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Amaurosis fugax

Patient will present as → an 82-year-old man presents to the emergency department complaining of vision loss in his left eye. He states that it suddenly appeared as if a curtain was coming down over his left eye. It resolved after five minutes, and his vision returned to normal. He has a history of coronary artery disease and type 2 diabetes.

Amaurosis fugax (amaurosis meaning darkening, dark, or obscure, fugax meaning fleeting) is a painless temporary loss of vision in one or both eyes

  • Amaurosis fugax is not itself a disease. Instead, it is a sign of other disorders.
  • Vision loss is classically described as a curtain coming down over one eye
  • Other descriptions of this experience include monocular blindness, dimming, fogging, or blurring

Five distinct classes based on their supposed cause: embolic, hemodynamic, ocular, neurologic, and idiopathic

A diagnostic evaluation should begin with the patient's history, followed by a physical exam, with particular importance being paid to the ophthalmic examination with regard to signs of ocular ischemia

  • When investigating amaurosis fugax, an ophthalmologic consult is absolutely warranted if available
  • Laboratory tests should also be ordered to investigate some of the more common systemic causes, including a CBC, ESR, lipid panel, EKG, and blood glucose level
  • If laboratory tests are abnormal, a systemic disease process is likely, and if the ophthalmologic examination is abnormal, an ocular disease is likely

Noninvasive duplex ultrasound studies are recommended to identify carotid artery disease if ophthalmic and laboratory findings are inadequate for explanation

  • Carotid imaging – Carotid duplex ultrasound, magnetic resonance angiography (MRA), or computed tomographic angiography should be ordered in all older patients (>50 years) and in younger patients with vascular risk factors (diabetes, hypertension, hyperlipidemia) who have experienced transient monocular visual loss (TMVL)

If the diagnostic workup reveals a systemic disease process, directed therapies to treat that underlying cause should be initiated

  • If the amaurosis fugax is caused by an atherosclerotic lesion, aspirin is indicated, and carotid endarterectomy is considered based on the location and grade of the stenosis
  • Left untreated, this event carries a high risk of stroke; after carotid endarterectomy, which has a low operative risk, there is a very low postoperative stroke rate

Question 1
A patient describes a history of a curtain being brought down over my right eye and it stayed there for a few minutes. Then, it was lifted back up. In which of the following arteries is the etiology of this complaint located?
A
Anterior cerebral
Hint:
Findings in ACA stroke may include the following: Disinhibition and speech perseveration. Primitive reflexes (eg, grasping, sucking reflexes)
B
Middle cerebral
Hint:
Blockage of the MCA results in deficits in movement and sensation (contralateral hemiplegia and hemianesthesia); difficulty swallowing (dysphagia); impaired speech ability (dysarthria, aphasia); and impaired vision and partial blindness (hemianopia);
C
Posterior cerebral
Hint:
Symptoms of posterior cerebral artery stroke include contralateral homonymous hemianopia (due to occipital infarction), hemisensory loss (due to thalamic infarction) and hemi-body pain (usually burning in nature and due to thalamic infarction)
D
Internal carotid
E
External carotid
Hint:
The internal carotid artery supplies blood to the brain. The external carotid artery supplies blood to the face and neck
Question 1 Explanation: 
Amaurosis fugax (amaurosis meaning darkening, dark, or obscure, fugax meaning fleeting) is a painless temporary loss of vision in one or both eyes. Most episodes of amaurosis fugax are the result of stenosis or atherosclerosis of the ipsilateral carotid artery.
Question 2
A 55-year-old woman with a history of hypercholesterolemia reports experiencing several episodes of sudden, brief vision loss in her left eye. Each episode lasted only a few minutes. During the examination, her vision is normal. What is the most appropriate next step in the evaluation of this patient?
A
Carotid Doppler ultrasound
B
Fundoscopic examination
Hint:
Important but may be normal in amaurosis fugax.
C
24-hour Holter monitor
Hint:
Useful if a cardiac source of emboli is suspected.
D
MRI of the brain
Hint:
Indicated if there are concerns for central nervous system pathology.
E
Fluorescein angiography
Hint:
Used for retinal vessel evaluation but not typically first-line in amaurosis fugax.
Question 2 Explanation: 
Carotid Doppler ultrasound is an appropriate next step in evaluating a patient with symptoms suggestive of amaurosis fugax. It helps assess for carotid artery stenosis or plaque, which can embolize to the retinal circulation and cause transient vision loss.
Question 3
A 70-year-old male with a history of amaurosis fugax and newly diagnosed significant carotid artery stenosis is asymptomatic at the time of evaluation. What is the most appropriate management for this patient to prevent future episodes?
A
Immediate carotid endarterectomy
Hint:
Considered in cases with severe carotid stenosis and recurrent symptoms.
B
Antiplatelet therapy
C
Intravitreal injection of anti-VEGF agents
Hint:
Not indicated in amaurosis fugax.
D
Systemic corticosteroids
Hint:
Not effective in preventing amaurosis fugax.
E
Lifestyle modifications only
Hint:
Important but should be combined with medical therapy in the presence of significant carotid stenosis.
Question 3 Explanation: 
Antiplatelet therapy, such as aspirin, is the most appropriate management for a patient with amaurosis fugax, especially with significant carotid artery stenosis. This treatment helps reduce the risk of future thromboembolic events.
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References: Merck Manual · UpToDate

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