COMMON DIFFERENTIAL DIAGNOSES

TOS may present with a wide array of symptoms making it difficult to distinguish it from other neurological conditions in the upper extremity and the cervical spine. Differential diagnoses must be considered to avoid any potential misdiagnosis in practice to ensure the best quality treatment for patients (Fugate et al., 2009).

Cervical radiculopathy

The most common differential diagnosis that overlaps with TOS is cervical radiculopathy, which is caused by irritation or compression of the cervical nerve roots (e.g., osteophytes or a herniated disc) that follow a specific dermatomal pattern (Woods & Hilibrand, 2015).

Similarities between Cervical Radiculopathy and TOS

Cervical radiculopathy and TOS both lead to neurological symptoms such as tingling, weakness and numbness in the upper extremity. Both conditions affect the neck, shoulder, arm and hand (Iyer & Kim, 2016). In nTOS the compression of the brachial plexus C8-T1 can mimic C8 nerve root compression which is prevalent in cervical radiculopathy, causing possible misdiagnosis (Nichols, 2009).

Differences between Cervical Radiculopathy and TOS

TOS affects the brachial plexus trunks, whereas cervical radiculopathy impacts the nerve roots (Iyer & Kim, 2016). Furthermore, TOS affects the ulnar nerve distribution while cervical radiculopathy generally impacts a wider area of symptoms depending on the nerve roots involved (Caridi et al., 2011). Objective examination results are inherently different, with cervical radiculopathy depicting reduced neck range of motion (ROM) and a positive Spurling’s test. Cervical radiculopathy also does not commonly present with any vascular involvement, which is prevalent in TOS (Kang et al., 2020).

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Carpal Tunnel Syndrome (CTS)

CTS is one of the most commonly reported forms of medial nerve compression. The condition occurs when the median nerve is compressed as it travels through the wrist (Genova et al., 2020).

Similarities between CTS and TOS

Both CTS and TOS present with pain, tingling, and numbness in the hand and fingers. Symptoms are exacerbated by repetitive movements and patients are subject to weakness and muscle atrophy in the later stages of both conditions. Furthermore, both conditions originate via nerve compression and are aggravated by poor posture (Wipperman & Goerl, 2016).

Differences between CTS and TOS

The differences include the location of the nerve compression as CTS occurs in the carpal tunnel and TOS occurs at the thoracic outlet. The symptoms are also disparate as CTS affects the wrist and hand (Aboonq, 2015), whereas TOS begins in the neck or shoulder and refers down the anterior aspect of the posterior arm.

The distribution of symptoms is also quite distinct as CTS follows a median nerve distribution (thumb, index, middle finger), whereas TOS generally affects the ulnar nerve distribution (ring and small finger). CTS is often provoked by activities that involve prolonged wrist flexion, including typing or driving (Aboonq, 2015).

Physical examination is relatively dissimilar as CTS is provoked via Phalen’s Test and Tinel’s sign at the wrist (Padua et al., 2016).

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Rotator Cuff Pathology

The rotator cuff consists of four muscles, infraspinatus, supraspinatus, subscapularis, and teres minor. It is the primary dynamic stabiliser of the shoulder and is put under significant stress during contact sports and repetitive overhead movements (Blevins, 1997).

Similarities between Rotator Cuff Pathologies and TOS

Both conditions result in a clinical presentation of shoulder pain that worsens with repetitive movement, either above the head or with heavy lifting. The patient demographic include manual labourers, athletes, and office workers with poor postures in both conditions (Fitzpatrick et al., 2022).

Differences between Rotator Cuff Pathologies and TOS

In rotator cuff pathologies, pain generally originates on the lateral aspect of the shoulder, whereas the inception of TOS can also occur in the chest or neck. Rotator cuff conditions generally present without neurological symptoms or vascular involvement.

There is also a distinct contrast in the special tests undertaken during an assessment, with Hawkins-Kennedy, Neer’s impingement sign, Empty can test, and External rotation lag sign underpinning the basis of rotator cuff diagnosis (Fitzpatrick et al., 2022).

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Cubital Tunnel Syndrome

Cubital tunnel syndrome is the entrapment of the ulnar nerve as it passes the cubital tunnel at the elbow region (Palmer & Hughes, 2010).

Similarities between cubital tunnel syndrome and TOS

Both conditions consist of ulnar nerve compression. The two conditions also present with numbness, tingling, and pain in the arm which follows the ulnar nerve distribution into the hand. Both conditions are provoked via repetitive movements and can lead to weakness and muscle atrophy in the upper extremity (Palmer & Hughes, 2010).

Differences between cubital tunnel syndrome and TOS

Cubital tunnel entrapment occurs at the elbow whereas TOS occurs between the clavicle and first rib. Symptoms of cubital tunnel syndrome are generally localised to the hand (ring finger and pinky) and forearm, comparatively TOS originates in the neck or shoulder and radiates down the entire upper extremity. The causes of the conditions also differ with cubital tunnel syndrome attributed to prolonged elbow flexion which worsens with direct pressure at the elbow. Special tests are also contrasting, as cubital tunnel syndrome is provoked by Tinel’s sign, elbow flexion test and Froment’s sign (Staples & Calfee, 2017).

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Pancoast Tumour

A Pancoast tumour is a non-small cell lung cancer that forms at the apex of the lung on the anatomical groove formed by the subclavian artery, where the thoracic outlet is situated. Pancoast tumours infringe upon the brachial plexus, ribs, and vertebrae causing debilitating pain and neurological deficits (Rusch, 2006).

Similarities between Pancoast tumours and TOS

Both conditions cause neurological deficits and pain in the upper extremity, shoulder and neck. The C8-T1 nerve roots of the brachial plexus are generally involved in Pancoast tumours and TOS. Both conditions cause radiating pain down the distal aspects of the upper extremity (Panagopoulos et al., 2014).

Differences between Pancoast tumours and TOS

The most prominent differences between the two conditions include the systemic signs of malignancy that are prevalent with tumours. These include chronic fatigue, night sweats and fevers. Pancoast tumours also cause symptoms such as haemoptysis, dyspnoea and coughing (Panagopoulos et al., 2014). Pancoast tumours present with Horner’s syndrome, which is a neurological condition that occurs from sympathetic nerve damage in the face and eye. Horner’s syndrome causes ptosis (drooping eyelid), miosis (constricted pupils), anhidrosis on the affected side of the face (absence of sweating) and enophthalmos (sunken eye appearance) (Martin, 2018).

The arrow indicates a Pancoast tumour located at the Apex of the lung (Jones et al., 2019).

(LearnHaem, 2021)