What are the most prominent presentations of thoracic outlet syndrome (TOS) in a middle-aged male?

Presentations of Thoracic Outlet Syndrome in Middle-Aged Males

The most prominent presentation of thoracic outlet syndrome (TOS) in middle-aged males is neurogenic compression manifestation, accounting for over 90% of all TOS cases. 1

Types of TOS Presentations

TOS can be classified into three distinct types based on the compressed structures:

1. Neurogenic TOS (NTOS) - Most common presentation (>90% of cases)

   • Symptoms include:
     • Upper extremity paresthesia
     • Pain in arm, shoulder, and neck
     • Weakness in the affected limb
     • Occipital headache
   • Physical findings: Positive provocative maneuvers including neck rotation, head tilting, upper limb tension test, and arm abduction 1

2. Venous TOS (vTOS)

   • Presents with:
     • Arm swelling
     • Cyanosis
     • Pain due to subclavian vein obstruction (with or without thrombosis)
   • Diagnostic findings: Venous thrombosis and collateral circulation detected in both neutral and stressed arm positions 2

3. Arterial TOS (aTOS) - Least common (<1% of cases)

   • Presents with:
     • Symptoms of arterial ischemia
     • Emboli from subclavian artery stenosis or aneurysms
     • Discoloration of the hand
     • Decreased pulses
   • Almost always associated with cervical rib or anomalous first rib on imaging 1

Diagnostic Considerations

When evaluating a middle-aged male with suspected TOS:

• Physical examination should assess for diminished radial pulse with provocative maneuvers and evaluate for muscle imbalances and postural abnormalities 3
• Multiple physical examination maneuvers should be performed due to insufficient sensitivity or specificity of individual tests:
  • Adson's Test
  • Wright's Test
  • Eden's Test 3
• A systolic blood pressure difference of more than 25 mmHg between arms is considered significant for potential arterial compression 3

Imaging Recommendations

The American College of Radiology recommends:

• Evaluation in both neutral and arms-abducted positions to demonstrate dynamic compression 3
• Dedicated MRI of the brachial plexus as the recommended imaging modality 3
• High-resolution T1-weighted and T2-weighted sequences in sagittal and axial planes 3
• For vascular TOS: CT venography, MRI/MRV, or duplex ultrasound 3

Common Pitfalls to Avoid

• Relying solely on the Adson Test for diagnosis - this has been shown to be of no clinical value and should not be used alone to diagnose any type of TOS 1
• Using only axial imaging slices, which can lead to misrepresentation of stenosis severity 3
• Misdiagnosing NTOS as "vascular" TOS - a common error given the predominance of neurogenic symptoms 1
• Failing to recognize that venous compression has been demonstrated in both asymptomatic and symptomatic populations when arms are abducted, requiring careful interpretation of imaging findings 2

Etiology in Middle-Aged Males

TOS in middle-aged males is commonly caused by:

• Neck trauma (particularly whiplash injuries) leading to scarred scalene muscles 1
• Repeated work stress 4
• Congenital abnormalities such as cervical ribs or fibrous bands 4
• First rib anomalies or cervical ribs 2

The prevalence of symptomatic TOS is estimated at 1-10 per 100,000 people 3, 4, making it a relatively rare condition that requires careful diagnostic evaluation.