Transient, bilateral blurred vision, sometimes with flashing lights. Ataxia, vertigo, dysarthria or dysphagia, perioral numbness, and hemiparesis or hemisensory loss may occur. History of drop attacks (the patient suddenly falls to the ground without warning or loss of consciousness). Symptoms may be induced by position changes or neck hyperextension. Recurrent attacks are common.

Often presents with a normal ocular examination, but may have a hemianopsia, ocular motility deficits, or nystagmus.

Differential Diagnosis of Transient Visual Loss

See Differential Diagnosis in 10.22, Transient Visual Loss/Amaurosis Fugax.

Decreased blood flow in the posterior circulation serving the brain stem and bilateral occipital lobes, often related to atherosclerosis.

1. History: Associated symptoms of vertebrobasilar insufficiency? History of carsickness or migraine? Symptoms of GCA? Smoker?

2. Dilated fundus examination.

3. Blood pressure in each arm to rule out subclavian steal syndrome.

4. Cardiac auscultation to rule out arrhythmia.

5. CBC to rule out anemia and polycythemia, with immediate ESR, CRP, and platelet count if GCA is considered.

6. Electrocardiography, echocardiography, and cardiac monitoring to rule out dysrhythmia.

7. Consider noninvasive carotid flow studies.

8. MRA, CTA, or transcranial/vertebral artery Doppler US to evaluate posterior cerebral blood flow.

1. Coordinated care with internal medicine or neurology with initiation of antiplatelet and/or anticoagulation therapy.

2. Consult internist for hypertension, diabetes, and dyslipidemia control if present.

3. Lifestyle modification (e.g., smoking cessation).

4. Correct any underlying problem revealed by the workup.

If outpatient, 1 week to check test results. Thereafter follow-up time is dictated by identified underlying causative condition(s).