PANCE Blueprint EENT (7%)

Patient with retinal artery occlusion will present as → a 74-year-old man with sudden vision loss in his right eye. He has a medical history of hypertension, coronary artery disease, and new-onset atrial fibrillation. On physical exam, a carotid bruit is auscultated. His visual acuity is light perception. Confrontational visual fields reveal a dense scotoma, and a penlight examination shows an afferent pupillary defect. Dilated funduscopic examination shows retinal whitening with a cherry-red spot in the fovea.

Patient with retinal vein occlusion will present as → a 65-year-old woman who presents to the ED with the sudden onset of painless vision loss in her left eye. Her past medical history includes hypertension and hyperlipidemia. The patient’s temperature is 98°F (36.7°C), blood pressure is 145/86 mmHg, pulse is 62/min, and respirations are 12/min with an oxygen saturation of 98% O2 on room air. An ophthalmology consult is called, and the fundoscopic examination reveals a swollen optic disc with extensive retinal hemorrhages.

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A retinal artery or vein occlusion, also known as an eye stroke, is a blockage of one of the blood vessels feeding the retina, which is the light-sensitive nerve tissue lining the back of the eye. Both cause a monocular painless vision loss.

• A blockage results in a lack of oxygen getting to the nerve cells in the retina, which may result in drastic vision loss
• Blockages happen in the arteries supplying blood to the retina and veins that take blood away from the eye. These blockages involve most of the retina (central) or a portion of the retina (branch)
  • Central retinal artery occlusion (CRAO): This blockage of the main artery supplying blood (and oxygen) to the eye has the highest potential to cause the most damage to the eye, resulting in severe vision loss.
  • Branch retinal artery occlusion (BRAO): This is a blockage of one artery in the retina more in the retinal periphery. It causes severe loss of vision in that location but doesn’t typically affect the central vision.
  • Central retinal vein occlusion (CRVO): This is a blockage of the main vein that drains blood from the retina and causes severe loss of vision as fresh oxygenated blood cannot get into the eye. This is more common than a CRAO and is associated with high blood pressure and diabetes
  • Branch retinal vein occlusion (BRVO): Blockages of the branches of the retinal vein are called branch retinal vein occlusions. These blockages cause blood and fluid to spill into the retina and cause swelling that impacts your ability to see.

Central retinal artery occlusion is characterized by sudden, painless acute visual loss usually attributed to ischemia or thrombus to the major retinal arterial blood supply

• Caused by an embolism resulting from atrial fibrillation, cardiac vegetation, or a patent foramen ovale, but might be also due to thrombosis of the retinal artery, usually as a result of atherosclerosis
  • Commonly results from ruptured plaque from the same-sided (ipsilateral) carotid artery
• Typically, the patient presents with sudden, painless onset of markedly decreased unilateral loss of vision (amaurosis fugax)
• Physical examination findings include a significant decrease in visual acuity, relative afferent pupillary defect (ie, Marcus Gunn pupil)
• Fundoscopy reveals a cloudy, pale retina with attenuated vessels and a cherry-red spot in the fovea
  • The cherry-red spot is seen because the macula receives its blood supply from the choroid, which remains unaffected, while the surrounding retina is pale and ischemic due to the retinal artery occlusion

Retinal vein occlusion

• This manifests as a sudden acute monocular vision loss
• Can be further divided into non-ischemic and ischemic subtypes
• Compression of the central retinal vein or one of its branches due to a thrombus, a narrow vein, or from an atherosclerotic artery crossing it
• For diagnosis, look for a history of cardiovascular risk factors, such as diabetes mellitus and hypertension, or hypercoagulable states like polycythemia vera
• A fundoscopic examination may reveal optic disc swelling, retinal hemorrhages, and dilated veins that give a characteristic “blood and thunder appearance”

Fundoscopy of retinal artery occlusion ⇒ cherry-red spot on the macula and pale retina

Fundoscopy of retinal vein occlusion ⇒ optic disc swelling, retinal hemorrhages, and dilated veins that give a characteristic “blood and thunder appearance”

Central retinal artery occlusion is an ophthalmologic 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
• Treatment may include hyperbaric oxygen therapy, which involves the inhalation of 100% oxygen at a pressure that’s higher than the atmospheric pressure

Retinal vein occlusion is treated with laser photocoagulation and steroid or anti-VEGF injections