Nuclear and supranuclear lesions

From greek.doctor
  • Nuclear lesion (bulbar palsy)
    • = bilateral lesion of the motor nucleus of a cranial nerve, its axon, or its NMJ
    • Pathophysiology
      • Cranial nerves IX, X, XI, and XII are affected
      • Equals a “lower motor neuron” lesion, with typical peripheral motor lesion symptoms like atrophy and flaccidity
    • Clinical features
      • Normal facial expressions (because VII is unaffected)
      • Nasal speech
      • Dysphagia of fluids
      • Atrophic and fasciculating tongue
      • Absent gag reflex
  • Supranuclear lesion (pseudobulbar palsy)
    • = bilateral lesion of the corticobulbar tracts
    • Pathophysiology
      • Cranial nerves V, VII, IX, X, XI, XII are affected
      • Equals an “upper motor neuron” lesion, with typical central motor lesion symptoms like spasticity and hyperreflexia
    • Clinical features
      • Stiff, spastic facial muscles -> no facial expressions
      • Spastic dysarthria (Donald Duck voice)
      • Dysphagia
      • Spastic tongue
      • Pseudobulbar affect/emotional incontinence
        • Uncontrollable laughing or crying
        • Think Joaquin Phoenix in the Joker
      • CN V palsy -> exaggerated jaw jerk reflex
      • Brisk gag reflex