Central & Branch Retinal Artery Occlusions

Essentials of Diagnosis

• Sudden monocular loss of vision

• No pain or redness

• Widespread or sectoral pale retinal swelling

General Considerations

• In patients aged 50 years or older with central retinal artery occlusion, consider giant cell arteritis

• Carotid and cardiac sources of emboli must be sought so that treatment can be given to reduce the risk of stroke

• In young patients, causes include

  • Migraine

  • Oral contraceptives

  • Systemic vasculitis

  • Congenital or acquired hypercoagulable states (thrombophilia)

• Internal carotid artery dissection should be considered when there is neck pain or a recent history of neck trauma

• In all patients, consider

  • Diabetes mellitus

  • Hyperlipidemia

  • Systemic hypertension

• Giant cell arteritis should be considered in cases of central retinal artery occlusion without visible emboli

Symptoms and Signs

• Central retinal artery occlusion

  • Presents as sudden profound monocular visual loss

  • Visual acuity is usually reduced to counting fingers or worse

  • Visual field may be restricted to an island of vision in the temporal field

• Branch retinal artery occlusion

  • May also present with sudden loss of vision if the fovea is involved, but more commonly sudden loss of a discrete area in visual field in one eye is the presenting complaint

  • Fundus signs of retinal swelling and adjacent cotton-wool spots are limited to the area of retina supplied by the occluded artery

• Identify risk factors for a cardiac source of emboli including arrhythmia, particularly atrial fibrillation, and cardiac valvular disease; and check the blood pressure

• Clinical features of giant cell arteritis include

  • Jaw claudication (which is very specific)

  • Headache

  • Scalp tenderness

  • General malaise

  • Weight loss

  • Polymyalgia rheumatica: shoulder and hip girdle pain

  • Tenderness or thickening of, or absence of pulse in, the superficial temporal arteries

Laboratory Tests

• Test for diabetes (fasting serum glucose, hemoglobin A_1C) and hyperlipidemia (fasting serum cholesterol, HDL cholesterol, LDL cholesterol, triglycerides) in all patients

• Erythrocyte sedimentation rate and C-reactive protein are usually markedly elevated in giant cell arteritis but one or both may be normal

• Consider testing for other types of vasculitis (eg, antinuclear antibody, rheumatoid factor, anticytoplasmic neutrophil antibody)

• In younger patients, consider tests for congenital or acquired hypercoagulable states (thrombophilia)

  • Antiphospholipid antibody syndrome (lupus anticoagulant)

  • Activated protein C resistance/Factor V Leiden

  • Protein C, protein S deficiency

  • Antithrombin deficiency

  • Hyperprothrombinemia (G20210A prothrombin gene mutation)

  • Increased Factor VIII activity

  • Hyperhomocysteinemia

Imaging Studies

• Obtain duplex ultrasonography of the carotid arteries, ECG, and echocardiography (with transesophageal echocardiography, if necessary), to identify carotid and cardiac sources of emboli

• When indicated, obtain CT or MR angiography studies for internal carotid artery dissection

Diagnostic Studies

• Central artery occlusion: Ophthalmoscopy

  • Reveals pale swelling of the retina with a cherry-red spot at the fovea

  • The retinal arteries are attenuated, and "box-car" segmentation of blood may be seen in the retinal veins

  • Occasionally, emboli are seen in the central retinal artery or its branches

• Optical coherence tomography

  • The retinal swelling subsides over a period of 4–6 weeks, leaving a pale optic disk with thinning of the inner retina

• If the patient is seen within a few hours after onset, emergency treatment may influence visual outcomes and includes

  • Laying the patient flat

  • Ocular massage

  • High concentrations of inhaled oxygen

  • Intravenous acetazolamide

  • Anterior chamber paracentesis

• In central retinal artery occlusion not due to giant cell arteritis, early thrombolysis, particularly by local intra-arterial injection but also intravenously, may be beneficial

• Recommended initial empiric treatment for giant cell arteritis

  • Perform a temporal artery biopsy promptly

  • Institute a high-dose corticosteroid regimen immediately (possibly with low-dose aspirin (~81 mg/day orally)

    • Intravenous methylprednisolone 0.5–1 g/day for 1–3 days

    • All patients require subsequent long-term glucocorticoid therapy (eg, oral prednisone 1–1.5 mg/kg/day) and possibly low-dose aspirin (~81 mg/day orally)

    • Whether oral methylprednisolone is similarly effective is unknown

  • Monitor the patient closely to ensure that symptoms resolve and do not recur

• Carotid endarterectomy or angioplasty with stenting should be considered in patients in whom the following are present:

  • Embolic retinal artery occlusion

  • Ipsilateral carotid artery stenosis (70–99%)

  • Possibly, ipsilateral carotid artery stenosis (50–69%)

• Surgical treatment of cardiac valvular disease and patent foramen ovale may be required

Prognosis

• In giant cell arteritis, there is risk of involvement of the other eye without prompt treatment

When to Refer

• Patients with retinal artery occlusions should be referred urgently to an emergency department to evaluate the patient for stroke manifestations and treatment

• Patients with central retinal artery occlusion should be referred emergently to an ophthalmologist

• Patients with branch retinal artery occlusion should be referred urgently to an ophthalmologist

When to Admit

• Patients with visual loss due to giant cell arteritis may require emergency admission for high-dose corticosteroid therapy and close monitoring to ensure that treatment is adequate