Thoracic outlet syndrome (TOS) remains a diagnostic enigma in general practice. Although it is an uncommon cause of upper limb symptoms, its potential to cause chronic pain and disability means it should be considered when more common conditions do not fit the clinical picture. In primary care, management should be optimised to limit specialist referrals to those who truly need them. TOS has three subtypes: neurogenic (nTOS); venous (vTOS); and arterial (aTOS). Over 90% of cases are neurogenic (brachial plexus compression),1 whereas the vascular subtypes are far rarer but can present acutely and require urgent management. Vascular cases are typically referred directly to vascular surgery, whereas nTOS often follows an insidious course with symptoms that are subtle, non-specific, and easily misattributed to other conditions.2
When to suspect thoracic outlet syndrome
Patients with nTOS often present with arm numbness, a sense of heaviness or fatigue, diffuse arm ache, and tingling in the hand. Symptoms are usually worse with elevation of the arms or sustained overhead activity. This picture is easily mistaken for cervical radiculopathy, carpal tunnel syndrome, or shoulder pathology. However, nTOS symptoms do not conform to a single dermatome or nerve distribution, and they may fluctuate with changes in posture.3 Recognising this atypical pattern is key to considering TOS as a diagnosis when more common explanations have been ruled out.
Making a diagnosis of TOS in primary care is challenging. There are no universally accepted diagnostic criteria,4 so it is largely a diagnosis of exclusion. ‘Couch-side’ provocation manoeuvres such as the Roos test (elevated arm stress test) or Adson’s test can reproduce the patient’s symptoms and support the clinical impression, but these tests have a …
