Differential Diagnosis for Sudden Loss of Vision with Headache

Single Most Likely Diagnosis

• Giant Cell Arteritis: This condition is a common cause of sudden vision loss in adults over 50, but can also occur in younger individuals. The accompanying headache is a classic symptom, often described as temporal or occipital. The sudden loss of vision, usually in one eye, is due to ischemia of the optic nerve.

Other Likely Diagnoses

• Optic Neuritis: An inflammatory condition of the optic nerve that can cause sudden vision loss, often accompanied by pain on eye movement. It's more common in younger adults and can be associated with multiple sclerosis.
• Central Retinal Artery Occlusion: A blockage of the central retinal artery, leading to sudden, painless loss of vision in one eye. However, headache might not be a primary symptom but can occur due to associated conditions.
• Migraine: Though typically associated with visual auras, migraines can occasionally cause transient monocular vision loss. The headache is usually severe and can be accompanied by nausea and sensitivity to light.

Do Not Miss Diagnoses

• Pituitary Apoplexy: A medical emergency where a pituitary tumor suddenly hemorrhages or infarcts, leading to acute loss of vision (due to compression of the optic chiasm), severe headache, and potentially life-threatening hormonal imbalances.
• Subarachnoid Hemorrhage: A bleed into the space surrounding the brain, often presenting with a sudden, severe headache (described as "the worst headache of my life") and can be associated with transient visual disturbances or loss due to increased intracranial pressure.
• Cavernous Sinus Thrombosis: A rare but potentially life-threatening condition involving a blood clot in the cavernous sinus, which can cause sudden vision loss, headache, and other neurological symptoms due to the involvement of multiple cranial nerves.

Rare Diagnoses

• Susac Syndrome: A rare condition characterized by microangiopathic changes in the brain, retina, and inner ear, leading to vision loss, hearing loss, and neurological symptoms. The vision loss is typically due to branch retinal artery occlusions.
• Eale Disease: A rare idiopathic condition causing retinal vasculitis and neovascularization, leading to recurrent retinal and vitreal hemorrhages and vision loss. It's more common in young adults and can be associated with headaches due to secondary causes.