Updated: 12/31/2019

Retinal Artery Occlusion / Amaurosis Fugax

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Snapshot
  • A 76-year-old man presents to the emergency department with sudden vision loss in his right eye. He described the onset as if a curtain came down over his eye. He has a medical history of hypertension and coronary artery disease. On physical exam a carotid bruit is heard. A funduscopy exam demonstrates whitening of the retina. 
Introduction
  • Overview
    • occlusion of the retinal artery, leading to occlusion/infarction of the retina
      • can result in permanent or transient vision loss (amaurosis fugax
      • 2 types
        • central retinal artery occlusion
          • occlusion of the central retinal artery leading to monocular vision loss
        • branch retinal artery occlusion
          • occlusion of the arteriolar branch of the central retinal artery leading to segmental monocular vision loss
  • Epidemiology
    • incidence
      • more common in the elderly
    • risk factors
      • carotid artery atherosclerosis
        • carotid Doppler for further evaluation 
      • atrial fibrillation
      • arterial hypertension
      • diabetes mellitus
      • hypercholesterolemia
      • carotid artery dissection
      • fibromuscular dysplasia
  • Pathophysiology
    • cholesterol embolism is the most common cause  
      • leads to occlusion of the retinal artery
  • Associated condition
    • acute ischemic stroke
    • migraines
    • giant cell arteritis
  • Prognosis
    • increased risk for cardiovascular and cerebrovascular events
Presentation
  • Symptoms
    • acute and painless monocular vision loss 
  • Physical exam
    • retinal whitening (suggestive of ischemia)
    • "cherry-red spot" 
      • cherry-red macula surrounded by opacified retina
    • carotid bruit if caused by carotid atherosclerotic disease 
Studies
  • Fundus fluorescein angiography
    • indication
      • when funduscopic findings for retinal artery occlusion are not present/unclear
  • Serum studies
    • erythocyte sedimentation rate and C-reactive protein
      • > 50 years of age with a central retinal artery occlusion
Differential
  • Retinal detachment
    • differentiating factor
      • may appreciate retinal tear or see the detachment
  • Migrain with aura
    • differentiating factor
      • headache is typically present
Treatment 
  • Currently no known effective therapy
  • Medical
    • ocular massage
      • indication
        • conservative management
          • may theoretically lead to the emboli to move more distally in the artery to reduce retinal ischemia
    • carbogen inhalation or hyperbaric oxygen 
      • indication
        • thought to cause vasodilation in an attempt to pass the clot into a distal segment of the occluded vessel 
  • Surgical 
    • anterior chamber paracentesis
      • indication
        • to decrease intraocular pressure in order to move the emboli more distally in the artery to reduce retinal ishcemia
Complications
  • Blindness
 

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Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Volume  
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Urine  
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2
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(M2.OP.16.4694) A 65-year-old man, with a history of transient ischemic attack, presents to the emergency department complaining of sudden loss of vision in his right eye. Physical exam reveals a dilated and sluggish right pupil. On fundoscopy the right retina is pale, the fovea is dark red (Figure A). What is the proper treatment for this patient? Review Topic | Tested Concept

QID: 107686
FIGURES:
1

IV acetazolamide, pilocarpine, laser iridotomy

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2

Laser or cryotherapy to reattach the retina

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3

IV acetazolamide, ocular massage, carbogen therapy

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4

Ranibizumab

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5

Observation, elevate head of the bed at nighttime

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(M2.OP.15.75) A 67-year-old woman presents to the emergency department complaining of right eye blindness. She states she first noticed the vision loss when she woke up this morning. She denies any pain or other associated symptoms. Review of systems is notable for passive suicidal ideation as the patient's husband died in the ICU last night. Her temperature is 98.3°F (36.8°C), blood pressure is 174/104 mmHg, pulse is 80/min, respirations are 12/min, and oxygen saturation is 98% on room air. Physical exam is notable for the patient being unable to see out of her right eye with normal vision in her left eye. Her cranial nerves are otherwise intact and she has normal strength and sensation in her upper and lower extremities. A fundoscopic examination is performed and the results are demonstrated in Figure A. Which of the following is the most likely etiology of this patient's symptoms? Review Topic | Tested Concept

QID: 106755
FIGURES:
1

Arterial embolization

16%

(10/62)

2

Detachment of the retina

2%

(1/62)

3

Emotional stress

5%

(3/62)

4

Increased intraocular pressure

58%

(36/62)

5

Ischemia of the brain

15%

(9/62)

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(M2.OP.14.24) A 74-year-old man with a history of type II diabetes and a 40 pack-year smoking history presents to the emergency room complaining of sudden-onset, painless vision loss in his left eye. He describes the feeling as if things went black in his left eye suddenly. His temperature is 98.0°F (36.7°C), blood pressure is 154/94 mmHg, pulse is 100/min, respirations are 17/min, and oxygen saturation is 98% on room air. Neurological exam reveals cranial nerves III-XII as intact. The patient is unable to see out of his left eye but has normal vision in his right eye. The rest of his exam including strength, sensation, and gait are unremarkable. An ECG is performed as seen in Figure A and an ultrasound of the eye is performed as seen in Figure B. Fundoscopy is performed as seen in Figure C. A CT scan of the head is currently pending. Which of the following is the most likely diagnosis? Review Topic | Tested Concept

QID: 104471
FIGURES:
1

Central retinal artery occulsion

30%

(3/10)

2

Central retinal vein occlusion

30%

(3/10)

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Hemorrhagic stroke

0%

(0/10)

4

Ischemic stroke

40%

(4/10)

5

Retinal detachment

0%

(0/10)

L 2 E

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