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transient monocular blindness (TMB); amaurosis fugax

Etiology: 1) transient ischemic attack (painless) 1) temporal arteritis (elevated ESR) 2) optic nerve disorders a) optic neuritis b) ischemic optic neuropathy c) papilledema - pseudotumor cerebri 3) ocular disorders a) acute glaucoma (expectation of painful vision loss) [ABIM] b) retinal artery branch occlusion c) central retinal vein occlusion d) retinal detachment e) retinal artery vasospasm Clinical manifestations: - may obscure only the upper or lower 1/2 of vision in one eye, the entire visual field in one eye, or may be perceived by the patient as a graying of vision - retinal detachment may appear as a black curtain that progresses across the visual field Special laboratory: - dilated opthalmoscopy - abnormal visual acuity testing or visual field testing - eye pain - history of glaucoma or optic neuritis Radiology: - carotid doppler ultrasound - MRI of brain with diffusion weighted imaging (see TIA) Complications: - predicts blindness in patients with temporal arteritis [4] Management: 1) treat transient ischemic attack (TIA) if likely cause 2) prognosis [2] - epsiode of transient monocular blindness confers lower risk of subsequent stroke than does hemispheric TIA 3) carotid endarterectomy beneficial only for high-risk patients [2]

General

blindness visual impairment

References

  1. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 1021-22
  2. Journal Watch 21(22):180, 2001 Benavente et al, N Engl J Med 345:1084, 2001 Sacco RL, N Engl J Med 345:1113, 2001
  3. Medical Knowledge Self Assessment Program (MKSAP) 16, American College of Physicians, Philadelphia 2012 - Ahmed R, Foroozan R. Transient monocular visual loss. Neurol Clin. 2010 Aug;28(3):619-29 PMID: 20637992
  4. NEJM Knowledge+ Rheumatology