Diseases of the Spinal Cord¶
Chapter 453 | Part 13: Neurologic Disorders
KEY CLINICAL POINTS¶
- Spinal cord diseases are devastating and often reversible if diagnosed early; prompt management is critical.
- Key differentials include compressive causes (e.g., tumors, abscesses) vs. noncompressive (e.g., MS, NMO, infections).
- MRI is essential for localization, while CSF analysis and lumbar puncture help distinguish inflammatory vs. infectious etiologies.
- Treatment varies by etiology: corticosteroids for inflammation, surgery for compression, and antivirals for infections.
- Prognosis depends on lesion level and completeness; high cervical injuries have worse outcomes.
1. DEFINITION & OVERVIEW¶
Spinal cord diseases encompass a wide range of conditions causing motor, sensory, and autonomic dysfunction. They are often devastating, with potential for irreversible damage if untreated. The spinal cord contains most of the motor and sensory pathways for the trunk and limbs, making it a critical structure. Early diagnosis and intervention are crucial to prevent long-term disability.
Table 453-2 Spinal Cord Levels Relative to the Vertebral Bodies¶
| SPINAL CORD LEVEL | CORRESPONDING VERTEBRAL BODY |
|---|---|
| Upper cervical | Same as cord level |
| Lower cervical | 1 level higher |
| Upper thoracic | 2 levels higher |
| Lower thoracic | 2–3 levels higher |
| Lumbar | T10–T12 |
| Sacral | T12–L1 |
1.1 Spinal Cord Anatomy¶
The spinal cord is ~46 cm long, with 31 segments. It is surrounded by the vertebral column and protected by meninges. The white matter contains ascending sensory and descending motor tracts, while the gray matter houses neuronal cell bodies. The spinal cord terminates at the conus medullaris, with the filum terminale extending to the coccyx.
1.2 Clinical Significance¶
Spinal cord injuries can lead to paraplegia, quadriplegia, sensory deficits, and autonomic dysfunction. The severity depends on the level and completeness of the lesion. Early recognition and treatment are critical to prevent irreversible damage.
2. EPIDEMIOLOGY¶
Spinal cord diseases are relatively rare but have significant morbidity. Compressive causes (e.g., tumors, abscesses) are more common in adults, while infectious and inflammatory causes (e.g., MS, NMO) are more prevalent in younger populations. Risk factors include trauma, autoimmune disorders, and systemic infections.
2.1 Incidence and Prevalence¶
Compressive myelopathy is more common in adults, while inflammatory and infectious causes are more frequent in younger individuals. The incidence of spinal cord tumors is ~1–2 per 100,000 annually.
2.2 Risk Factors¶
Risk factors include trauma, autoimmune disorders (e.g., MS, SLE), infections (e.g., TB, syphilis), and metabolic conditions (e.g., vitamin B12 deficiency).
3. ETIOLOGY & PATHOPHYSIOLOGY¶
Spinal cord diseases arise from diverse etiologies, including compressive (tumors, abscesses), vascular (infarction), inflammatory (MS, NMO), infectious (viral, bacterial), and metabolic (vitamin deficiencies) causes. Pathophysiology involves direct damage to neural tissue, inflammation, or disruption of spinal cord pathways.
Table 453-1 Treatable Spinal Cord Disorders¶
| CATEGORY | CONDITIONS |
|---|---|
| Compressive | Epidural abscess, intramedullary tumors, spinal stenosis |
| Inflammatory | Multiple sclerosis, neuromyelitis optica, sarcoidosis |
| Infectious | Tuberculosis, syphilis, HIV, viral myelitis |
| Metabolic | Vitamin B12 deficiency, subacute combined degeneration |
| Vascular | Spinal cord infarction, arteriovenous malformations |
3.1 Compressive Causes¶
Tumors, abscesses, herniated discs, and spinal stenosis cause mechanical compression, leading to ischemia, necrosis, and loss of function.
3.2 Inflammatory and Autoimmune Causes¶
Conditions like MS, NMO, and sarcoidosis involve immune-mediated attack on spinal cord tissue, leading to demyelination and inflammation.
3.3 Infectious Causes¶
Bacterial, viral (e.g., HSV, HIV), fungal, and parasitic infections can invade the spinal cord, causing direct damage and inflammation.
4. CLINICAL FEATURES¶
Clinical presentation varies by etiology and lesion location. Common features include sensory loss (pain, temperature), motor weakness, bladder/bowel dysfunction, and autonomic disturbances. Specific syndromes like Brown-Séquard, central cord, and anterior cord syndromes are recognized.
4.1 Sensory and Motor Deficits¶
Sensory loss typically affects pain and temperature (spinothalamic tract), while vibration and proprioception are preserved in some cases. Motor weakness may be asymmetric or spastic.
4.2 Autonomic Dysfunction¶
Bladder and bowel dysfunction, sexual dysfunction, and Horner’s syndrome (ptosis, miosis) may occur due to autonomic pathway involvement.
5. DIFFERENTIAL DIAGNOSIS¶
Differential diagnosis includes multiple sclerosis, neuromyelitis optica, spinal tumors, infections, and metabolic disorders. Key features like sensory level, motor patterns, and CSF findings help distinguish these conditions.
5.1 Inflammatory vs. Infectious Causes¶
Inflammatory conditions (e.g., MS) often present with bilateral sensory loss and CSF pleocytosis, while infections (e.g., TB) may show elevated CSF protein and oligoclonal bands.
5.2 Compressive vs. Noncompressive Causes¶
Compressive causes (e.g., tumors) may present with progressive weakness, while noncompressive causes (e.g., MS) often have relapsing-remitting patterns.
6. INVESTIGATIONS & DIAGNOSIS¶
MRI is the gold standard for imaging spinal cord lesions. CSF analysis, lumbar puncture, and blood tests help identify infectious, inflammatory, or metabolic causes. Electrodiagnostic studies and evoked potentials may aid in diagnosis.
Table 453-3 Considerations in the Evaluation of Myelopathy¶
| CATEGORY | TESTS |
|---|---|
| Imaging | MRI with/without contrast, CT myelogram |
| CSF Studies | Cell count, protein, glucose, oligoclonal bands |
| Infection Screening | Blood cultures, PCR for pathogens |
| Autoimmune Testing | Anti-AQP-4, anti-MOG, ANA, ENA |
| Vascular Evaluation | MRI, spinal angiogram |
6.1 Imaging¶
MRI with and without contrast is essential to identify tumors, abscesses, and inflammatory lesions. CT may be used for spinal trauma or calcifications.
6.2 CSF and Laboratory Tests¶
CSF analysis reveals pleocytosis, oligoclonal bands, and elevated protein in inflammatory conditions. Blood tests for infections, autoimmune markers, and metabolic panels are critical.
7. MANAGEMENT & TREATMENT¶
Treatment depends on the underlying cause. Compressive lesions require surgery or radiation, while inflammatory conditions are managed with corticosteroids and immunosuppressants. Antivirals, antibiotics, and supportive care are critical for infections and metabolic disorders.
7.1 Compressive Myelopathy¶
Decompression via laminectomy or discectomy is the mainstay. Radiotherapy or surgery for tumors, and antibiotics for infections.
7.2 Inflammatory and Autoimmune Causes¶
Corticosteroids (e.g., dexamethasone 10 mg IV) and immunosuppressants (e.g., azathioprine, rituximab) are used. Plasma exchange may be indicated for severe cases.
8. PROGNOSIS & COMPLICATIONS¶
Prognosis varies by etiology and lesion severity. Complete high cervical lesions have the worst outcomes, while lower spinal injuries may allow partial recovery. Complications include spasticity, contractures, and secondary infections.
Table 453-4 Expected Neurologic Function Following Complete Cord Lesions¶
| LEVEL | SELF-CARE | TRANSFERS | MAXIMUM MOBILITY |
|---|---|---|---|
| High quadriplegia (C1–C4) | Dependent on others; requires respiratory support | Dependent on others | Motorized wheelchair |
| Low quadriplegia (C5–C8) | Partially independent with adaptive equipment | May be dependent or independent | Manual wheelchair, drive automobile with aids |
| Paraplegia (below T1) | Independent | Independent | Ambulates short distances with aids |
8.1 Recovery Potential¶
Early intervention improves outcomes. Recovery is often incomplete, with residual weakness or sensory deficits. Spasticity and autonomic dysfunction are common long-term complications.
8.2 Long-Term Management¶
Rehabilitation, physical therapy, and management of complications (e.g., urinary tract infections, pressure sores) are essential for quality of life.
9. SPECIAL CONSIDERATIONS¶
Special populations require tailored management. Pregnancy, pediatric cases, and elderly patients may have unique risks and treatment considerations. For example, spinal cord injury in pregnancy may require cesarean delivery to prevent complications.
9.1 Pregnancy¶
Spinal cord injury during pregnancy may require cesarean delivery to prevent maternal and fetal complications. Radiation and certain medications are contraindicated.
9.2 Pediatrics¶
Pediatric spinal cord injuries often result from trauma or congenital abnormalities. Early surgical intervention is critical to prevent long-term disability.
10. KEY POINTS & CLINICAL PEARLS¶
- MRI is essential for localization and diagnosis of spinal cord lesions. 2. Corticosteroids (e.g., dexamethasone) are first-line for inflammatory causes. 3. Compressive lesions require urgent decompression. 4. Early treatment improves outcomes for infectious and autoimmune conditions. 5. Rehabilitation and long-term management are critical for functional recovery.