CN

Cranial Nerve 6 Palsy

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Cranial Nerve 6 Palsy, CN 6 Palsy, CN VI Paralysis, Sixth Cranial Nerve Paralysis, Abducens Nerve Injury, Lateral Rectus Palsy

  • Causes
  1. Isolated Sixth Nerve Palsy
  2. Brainstem Syndromes
    1. Raymond's Syndrome
      1. Includes CN 6 Palsy
      2. Contralateral Hemiparesis
    2. Millard-Gubler Syndrome
      1. Includes CN 6 Palsy
      2. Ipsilateral CN 7 palsy
      3. Contralateral Hemiparesis
    3. Foville's Syndrome
      1. Includes CN 6 Palsy
      2. Conjugate Gaze Palsy
      3. Ipsilateral Horner Syndrome
      4. Ipsilateral CN 5, CN 7, CN 8 palsies
  3. Subarachnoid space syndrome
    1. Hydrocephalus (Increased Intracranial Pressure)
    2. Hemorrhage, infection, inflammation and cancer within subarachnoid space may also injury CN 6
  4. Petrous apex syndrome
    1. Gradenigo Syndrome
      1. Includes CN 6 Palsy
      2. Ipsilateral Hearing Loss (CN 8)
      3. Ipsilateral facial pain (CN 5)
      4. Ipsilateral facial palsy (CN 7)
    2. Acoustic Neuroma
    3. Cerebellopontine angle meningioma
  5. Cavernous Sinus Syndrome
    1. Nasopharyngeal Cancer
    2. Internal Carotid Artery aneurysm (within Cavernous Sinus)
    3. Carotid-Cavernous fistula
    4. Tolosa-Hunt syndrome (Cavernous Sinus inflammation)
    5. Cavernous Sinus Meningioma
  6. Orbital Syndrome
    1. Includes Proptosis
  7. Miscellaneous
    1. Botulism (bilateral involvement)
    2. Wernicke's Encephalopathy (Conjugate Gaze Palsy)
  • Differential Diagnosis
  1. Internuclear Ophthalmoplegia
  2. Graves Disease (Exophthalmos)
  3. Myasthenia Gravis
  4. Duane's Syndrome
  5. Prior orbital blowout Fracture
  6. Near reflex spasm