Amaurosis Fugax 2/5/2019

We presented a case of a 63yo M with 30-pk-yr tobacco use, HTN, HLD, and prior CVD 7 months ago presenting with acute onset vision loss of the left eye, described as “seeing through a black mesh with spots of clear vision.” His symptom lasted for 2 hours before gradually resolving on its own. His cardiovascular and neuro exam were unremarkable, and his fundoscopic exam was normal other some mild AV nicking (a sign found with long standing hypertension). Labs and imaging including CTA did not find any acute etiology. A MR of the orbit was also done without any abnormal findings.

Ultimately pt was diagnosed with transient monocular vision loss (TMVL) most likely secondary to an episode of TIA!


Common things being more common, the most common cause of transient monocular vision loss is ischemia/vascular related!

Ischemic/Vascular Etiology

  • TIA
  • CRVO: Classic painFUL vision loss, flame hemorrhage (blood and thunder descriptor) on fundoscopic exam
    • Acute angle closure glaucoma is the most common factor predisposing to retinal retinal vein occlusion
    • Other risk factors: Sickle cell, HIV, Waldenstrom, sarcoidosis, syphilis
  • CRAO: Classic painLESS vision loss, cherry red spot with retinal pallor is a classic description
  • Carotid artery syndrome (transient retinal hypoperfusion or microemboli)

Neurology Etiology

  • Optic neuritis
  • MS
  • NMO
  • Optic nerve ischemia
  • Increased ICP

Inflammatory Etiology

  • GCA
    • Association with polymyalgia rheumatica
    • Typical patient demographics: Age > 55, F > M (2:1), Scandinavian/Northern European ancestry
    • Other associated sx: Fever, headache, jaw claudication, scalp tenderness
    • ESR and CRP typically elevated but this is NOT always the case!

Other

  • Glaucoma
  • Idiopathic
  • Smart phone use in the dark (I am not kidding), please see this article for more details

Management of TIA

In addition to treating risk factors i.e. HTN, HLD, DM2, a question often came up…

To DAPT or not DAPT?

CHANCE, a multicenter, randomized, placebo-controlled trial published in 2013 (Wang et al.) in the NEJM, revealed that DAPT within 24 hours after a TIA or mild ischemic stroke is beneficial in reducing 90-day stroke risk without an increase in bleeding complications vs aspirin monotherapy. This study was done in China with a patient population with higher incidence of undertreated modifiable risk factors and greater cerebral vascular disease burden, hence its applicability to an American patient population is unclear.

Then the POINT trial came along funded by the NIH, which saw the same benefit in DAPT after TIA/ischemic stroke but with increased bleeding risk compared to aspirin monotherapy.

Bottomline: CHANCE indicates 21 days of DAPT post TIA/ischemic stroke is helpful without increasing bleeding risk, and in POINT, 90 days of DPT is also beneficial but it increases bleeding risk. Per 2018 AHA/ASA guideline:

  • In patients presenting with minor stroke, treatment for 21 days with dual antiplatelet therapy (aspirin and clopidogrel) begun within 24 hours can be beneficial for early secondary stroke prevention for a period of up to 90 days from symptom onset.

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