What causes myelopathy in a patient with progressive weakness and numbness in their hands, likely related to cervical spine degeneration or a herniated disc?

What Causes Myelopathy

Degenerative cervical spine disease is the most common cause of myelopathy, particularly in the context of progressive hand weakness and numbness, with disc herniations, osteophyte formation, and spinal canal narrowing being the primary contributing factors. 1, 2

Primary Etiologic Categories

Compressive (Extrinsic) Causes

Degenerative/Spondylotic Disease (Most Common)

• Cervical spondylotic myelopathy represents the most frequent cause of spinal cord dysfunction in adults, accounting for the majority of chronic myelopathy cases 1, 3
• Contributing mechanisms include:
  • Disc herniations compressing the spinal cord anteriorly 4, 1
  • Osteophyte formation from posterior vertebral body edges 2, 5
  • Ligamentum flavum hypertrophy 5
  • Ossification of the posterior longitudinal ligament 6
  • Congenitally short pedicles that accentuate compression 4
• The cervical spine is predominantly affected due to its mobility and degenerative susceptibility 1, 2

Epidural Space Pathology

• Epidural abscess causes acute compression with severe back pain, fever, and rapidly progressive deficits 4, 2
• Epidural hematoma can develop spontaneously or post-traumatically 4
• Epidural lipomatosis represents a rarer compressive cause 1

Neoplastic Compression

• Metastatic epidural spinal cord compression affects 2.5-5% of cancer patients, with back pain occurring in 88-90% 2
• Primary or metastatic tumors in extradural and intradural extramedullary spaces cause progressive compression 4, 2

Post-Surgical Complications

• Seromas, pseudomeningoceles, hematomas, and epidural abscesses can develop throughout the postoperative course 4

Vascular Causes

Ischemic Myelopathy

• Most commonly results from atheromatous disease or complications of aortic surgery in adults 4, 2
• Additional predisposing factors include:
  • Systemic hypotension 4
  • Thoracoabdominal aneurysms or dissection 4
  • Sickle cell disease 4
  • Fibrocartilaginous embolic disease 4

Arteriovenous Malformations

• Spinal arteriovenous malformations can cause progressive myelopathy through venous hypertension 4, 2
• Intramedullary AVM or spinal artery aneurysm rupture rarely causes hematomyelia and acute myelopathy 4

Inflammatory and Demyelinating Causes

Multiple Sclerosis

• Involves the spinal cord in 80-90% of patients, most commonly affecting the cervical cord 2
• Presents with incomplete transverse myelitis, Lhermitte's sign, and asymmetric deficits 2

Neuromyelitis Optica

• Characterized by longitudinally extensive transverse myelitis with severe bilateral motor weakness 2

Other Inflammatory Conditions

• Systemic inflammatory diseases can cause myelopathy 4, 1

Infectious Causes

• Human T-cell lymphotropic virus myelitis 1
• Tuberculosis causing chronic compression 1, 2
• Schistosomiasis 2
• HIV vacuolar myelopathy 2

Metabolic Causes

• Vitamin B12 deficiency leading to subacute combined degeneration 1
• Copper deficiency myelopathy 1

Clinical Context for Your Patient

In a patient presenting with progressive hand weakness and numbness suggestive of cervical pathology, the differential diagnosis prioritizes:

1. Cervical spondylotic myelopathy as the leading diagnosis, given the progressive nature and hand involvement 3, 6
2. Cervical disc herniation causing acute-on-chronic compression 4, 1
3. Combined degenerative changes including osteophytes, disc disease, and ligamentous hypertrophy 6, 5

Critical Diagnostic Pitfall

The degree of radiographic abnormality may not correlate with symptom severity 1. Additionally, in patients aged 50-70 years, primary degenerative spinal cord lesions (amyotrophic lateral sclerosis, primary progressive spastic paralysis) can mimic compressive myelopathy, and age-appropriate degenerative spine changes are universal—leading to unnecessary surgery if compression is incorrectly attributed as causative 7. MRI with and without contrast is essential to distinguish compressive from non-compressive etiologies and to evaluate for inflammatory, infectious, or neoplastic causes 1, 2.