Systemic Disease and Ocular Manifestations
This domain tests systemic diseases with ocular manifestations and the urgency of referral. Diabetes, hypertension, thyroid disease, and giant cell arteritis are highest yield.
Core rules
- Diabetic retinopathy: nonproliferative changes include microaneurysms, dot-blot hemorrhages, hard exudates, and cotton-wool spots; proliferative disease shows neovascularization. Macular edema can occur at any stage.
- Hypertensive retinopathy: arteriolar narrowing, AV nicking, flame hemorrhages, cotton-wool spots, and papilledema in malignant hypertension.
- Graves orbitopathy: proptosis, lid retraction, restrictive myopathy, and optic neuropathy; smoking worsens it.
- Giant cell arteritis: older age, headache, jaw claudication, elevated ESR/CRP, and anterior ischemic optic neuropathy; treat immediately with high-dose corticosteroids.
- Other associations: sarcoidosis (granulomas, uveitis), syphilis (uveitis, optic neuropathy), multiple sclerosis (optic neuritis), sickle cell (proliferative retinopathy).
Worked example
A 72-year-old has sudden unilateral vision loss, scalp tenderness, and an ESR of 80 mm/hour. Reasoning: giant cell arteritis is the diagnosis until proven otherwise. High-dose corticosteroids should start immediately to protect the fellow eye; temporal artery biopsy can follow but should not delay treatment.
Traps that cost marks
- Waiting for a biopsy before treating suspected giant cell arteritis.
- Confusing diabetic macular edema with proliferative retinopathy; edema is a separate treatment indication.
- Missing dysthyroid optic neuropathy in a patient with proptosis and decreased acuity.