Cervical Spinal Cord Disease

Etiology of Both High Cervical (Above C3) or Mid-Low Cervical (C3-C8) Spinal Cord Disease

  • Cervical Spine Trauma with Cord Injury:
  • Cervical Space-Occupying Lesions: epidural abscess, hematoma, tumor, gumma, echinococcal cyst, etc
  • Cervical Disk Disease with Cord Compression
  • Diastematomyelia: bony spur in spinal canal, which may compress cervical spinal cord
  • Syringomelia: cavitation of central cord
  • Spondylolisthesis/Cervical Spondylosis
  • Cervical Osteoarthritis:
  • Atlanto-Axial Subluxation: associated with RA
  • Cervical Spinal Cord Infarction (see [[Spinal Cord Infarction]])
  • Post-Cervical Cordotomy: procedure done to achieve pain control may damage ascending and descending tracts
  • Transverse Myelitis (see [[Transverse Myelitis]])
  • Thoracic Outlet Syndrome

Physiology

High Cervical (Above C3) Spinal Cord Disease

  • Pulmonary HTN due to cervical cord disease (hypoventilation: hypoxia/ acidosis with pulmonary vasoconstriction)
  • Neck muscles serve to increase the upper rib cage A-P diameter (pull the sternum cranially)

Mid-Low Cervical (C3-C8) Spinal Cord Disease

  • Pulmonary HTN due to cervical cord disease (hypoventilation: hypoxia/acidosis with pulmonary vasoconstriction)
  • Neck muscles serve to increase the upper rib cage A-P diameter (pulls the sternum cranially)
  • Supine: pushes viscera against diaphragm (decreases RV, FRC, and TLC/ increases MIP, VC)
  • Upper rib cage moves paradoxically inward with inspiration (counteracted by action of scalene muscles)
  • Work of breathing is moderately elevated (due to decreased compliance of abdominal viscera: more pronounced in sitting position)

Diagnosis

High Cervical (Above C3) Spinal Cord Disease

  • ABG
    • Hypercapnia
    • Hypoxemia (A-a gradient may be elevated)
  • PFT’s (restrictive):
    • Variable VT (60-500 mL)
    • Decreased VC (<20% predicted)
    • Decreased expiratory reserve volume (usually close to zero, due to exp-iratory muscle weakness)
    • RV and FRC are about equal (due to absent tone of chest wall/ atelectasis)
    • Decreased TLC
    • Decreased MVV
    • Decreased MIP and MEP
    • Normal VD/VT
    • Normal DLCO
  • EMG/NCV: normal

Mid-Low Cervical (C3-C8) Spinal Cord Disease

  • ABG
    • Normocapnia (usually) or hypercapnia
    • Hypoxemia (A-a gradient may be elevated)
  • PFT’s (restrictive):
    • Decreased VC (typically 52% predicted)
    • Increased RV (with ERV decreased at about 21% predicted, due to expiratory muscle weakness) with normal FRC
    • Decreased TLC
    • Decreased MVV
    • Decreased MIP (typically: 60% predicted) and decreased MEP (typically: 30% predicted): inspiratory/expiratory deficits correlate poorly with the level of cord injury (due to irregular distri-bution of injury to cord/ prior or injury-induced pulmonary abnormalities/ partial recovery of function/ recruitment of muscles that do not nor-mally have phasic respiratory function/ variabil-ity in functional status of non-paralyzed muscles)
    • Decreased compliance (normal specific compliance)
    • Normal VD/VT
    • Normal DLCO
  • EMG/NCV: normal

Clinical

High Cervical (Above C3) Spinal Cord Disease

  • Symptoms/signs: disruption of reticulospinal pathways with nearly complete respiratory muscle paralysis (resembles central alveolar hypoventilation) with quadriplegia
    • Lesions that only affect the more lateral corticospinal pathways spare automatic control of breathing (but disrupt voluntary control)
    • Asphyxia/ dyspnea/ flaccid abdominal muscles
  • Pneumonia (due to impaired cough, etc.)
  • Acute/Chronic Hypoventilation (see Acute Hypoventilation, [[Acute Hypoventilation]] and Chronic Hypoventilation, [[Chronic Hypoventilation]])
  • Pulmonary Hypertension/Cor Pulmonale

Mid-Low Cervical (C3-C8) Spinal Cord Disease

  • Symptoms/signs: quadriplegia
    • Inspiratory muscle function is somewhat better than that in high cervical cord lesions
    • Expiratory muscle function (with cough) is partially preserved (because clavicular head of pectoralis muscle and cranial portion of serratus anterior can provide some expiratory muscle function)
  • Aspiration Pneumonia
  • Acute/Chronic Hypoventilation (see Acute Hypoventilation, [[Acute Hypoventilation]] and Chronic Hypoventilation, [[Chronic Hypoventilation]])
  • Pulmonary Hypertension/Cor Pulmonale

Treatment and Prognosis

High Cervical (Above C3) Spinal Cord Disease

  • Mechanical ventilation
  • Phrenic nerve pacing: see above
  • Glossopharyngeal breathing: see below
  • Secretion management: see below (under ALS)
  • Isometric pectoralis training: improves expiratory muscle function in quadriplegic patients

Mid-Low Cervical (C3-C8) Spinal Cord Disease

  • Spontaneous recovery in first 1 year after injury (15-40% mortality rate in the first year, mostly due to respiratory failure)
  • Control secretions/incentive spirometry/ etc. decrease mortality
  • Inspiratory muscle training: proven benefit
  • Mechanical ventilation: usually not necessary

References

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