing the microcirculation and osseous changes, and cervical sympathetic (stellate) ganglion blocks. The identification of coexisting CRPS is quite important in patients with neurogenic TOS, because it can require different considerations for treatment.

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Aug 25, 2016 | Posted by in CARDIOLOGY | Comments Off on Diagnosis of Thoracic Outlet Syndrome

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