PANCE Blueprint EENT (9%)

Retinal vascular occlusion

Patient will present with → a history of atrial fibrillation and sudden, painless, unilateral, and usually severe monocular vision loss (amaurosis fugax)

Central retinal artery occlusion is characterized by acute visual loss usually attributed to ischemic or thrombus to the major retinal arterial blood supply. Typically, the patient presents with sudden, painless onset of markedly decreased unilateral loss of vision (amaurosis fugax).

  • Physical examination findings include significant decrease in visual acuity, relative afferent pupillary defect (ie, Marcus Gunn pupil), and a pale retina with a red spot that is visible on funduscopic examination.
  • When a patient presents with monocular vision loss you need to be thinking of three things:
    • retinal artery occlusion
    • optic neuritis
    • Temporal (Giant) cell arteritis.
  • Commonly results from ruptured plaque from same-sided (ipsilateral) carotid artery
  • Think atrial fibrillation, endocarditis, valvular heart disease, hypercoagulable states etc.

Fundoscopy of retinal artery occlusion will reveal a cherry red spot on macula and pale retina

Cherry Red Spot Retinal Vascular Occlusion

As expected, this is an optho emergency. Immediate treatment is indicated if occlusion occurred within 24 h of presentation.

  • Reduction of intraocular pressure with ocular hypotensive drugs (eg, topical timolol 0.5%, acetazolamide 500 mg IV or PO)
  • Intermittent digital massage over the closed eyelid or anterior chamber paracentesis may dislodge an embolus and allow it to enter a smaller branch of the artery, thus reducing the area of retinal ischemia.

If patients present within the first few hours of occlusion, some centers catheterize the carotid/ophthalmic artery and selectively inject thrombolytic drugs.

Question 1
In a patient with amaurosis fugax what is the most appropriate initial diagnostic study?
A
Ophthalmoscopy
Hint:
Ophthalmoscopy provides visualization of retina but does not help elucidate the source of the plaque.
B
Schiotz tonometry
Hint:
Schiotz tonometry is used to measure intraocular pressure.
C
MR angiography
Hint:
MR angiography is a useful test to identify retinal vascular anatomy but is not the first choice in the search for causes of amaurosis fugax.
D
Carotid ultrasound
Question 1 Explanation: 
The most common cause of amaurosis fugax is an atherosclerotic plaque in the carotid artery which can be identified with ultrasound.
Question 2
45-year-old woman presents to the ED with acute painless loss of vision, photophobia associated with a smaller unilateral pupil on the involved side. Which of the following is the most likely diagnosis?
A
central retinal vein occlusion (CRVO)
Hint:
Central retinal vein occlusion (CRVO) is characterized by painless, unilateral vision loss of varying severity, slower onset of decreased vision than with arterial occlusion, retinal hemorrhages, cotton wool spots, and macular edema.
B
iritis/uveitis
Hint:
See E for explanation
C
retrobulbar hemorrhage or hematoma
Hint:
Retrobulbar hemorrhage is associated with decreased ocular range of motion, decreased vision, ptosis of the lid, and increased pressure in the globe raising intraocular pressure. The high pressure decreases retinal artery perfusion, which results in retinal ischemia. The patient presents with decreased visual acuity, proptosis, and a dilated nonreactive pupil.
D
hyphema
Hint:
A hyphema is caused by bleeding from the vasculature of the iris usually precipitated by trauma. Blood is often visualized in the anterior chamber and can be seen via slit lamp evaluation. Symptoms usually consist of pain, photophobia, and decreased vision. Intraocular pressures may increase as well. The major clinical consideration is the potential of reoccurring bleeding.
E
central retinal artery occlusion
Question 2 Explanation: 
Central retinal artery occlusion is characterized by acute visual loss usually attributed to ischemic or thrombus to the major retinal arterial blood supply. Typically, the patient presents with sudden, painless onset of markedly decreased unilateral loss of vision. Physical examination findings include significant decrease in visual acuity, relative afferent pupillary defect (ie, Marcus Gunn pupil), and a pale retina with a red spot that is visible on funduscopic examination. Central retinal vein occlusion (CRVO) is characterized by painless, unilateral vision loss of varying severity, slower onset of decreased vision than with arterial occlusion, retinal hemorrhages, cotton wool spots, and macular edema. Physical examination findings include ciliary flush (ie, circumcorneal perilimbal injection of the episcleritis and scleral vessels) conjunctival injection and cells may be present in the anterior chamber. The pupil on the affected side is often small and irregular. Direct and consensual light reflex will cause pain on the affected side to increase. Retrobulbar hemorrhage is associated with decreased ocular range of motion, decreased vision, ptosis of the lid, and increased pressure in the globe raising intraocular pressure. The high pressure decreases retinal artery perfusion, which results in retinal ischemia. The patient presents with decreased visual acuity, proptosis, and a dilated nonreactive pupil. A hyphema is caused by bleeding from the vasculature of the iris usually precipitated by trauma. Blood is often visualized in the anterior chamber and can be seen via slit lamp evaluation. Symptoms usually consist of pain, photophobia, and decreased vision. Intraocular pressures may increase as well. The major clinical consideration is the potential of reoccurring bleeding.
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