II. Symptoms: Red Flags for CNS Cause

  1. Sudden change in vision (or worsening over hours to days)
  2. Unilateral Vision Loss with Eye Pain or pressure
  3. Vision Loss with Vomiting, severe Headache or Altered Level of Consciousness
  4. Distorted or blurry vision without ocular cause (e.g. Cornea abrasion, anterior chamber, lens, Retina)
  5. Acute Retinal Artery Occlusion
    1. Evaluate as stroke variant with emergent carotid imaging including aortic arch (CT Head, CT Angiogram head and neck)
    2. Central Retinal Artery Occlusion (CRAO)
    3. Branch Retinal Artery Occlusion (BRAO)
    4. Ophthalmic Artery Occlusion
  6. Amaurosis Fugax (Transient Monocular Blindness)
    1. See Acute Vision Loss
    2. Central Retinal Artery Occlusion
    3. Temporal Arteritis
  7. Binocular Diplopia (acute onset)
    1. Diplopia only with both eyes open
  8. Internuclear Ophthalmoplegia (Conjugate Gaze Palsy)
    1. Medial Longitudinal Fasciculus lesion results in discordance between CN 3 and CN 6
  9. Afferent Pupillary Defect
    1. Intact Consensual Light Reflex (but not to direct light)
    2. Ischemic Optic Neuropathy
    3. Multiple Sclerosis
  10. Acute Cranial Nerve Palsy (CN 3, 4, 6)
    1. Oculomotor Nerve Palsy (CN 3 Palsy)
      1. Pupil-involving acute CN 3 Palsy may be expanding Cerebral Aneurysm (esp. Posterior Communicating Artery)
    2. Abducens Nerve Palsy (Cranial Nerve 6 Palsy)
      1. Long, thin nerve subject to injury
      2. Bilateral palsy may occur in Increased Intracranial Pressure, Wernicke's Encephalopathy, Botulism
    3. Trochlear Nerve Palsy (CN 4 Palsy)
      1. Long, thin nerve also subject to injury
  11. Horner's Syndrome
    1. Miosis, Ptosis and Anhidrosis

III. References

  1. Marcolini in Herbert (2020) EM:Rap 20(8): 8-9
  2. Marcolini in Herbert (2021) EM:Rap 21(1): 6

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