History of present illness
A 48-year-old Asian American woman presented to the emergency department reporting 8 hours of painless loss of vision in her right eye. She denied other associated ocular or neurological symptoms. Her past medical history was notable for well-controlled hypertension and for being a former smoker.
Ocular examination findings
Visual acuity with correction was hand motions in the right eye and 20/25–2 in the left eye. Intraocular pressures were normal. The external and anterior segment examination was unremarkable. Dilated fundus examination revealed a “cherry-red spot” in the macula and diffuse retinal edema and whitening in the right eye with an area of preserved retina temporal to the disc. Dilated fundus examination of the left eye showed vascular attenuation but was otherwise normal.
Imaging
Spectral-domain optical coherence tomography (OCT) of the right eye showed an exaggerated foveal contour with diffuse inner retinal edema, marked inner retinal hyperreflectivity, and sparing of the area just temporal to the disc ( Fig. 47.1 ). Fluorescein angiography demonstrated delayed filling and transit times with no evidence of neovascularization.
Questions to ask
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Does the patient present with other neurological symptoms of stroke?
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No. However, given the presenting symptoms and examination findings, appropriate workup was performed and included magnetic resonance angiography, computed tomography angiography, and catheter cerebral angiography.
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Results of imaging studies showed extensive stenosis of the cerebrovascular network with near complete occlusion of the right internal carotid artery with collateral vessel formation. This led to a new diagnosis of Moyamoya disease ( Fig. 47.2 ). The patient subsequently underwent extracranial-intracranial bypass surgery.
Fig. 47.2
Magnetic resonance angiogram of the brain and catheter cerebral angiogram of the head and neck. (A) Magnetic resonance angiogram of the brain shows complete occlusion of the right internal carotid artery (ICA, red arrow ) and middle cerebral artery (MCA) along with mild segmental stenosis of the distal left supraclinoid ICA and proximal left MCA. Severe Moyamoya disease was present on the right and mild disease on the left ( green arrow indicates patent left proximal ICA). (B) Catheter cerebral angiogram of the neck demonstrates complete occlusion of right ICA (right panel, red arrow ) compared with the nonoccluded left ICA (left panel, green arrow ). (C) Catheter cerebral angiogram of the head after left ICA injection shows formation of abnormal right-sided collateral arterial supply (red dotted arrow).
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Does the patient have risk factors for embolic conditions, vasculitis, or a hematological/hypercoagulable state?
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Important vascular risk factors to consider for patients include advancing age, male gender, smoking history, arteriosclerosis, hypertension, diabetes mellitus, and hyperlipidemia.
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Additional diagnostic testing is often warranted and may be tailored to the specific patient.
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Other imaging modalities to consider include transthoracic echocardiography, transesophageal echocardiography, carotid Doppler studies, cerebral angiography, computed tomography of the head, and cerebral magnetic resonance imaging.
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Laboratory tests to consider in younger patients (<50 years) include complete blood cell count, serum chemistries, hemoglobin electrophoresis, prothrombin time, partial thromboplastin time, erythrocyte sedimentation rate, protein C, protein S, antithrombin 3 levels, factor V Leiden, presence of lupus anticoagulant, anticardiolipin antibodies, antinuclear antibodies, antineutrophil cytoplasmic antibodies, angiotensin-converting enzyme, syphilis serology, and serum lipids.
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Does the patient have a history of migraines?
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Migraines in young people may be associated with retinal vascular occlusions. Proposed mechanisms include increased platelet adhesion, vasoconstriction, and activation of the clotting system.
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Does the patient have a history of trauma?
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Trauma may give rise to occlusion of the retinal arterial system.
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Does the patient have risk factors for giant cell arteritis?
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In the appropriate clinical scenario, patients over 50 years of age presenting with acute central retinal artery occlusion (CRAO) should be evaluated for giant cell arteritis including necessary clinical screening questions and laboratory workup. A temporal artery biopsy may also be performed when indicated.
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Assessment
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This is a 48-year-old woman with a history of well-controlled hypertension who presented with a CRAO. Extensive workup revealed a diagnosis of Moyamoya disease. Examination and imaging findings were consistent with CRAO with a cherry-red spot in the macula and retinal whitening. The OCT demonstrated inner retinal edema on initial presentation and subsequent retinal thinning on follow-up. The patient underwent craniotomy for external carotid to intracranial anastomosis.
Diagnostic considerations
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Cardiac valvular disease
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Hereditary and acquired hypercoagulable conditions
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Trauma
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Moyamoya disease
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Vasculitic disorders to consider include giant cell arteritis, Susac syndrome (in cases of multiple branch artery occlusions), systemic lupus erythematosus, polyarteritis nodosa, and granulomatosis with polyangiitis (Wegener granulomatosis)
Differential diagnosis
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CRAO
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Tay-Sachs disease
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Niemann-Pick disease
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Commotio retinae
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Toxicities: methanol, quinine, carbon monoxide
Working diagnosis
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CRAO in setting of previously undiagnosed Moyamoya disease
Multimodal testing and results
Management
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Immediate stroke evaluation and workup are necessary.
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There is no consensus for treatment for CRAO, though some proposed interventions include:
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Ocular massage to dislodge embolus
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Carbogen inhalation
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Paracentesis and/or topical therapy to lower intraocular pressure
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Intravenous carbonic anhydrase inhibitors, such as mannitol or acetazolamide
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Intraarterial thrombolytic therapy
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Nd:YAG laser embolectomy
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Visual prognosis is poor in the setting of CRAO, except in the presence of a patent cilioretinal artery, where central vision is often spared.
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In the setting of Moyamoya disease, patients require advanced neuroimaging and neurosurgical evaluation.
Follow-up care
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At 2-month follow-up visit, examination and OCT demonstrated retinal atrophy and thinning ( Fig. 47.1 D). Vision remained poor at count fingers (CF).
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If patients demonstrate signs of neovascularization, treatment with antivascular endothelial growth factor injections or panretinal photocoagulation should be initiated to prevent further vision loss and complications associated with uncontrolled proliferative disease.
Algorithm 47.1 : Cherry-red spot algorithm
