Diseases of the Spinal Cord¶

Chapter 453 | Part 13: Neurologic Disorders · Part 13 – Neurologic Disorders · Chapter 453

Key Clinical Points¶

The hallmark of a spinal cord lesion is a horizontally defined sensory level below which motor, sensory, and autonomic functions are impaired.
MRI with gadolinium is the primary initial diagnostic tool to rule out treatable compressive causes (tumor, abscess, hematoma).
Neoplastic compression typically presents first with pain that worsens with movement, coughing, or sneezing, often occurring at night.
Spinal epidural abscess presents with midline back/neck pain, fever, and progressive limb weakness; the duration of pain prior to presentation is generally ≤2 weeks.
Spinal cord infarction (anterior spinal artery) causes paraplegia/quadriplegia with dissociated sensory loss (loss of pain/temperature, preservation of vibration/position).
Steroid treatment (Dexamethasone 10 mg IV) should be administered before imaging if compression is suspected.
Epidural abscess requires decompressive laminectomy with debridement and long-term antibiotics (6–8 weeks); empiric therapy includes vancomycin, ceftriaxone, and metronidazole.
Motor recovery prognosis: Improvement is unlikely after 12 hours of established deficit; substantial recovery is poor after 48 hours.
Sacral sparing (preservation of perineal/sacral sensation) suggests an intramedullary lesion, while early sacral loss suggests an extramedullary lesion.
Specific syndromes like Brown-Séquard, Central Cord, and Anterior Cord Syndrome provide critical clues to the site and nature of the injury.

DEFINITION & OVERVIEW¶

• Clinical Significance: Spinal cord diseases are critical neurologic emergencies. • Impact: Because the spinal cord contains nearly all motor output and sensory input for the trunk and limbs in a small cross-sectional area, lesions cause devastating quadriplegia or paraplegia. • Reversibility: Many conditions are reversible if recognized and treated early; rapid diagnosis is essential.

ETIOLOGY & PATHOPHYSIOLOGY¶

Anatomy & Organization¶

• Structure: The spinal cord is a ~46 cm long, oval-shaped structure ending at the conus medullaris (lumbar level). • Segments: 31 segments; each defined by an exiting ventral motor root and entering dorsal sensory root. • Tracts: ◦ Lateral and ventral spinothalamic tracts: Ascend contralaterally to the side of the body innervated. ◦ Lateral corticospinal (pyramidal) tract: Lacks strict somatotopic organization in the spinal cord. • Intramedullary vs. Extramedullary: ◦ Intramedullary: Arise within the cord substance; produce poorly localized burning pain and often feature 'sacral sparing'. ◦ Extramedullary: Lie outside the cord; cause radicular pain, early sacral loss, and spastic weakness.

Vascular Supply¶

• Primary Vessels: ◦ Anterior spinal artery: Supplies anterior two-thirds of the cord. ◦ Posterior spinal arteries: Supply posterior columns (less distinct below midthoracic level). • Critical Zones: ◦ Artery of Adamkiewicz: Provides radicular supply at T11–L2. ◦ Risk Zone: The area between anterior and posterior artery territories, especially at T3–T4, is prone to infarction during hypotension or aortic clamping.

CLINICAL FEATURES¶

Localization of Lesions¶

• Sensory Level: The hallmark is a horizontally defined level below which sensory, motor, and autonomic functions are impaired. ◦ Mechanism: Damage to spinothalamic tract on the opposite side (one to two segments higher for unilateral lesions). • Motor Deficits: Lesions transecting descending corticospinal tracts cause upper motor neuron syndrome (paraplegia/quadriplegia, hyperreflexia, Babinski signs, spasticity). • Autonomic Dysfunction: Includes absent sweating below the lesion and bladder, bowel, and sexual dysfunction. • Spinal Shock: Acute transverse lesions may initially present with areflexic paralysis; this state lasts days to weeks and can be mistaken for anterior horn cell damage.

Specific Level Localization¶

• Cervical Cord: ◦ High level: Quadriplegia and diaphragm weakness. ◦ C5–C6: Reflex loss in biceps. ◦ C7: Reflex loss in finger/wrist extensors and triceps. ◦ C8: Reflex loss in finger/wrist flexion. ◦ Note: Horner's syndrome may occur at any cervical level. • Thoracic Cord: ◦ Markers: Nipples (T4) and Umbilicus (T10). ◦ Beevor's sign: T9–T10 lesions paralyze lower but not upper abdominal muscles, causing upward movement of the umbilicus during contraction. • Lumbar Cord: ◦ L2–L4: Paralyze flexion/adduction of thigh; weaken knee extension; abolish patellar reflex. ◦ L5–S1: Paralyze movements of the foot and ankle, flexion at the knee, and extension of the thigh; abolish the ankle jerks (S1). • Sacral/Conus Medullaris: ◦ Conus Syndrome: Bilateral saddle anesthesia (S3–S5), prominent bladder/bowel dysfunction, and impotence. Bulbocavernosus (S2–S4) and anal (S4–S5) reflexes are absent. ◦ Cauda Equina: Characterized by radicular pain, asymmetric weakness, and areflexia; bowel/bladder function is relatively spared.

Special Patterns of Spinal Cord Disease¶

• Brown-Séquard Hemicord Syndrome: ◦ Ipsilateral: Weakness (corticospinal) and loss of joint position/vibration (posterior column). ◦ Contralateral: Loss of pain/temperature (spinothalamic) one to two levels below lesion. • Central Cord Syndrome: ◦ Cervical level: Arm weakness out of proportion to leg; 'cape' distribution of sensory loss (pain/temp over shoulders, neck, upper trunk). ◦ Causes: Spinal trauma, syringomyelia, and intrinsic cord tumors. • Anterior Cord Syndrome: ◦ Cause: Anterior spinal artery occlusion. ◦ Findings: Loss of all functions except vibration and position sense; results from infarction at several contiguous levels. • Foramen Magnum Syndrome: ◦ Mechanism: Interruption of decussating pyramidal tract fibers. ◦ Pattern: 'Around-the-clock' progression (ipsilateral shoulder/arm → ipsilateral leg → contralateral leg → contralateral arm).

DIFFERENTIAL DIAGNOSIS¶

Compressive Myelopathies¶

• Neoplastic Compression: ◦ Common sites: Thoracic (most common); Sacral/Lumbar (prostate, ovarian cancer via Batson's plexus). ◦ Symptoms: Pain is usually the initial symptom; worsens with movement, coughing, or sneezing; often occurs at night. ◦ Imaging: MRI is superior to plain radiographs/bone scans for identifying extent and distinguishing from abscess/hematoma. • Spinal Epidural Abscess: ◦ Presentation: Midline back/neck pain, fever, and progressive limb weakness. ◦ Timing: Duration of pain prior to presentation is generally ≤2 weeks.

Noncompressive Myelopathies¶

• Spinal Cord Infarction: ◦ Mechanism: Occlusion of anterior spinal artery. ◦ Clinical: Rapidly progressive (hours) weakness/spasticity; dissociated sensory loss (pain/temp lost, vibration/position preserved). • Acute Spondylitic Myelopathy: ◦ Risk: Hyperextension injuries in patients with pre-existing degenerative cervical spine disease.

DIAGNOSTIC APPROACH¶

Initial Imaging: MRI of spinal cord with and without contrast (centered on suspected level; often imaged from cervical to sacral) to exclude compressive causes.
CSF Analysis: ◦ Parameters: Cell count, protein, glucose, IgG index/synthesis rate, oligoclonal bands, VDRL. ◦ Microbiology: Gram stain, acid-fast bacilli, India ink; PCR for VZV, HSV-1, HSV-2, EBV, CMV, HHV-6, enteroviruses, HIV; cultures (viral, bacterial, mycobacterial, fungal).
Blood Studies: ◦ Infection: HIV, RPR, Enterovirus antibodies, Mycoplasma pneumoniae, Borrelia burgdorferi. ◦ Specific Conditions: Anti-aquaporin-4, anti-MOG, anti-GFAP (for NMO); Serum ACE, Calcium levels (for Sarcoidosis).
Vascular Evaluation: MRI, CT myelogram, or spinal angiogram if infarction is suspected.
Additional Diagnostics: ◦ Multiple Sclerosis: Brain MRI, evoked potentials. ◦ Metabolic: Vitamin B12, copper, zinc.

MANAGEMENT & TREATMENT¶

Pre-treatment (if compression suspected): Administer glucocorticoids (Dexamethasone 10 mg IV) before imaging.
Neoplastic Compression Treatment: ◦ Surgery and/or radiotherapy. ◦ Prognosis: Improvement is unlikely if motor deficits are established >12 hours; substantial recovery is poor after 48 hours.
Spinal Epidural Abscess Treatment: ◦ Surgical: Decompressive laminectomy with debridement. ◦ Medical: Long-term antibiotics (6–8 weeks). ◦ Empiric Regimen: Vancomycin, ceftriaxone, and metronidazole.
Monitoring: Evaluate for progression of symptoms or development of complications.

PROGNOSIS & COMPLICATIONS¶

• Motor Recovery Timeframes: ◦ >12 hours: Improvement unlikely if motor deficits (paraplegia/quadriplegia) are established. ◦ >48 hours: Prognosis for substantial recovery is poor. • Neoplastic Survival: Most patients do not experience recurrence in the months following radiotherapy with survival beyond 2 years; recurrence becomes more likely after 2 years.

KEY PEARLS & HIGH-YIELD POINTS¶

• Sacral Sparing Rule: Intramedullary (e.g., tumor, syrinx) = Sacral sparing; Extramedullary (e.g., abscess, extra-medullary tumor) = Early sacral loss. • T1/T2 MRI Utility: T1 shows anatomy and marrow signal (hypointense in tumors); T2 highlights edema and inflammation. • Rapid Assessment: If radicular symptoms are present but no myelopathy is evident, imaging may be delayed 24–48 hours. • Clinical Markers: ◦ T4 = Nipples ◦ T10 = Umbilicus ◦ T3–T4 = Common site of infarction due to marginal blood flow.

TABLES¶

Table 453-1: Treatable Spinal Cord Disorders¶

• Compressive: Epidural/intradural/intramedullary neoplasm, epidural abscess, epidural hemorrhage, cervical spondylosis, herniated disk, posttraumatic compression, AVM, and hypercoagulable states. • Inflammatory: MS, Neuromyelitis optica, Sarcoidosis, SLE, Sjögren's, Behcet's, anti-MOG, anti-GFAP. • Infectious: Viral (VZV, HSV, CMV, HIV), Bacterial/Mycobacterial (Borrelia, Listeria, Syphilis, Mycoplasma), Parasitic (Schistosomiasis, Toxoplasmosis). • Developmental: Syringomyelia, Meningomyelocele, Tethered cord. • Metabolic: Vitamin B deficiency, Folate deficiency, Copper deficiency.

Table 453-2: Spinal Cord Levels Relative to the Vertebral Bodies¶

• 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

Table 453-3: Considerations in the Evaluation of Myelopathy¶

• Step 1: MRI with/without contrast (exclude compression). • Step 2: CSF studies (Cell count, protein, glucose, IgG index, VDRL, Gram's, Acid-fast, PCR for various viruses, cultures). • Step 3: Blood studies (HIV, RPR, Enterovirus, Mycoplasma, Borrelia, etc.). • Step 4: Vascular causes (MRI, CT myelogram, spinal angiogram). • Step 5-7: MS (Brain MRI), NMO (Aquaporin-4, MOG, GFAP), Sarcoidosis (ACE, Calcium, Chest CT, Gallium scan). • Step 8-10: Systemic immune (ANA, dsDNA, etc.), Paraneoplastic antibodies, Metabolic (B12, Copper, Zinc).

Table 453-4: Expected Neurologic Function Following Complete Cord Lesions¶

• High quadriplegia (C1–C4): ◦ Self-care: Dependent on others; requires respiratory support. ◦ Transfers: Dependent on others. ◦ Mobility: Motorized wheelchair. ◦ Note: Some may be partially independent with adaptive equipment. • Paraplegia (below T1): ◦ Self-care: Independent. ◦ Transfers: Independent. ◦ Mobility: Ambulates short distances with aids.

Reference Tables¶

TABLE 453-1 Treatable Spinal Cord Disorders Compressive¶

Harrison's 22e, p.3560

Compressive
Epidural, intradural, or intramedullary neoplasm
Epidural abscess
Epidural hemorrhage
Cervical spondylosis
Herniated disk
Posttraumatic compression by fractured or displaced vertebra or hemorrhage
Vascular
Arteriovenous malformation and dural fistula
Antiphospholipid syndrome and other hypercoagulable states
Inflammatory
Multiple sclerosis
Neuromyelitis optica
Sarcoidosis
Systemic immune-mediated disorders: SLE, Sjögren’s, Behcet’s disease, APL
antibody syndrome, others vasculitis
Other CNS disorders: anti-MOG, anti-GFAP, paraneoplastic,a CLIPPERS,
Erdheim-Chester
Infectious
Viral: VZV, HSV-1 and -2, CMV, HIV, HTLV-1, others
Bacterial and mycobacterial: Borrelia, Listeria, syphilis, others
Mycoplasma pneumoniae
Parasitic: schistosomiasis, toxoplasmosis, cysticercosis
Developmental
Syringomyelia
Meningomyelocele
Tethered cord syndrome
Metabolic
Vitamin B deficiency (subacute combined degeneration)
12
Folate deficiency
Copper deficiency

TABLE 453-2 Spinal Cord Levels Relative to the Vertebral Bodies¶

Harrison's 22e, p.3560

SPINAL CORD LEVEL	CORRESPONDING VERTEBRAL BODY
Upper cervical	Same as cord level
Upper thoracic	2 levels higher
Lumbar	T10–T12

TABLE 453-3 Considerations in the Evaluation of Myelopathy 1. MRI of spinal cord with and without contrast (exclude…¶

Harrison's 22e, p.3564

1. MRI of spinal cord with and without contrast (exclude compressive causes).
  2. CSF studies: Cell count, protein, glucose, IgG index/synthesis rate,
  oligoclonal bands, VDRL; Gram’s stain, acid-fast bacilli, and India ink stains;
  PCR for VZV, HSV-2, HSV-1, EBV, CMV, HHV-6, enteroviruses, HIV; antibody
  for HTLV-1, Borrelia burgdorferi, Mycoplasma pneumoniae, and Chlamydia
  pneumoniae; viral, bacterial, mycobacterial, and fungal cultures.
  3. Blood studies for infection: HIV; RPR; IgG and IgM enterovirus antibody;
  IgM WNV, group B arbovirus, mumps, measles, rubella, Brucella melitensis,
  Chlamydia psittaci, Bartonella henselae, schistosomal antibody; PCR and
  antigen tests for SARS-CoV-2; cultures for B. melitensis. Also consider nasal/
  pharyngeal/anal cultures for enteroviruses; stool O&P for Schistosoma ova.
  4. Vascular causes: MRI, CT myelogram; spinal angiogram.
  5. Multiple sclerosis: Brain MRI scan; evoked potentials.
  6. Neuromyelitis optica and related disorders: Serum anti-aquaporin-4
  antibody, anti-MOG antibody, anti-GFAP antibody.
  7. Sarcoidosis: Serum angiotensin-converting enzyme; serum Ca; 24-h urine
  Ca; chest x-ray; chest CT; slit-lamp eye examination; total-body gallium scan;
  lymph node biopsy.
  8. Systemic immune-mediated disorders: ESR; ANA; ENA; dsDNA; rheumatoid
  factor; anti-SSA; anti-SSB, complement levels; antiphospholipid and
  anticardiolipin antibodies; pANCA; antimicrosomal and antithyroglobulin
  antibodies; if Sjögren’s syndrome suspected, Schirmer test, salivary gland
  scintigraphy, and salivary/lacrimal gland biopsy.
  9. Paraneoplastic disorders: Antibody for amphiphysin, CRMP5, Hu, others.
  10. Other: vitamin B , copper, zinc.
  12

TABLE 453-4 Expected Neurologic Function Following Complete Cord Lesions LEVEL High quadriplegia (C1–C4) Low…¶

Harrison's 22e, p.3569

LEVEL	SELF-CARE	TRANSFERS	MAXIMUM MOBILITY
High quadriplegia (C1–C4)	Dependent on others; requires respiratory support	Dependent on others	Motorized wheelchair
	Partially independent with adaptive equipment	May be dependent or independent
Paraplegia (below T1)	Independent	Independent	Ambulates short distances with aids