A 31-year-old man presents with sudden bilateral blurred vision and paracentral scotomas 2 weeks after a flu-like illness. He has no pain, no redness. He is otherwise healthy. Vision is 6/18 in both eyes.
Examination Findings
Both eyes: multiple flat, cream-coloured placoid lesions at the level of the retinal pigment epithelium in the posterior pole, with mild vitritis. The lesions are bilateral and roughly symmetric. No anterior chamber activity. Foveae are threatened by the lesion distribution.
Investigations
Fluorescein angiography: early hypofluorescence (blocked) with late staining of the placoid lesions — the classic sequence. OCT shows outer-retinal disruption. Systemic workup is limited: APMPPE is usually idiopathic and post-viral, but a neurological history is essential because of the rare but serious association with cerebral vasculitis — any headache with focal neurology needs urgent neuroimaging.
Questions to Think About
- How does APMPPE differ from serpiginous choroiditis, and why does the distinction matter?
- When are systemic steroids indicated in a ‘self-limited’ disease?
- What neurological red flag must every APMPPE patient be warned about?
Diagnosis
Acute posterior multifocal placoid pigment epitheliopathy (APMPPE), bilateral.
Reasoning
The diagnosis is acute posterior multifocal placoid pigment epitheliopathy — the acute, usually self-limited placoid disease of young adults after a viral prodrome. Its critical distinction is from serpiginous choroiditis: APMPPE is acute, bilateral, and self-limited (lesions fade over weeks), while serpiginous is chronic, relentlessly progressive, and peripapillary — mistaking serpiginous for APMPPE and merely observing costs retina. Most APMPPE resolves without treatment, but systemic corticosteroids are indicated when lesions threaten the fovea (as here), when vision is severely affected, or when the disease is unusually aggressive — the ‘self-limited’ label does not forbid treatment of sight-threatening disease. The rare but vital association is cerebral vasculitis: stroke-like symptoms or severe headache with neurology in an APMPPE patient need urgent neuroimaging, and every patient should be warned about this red flag at diagnosis. Syphilis serology is done once to exclude the treatable mimic.
Differential Diagnosis
- Acute posterior multifocal placoid pigment epitheliopathy — fits: bilateral placoid lesions after a viral prodrome in a young adult.
- Serpiginous choroiditis — the key distinction: serpiginous is chronic, progressive, peripapillary, and older — APMPPE is acute and self-limited.
- MEWDS — considered: also post-viral, but smaller dots, usually unilateral, with blind-spot enlargement.
- VKH disease — ruled out: no prodrome of headache/tinnitus, no exudative detachments.
- Syphilis — excluded serologically as always in placoid disease.
Management
Most cases resolve spontaneously — observe with OCT and field monitoring. Give systemic corticosteroids when the fovea is threatened, vision is severely reduced, or disease is aggressive. Exclude syphilis serologically. Warn every patient about the cerebral vasculitis red flag (new severe headache or focal neurology → urgent neuroimaging). Distinguish carefully from serpiginous choroiditis, which needs sustained immunosuppression, not observation.
Key Learning Points
- APMPPE is acute, bilateral, post-viral placoid disease that usually resolves — but fovea-threatening disease deserves systemic steroids.
- Distinguish from serpiginous choroiditis (chronic, progressive, peripapillary) — the management is opposite.
- Warn every patient about the rare cerebral vasculitis association: new neurology needs urgent imaging.
Red Flags
- New focal neurology or thunderclap headache — cerebral vasculitis association, image urgently
- Peripapillary creeping lesions in an older patient — serpiginous, not APMPPE; treat, don’t watch
- Fovea-threatening lesions left untreated — ‘self-limited’ doesn’t mean ‘untreatable’
- Missing syphilis serology — the placoid mimic that needs penicillin
Educational content only — not medical advice. Clinical decisions must be made by a qualified professional for the individual patient.
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