• Clinical science

Myelopathy

Abstract

Myelopathies are neurological disorders due to compression of the spinal cord. Myelopathies can be cervical, thoracic, or lumbar. Cervical myelopathy is the most common type of myelopathy in adults above 55 years of age. Etiologies include degenerative changes of the spine, spinal trauma, infection, tumors, and autoimmune disorders. Onset can be acute, step-wise, or insidious. Clinical features vary depending on the level of the lesion and include local pain, stiffness, and impaired sensation, hypotonia, and hyporeflexia at the level of the lesion, and spasticity and hyperreflexia below the level of the injury level. Diagnosis is confirmed by MRI or myelography. Treatment includes conservative management for degenerative disease or immediate surgical decompression in acute compression.

Etiology

References:[1]

Classification

  • Cervical myelopathy (most common cause of myelopathy in adults over 55 years of age)
  • Thoracic myelopathy
  • Lumbar myelopathy (rare)

Pathophysiology

  • Intramedullary or extramedullary (i.e., originating from within or outside the spinal cord) mass lesions compress the spinal cord and impair its perfusion; mechanic and ischemic axonal injury → intramedullary edema → further narrowing of the medulla

References:[2]

Clinical features

Features depend on the level of compression and the onset may be sudden (e.g., with trauma), step-wise, or slowly progressive (e.g., degenerative diseases)

  • Neck, shoulder, upper limb, or lower limb pain (neck stiffness may be present)
  • Signs and symptoms of lower motor neuron lesions at the level of the lesion; (e.g., weakness and atrophy in the arms and/or hands in lesions of the thoracic spine)
  • Signs and symptoms of an upper motor neuron lesion below the level of the lesion; (e.g., abnormal spastic gait is often an early sign; hyperreflexia or a positive Babinski's sign may be present)
    • Hoffmann's sign: tapping or flicking of the terminal phalanx of the middle or ring finger → flexion of the terminal phalanges of the thumb and index finger
    • Finger escape sign: extension and adduction of fingers → the small finger spontaneously abducts (due to weak intrinsic muscles)
  • Impaired sensation; (e.g., numbness; , impaired proprioception, ataxia)
  • Impaired bladder and bowel control

Damage to the spinal cord and the nerve roots (radiculopathy) often occur simultaneously!

Pain is not commonly an early symptom. Therefore patients may not be diagnosed until myelopathy becomes severe!

References:[3][1]

Diagnostics

  • MRI of the spine: : determines the site of narrowing of the medulla and the underlying pathology
  • Myelography: (possibly with CT): when MRI is contraindicated (e.g., in patients with metal implants)
  • Consider electromyography, nerve conduction studies, and somatosensory evoked potentials of the median and tibial nerve (evaluates nerve functions for providing sensation and motor control to arms and legs)
  • Postvoid residual ultrasound: in case of bladder dysfunction

References:[4][2]

Differential diagnoses

References:[4][5]

The differential diagnoses listed here are not exhaustive.

Treatment

  • Conservative treatment: (i.e., analgesia; , corticosteroid; therapy , bracing; , physiotherapy; ): indicated perioperatively; , for severe cases (e.g., degenerative cervical myelopathy ), and mild cases
  • Decompression surgery: : typically indicated in acute or advanced cases

Acute cervical myelopathy with loss of bladder and bowel control is a neurological emergency that demands immediate surgical decompression!

References:[3][5]