What is Myelopathy?
Myelopathy refers to any pathologic process affecting the spinal cord, representing a clinical diagnosis based on signs and symptoms of spinal cord dysfunction 1.
Core Definition
Myelopathy is an umbrella term that encompasses diverse disease processes impacting the spinal cord itself, leading to neurological deficits. The term differs from "myelitis"—while both indicate spinal cord involvement, myelopathy does not imply a specific etiology, whereas myelitis specifically refers to inflammatory diseases of the spinal cord 2.
Clinical Presentation
The diagnosis rests on recognizing a constellation of symptoms consistent with central nervous system pathology involving the trunk, arms, and legs while generally sparing the head 3. Key clinical features include:
Motor Symptoms
- Sudden weakness and paralysis
- Clumsiness and loss of fine motor control
- Fatigability
- Acute paraparesis or quadriparesis (depending on spinal level involved) 1
Sensory Symptoms
- Paresthesias (abnormal sensations)
- Numbness or "deadness"
- Dysesthesias (unpleasant abnormal sensations)
Other Cardinal Features
- Pain over the lesion site (one of the cardinal complaints) 3
- Bladder dysfunction
- Bowel dysfunction
Etiologic Categories
Myelopathy can arise from primary intrinsic disorders of the spinal cord and includes 1:
Noninflammatory Causes
Extrinsic compression (most common in acute settings):
- Degenerative disease (spondylotic myelopathy)—most prevalent in cervical spine
- Disc herniations
- Epidural abscess or hematoma
- Primary or metastatic tumors
- Vertebral fractures with retropulsion
Vascular pathologies:
- Spinal cord ischemia (atheromatous disease, aortic surgery complications)
- Arteriovenous malformations
- Hematomyelia
Inflammatory Causes
- Demyelinating diseases (multiple sclerosis, neuromyelitis optica, acute disseminated encephalomyelitis)
- Systemic inflammatory conditions (lupus, Sjögren syndrome, Behçet disease, sarcoidosis)
- Infectious diseases
Other Causes
- Neoplastic (intramedullary tumors)
- Neurodegenerative
- Nutritional (subacute combined degeneration)
- Radiation-induced
- Idiopathic 1
Temporal Classification
Myelopathy presentations are categorized by symptom onset, which aids differential diagnosis 4:
- Hyperacute: Immediate onset
- Acute/Subacute: Days to weeks
- Chronic: Months to years
Each temporal pattern carries distinct prognoses and narrows the differential diagnosis.
Diagnostic Approach
MRI is now the mainstay in the evaluation of myelopathy because of its superb contrast resolution of the spinal cord 1. The first critical step must be excluding spinal cord compression, as this represents a surgical emergency 5, 6.
Key Diagnostic Considerations
- Physical examination may localize the myelopathic level, but imaging the entire spine may be beneficial even with localized findings 1
- Brain MRI may serve as a useful adjunct in certain cases 1
- About 40% of acute transverse myelopathies may show no MRI abnormalities despite high sensitivity 2
Common Pitfall
The most frequent etiology is degenerative disease of the spine causing compression from osteophyte or extruded disc material in the cervical or thoracic spine 6. However, clinicians must maintain vigilance for emergent causes requiring immediate imaging: extradural masses from metastatic disease, trauma, or epidural abscess 6, 3.