What are the symptoms and diagnostic approach for a patient with suspected thoracic radiculopathy presenting with persistent left thoracic back numbness?

Thoracic Radiculopathy: Clinical Presentation and Diagnostic Approach

Thoracic radiculopathy presents with dermatomal pain radiating in a band-like distribution around the chest or abdomen, often with neuropathic characteristics such as burning or electric sensations, and requires MRI thoracic spine without IV contrast when symptoms persist or neurologic deficits are present. 1, 2

Clinical Symptoms

Pain Characteristics:

• Dermatomal distribution following a specific spinal nerve root pattern (T1-T12), commonly presenting as band-like pain wrapping around the chest wall or abdomen 2, 3
• Neuropathic quality with burning, electric, or shooting sensations rather than mechanical pain 2
• Radiating from the back to the anterior chest or abdominal wall in the affected dermatome 4, 3
• Pain typically originates in the thoracic back and radiates anteriorly, distinguishing it from visceral pathology 3

Sensory Manifestations:

• Numbness or paresthesias in the affected dermatome, as seen with persistent left thoracic back numbness 2, 4
• Sensory deficits occur in 61% of symptomatic cases 1, 2
• Dermatomal sensory loss that follows spinal nerve root innervation patterns rather than peripheral nerve territories 2

Motor and Autonomic Features:

• Motor weakness in the affected myotome (61% of symptomatic cases) 1
• Spasticity or hyperreflexia (58% of cases) 1
• Positive Babinski sign (55% of cases) 1
• Bladder dysfunction in severe cases (24% of cases) 1

Common Etiologies

Mechanical Compression:

• Thoracic disc herniation (most common below T7), frequently calcified (20-65%), occurring in patients aged 30-50 years, with one-third having trauma history 1, 5
• Foraminal stenosis from facet arthropathy or bony overgrowth 6
• Ossification of ligamentum flavum (particularly in Asian populations) 4
• Degenerative disc disease 7

Metabolic Causes:

• Diabetes mellitus is a frequent cause of thoracic radiculopathy 7, 3

Diagnostic Approach

Initial Clinical Assessment:

• Identify dermatomal pain pattern with or without sensory loss 2
• Examine for motor deficits, spasticity, hyperreflexia, positive Babinski sign, or bladder dysfunction 1, 2
• Assess for red flags: age >50 with cancer history, unexplained weight loss, fever, immunosuppression, IV drug use, age >65, chronic steroid use, or known osteoporosis 5, 2
• Distinguish from anginal chest pain by dermatomal pattern and provocation with spinal movement or positioning 2

Imaging Strategy:

• MRI thoracic spine without IV contrast is the initial imaging modality of choice when thoracic radiculopathy is clinically suspected 1, 2
• Urgent imaging (within 12 hours) if clinical suspicion of cord or cauda equina compression, particularly with positional symptoms 2
• Immediate MRI is mandatory if progressive neurological deficits or myelopathic signs are present 2
• CT myelography may be complementary to MRI for identifying specific compressive pathology and presurgical planning 1, 2
• Electromyography is useful in confirming radiculopathy and may show acute changes consistent with nerve root dysfunction 7, 3

Timing of Imaging:

• For acute thoracic back pain (<4 weeks) without red flags, myelopathy, or radiculopathy, imaging is not indicated 5
• For persistent symptoms with radiculopathy, imaging should be performed if the patient is a potential candidate for surgery or intervention 1

Critical Pitfalls

Do not delay imaging when:

• Progressive neurologic deficits develop 1, 2
• Myelopathic signs emerge (spasticity, hyperreflexia, positive Babinski, bladder dysfunction) 1, 2
• Red flags are present suggesting malignancy, infection, or fracture 5, 2

Avoid misdiagnosis:

• Thoracic radiculopathy presenting as abdominal pain may be mistaken for visceral pathology, leading to excessive testing and unnecessary surgery 3
• The dermatomal pattern and provocation by spinal movement distinguish it from cardiac or intra-abdominal causes 2, 3

Treatment Considerations

Conservative Management:

• Anti-inflammatory therapy combined with neuropathic pain medications (phenytoin, carbamazepine, amitriptyline) or local nerve blocks 3
• Conservative treatment is first-line for most cases 7, 6

Surgical Intervention:

• Reserved for progressive myelopathy, neurologic compromise, or failure of conservative treatment 4, 7, 6
• Surgical decompression provides immediate relief when conservative measures fail 4, 6