Acute Posterior Multifocal Placoid Pigment Epitheliopathy (APMPPE)

- Inflammatory choriocapillaritis with secondary RPE involvement; affects healthy individuals, typically <50 years, no sex predilection.

- Etiology poorly understood; may follow viral prodrome (e.g., group A streptococcus, adenovirus type 5, TB, Lyme, mumps) or vaccination (varicella, hepatitis B, swine flu, meningococcus).

- Noninfectious associations: erythema nodosum, granulomatosis with polyangiitis, polyarteritis nodosa, scleritis, sarcoidosis, ulcerative colitis.

- Rare but critical association with cerebral vasculitis; urgent neurologic evaluation (neuroimaging, CSF studies) required if CNS symptoms (e.g., headache) present.

- Presentation: sudden unilateral photopsias and vision loss, with fellow eye involvement days to weeks later; minimal anterior segment inflammation, mild vitritis.

- Fundus: large, flat, yellow-white placoid lesions (1-2 disc areas) in posterior pole; new peripheral lesions in linear/radial array.

- Atypical findings: papillitis, retinal vasculitis, vascular occlusion, neovascularization, exudative retinal detachment (macular edema rare).

- Lesions resolve in 2-6 weeks, leaving depigmentation and pigment clumping.

- FA: early hypofluorescence (blockage) → late hyperfluorescent staining; ICGA: hypocyanescence in acute/inactive phases with more perfusion defects than visible lesions.

- FAF: initially hyperautofluorescent, evolving to hypoautofluorescent; fewer lesions than clinically visible.

- OCT: acute lesions show outer retinal hyperreflectivity, subretinal/intraretinal fluid; resolution may leave photoreceptor loss.

- Differential: syphilis, TB, pneumocystis choroiditis, fungal endophthalmitis, sarcoidosis, choroidal metastasis/lymphoma; ampiginous and serpiginous choroiditis (chronic/progressive unlike APMPPE).

- OCT may mimic Vogt-Koyanagi-Harada (VKH) serous detachments, but clinical features distinguish them.

- Prognosis: good (20/40 or better within 6 months) in most; 20% have residual visual dysfunction.

- Risk factors for poor vision: foveal involvement, older age, unilateral disease, delayed fellow eye involvement, recurrence.

- Treatment: observation typical; corticosteroids considered for extensive macular involvement or CNS vasculitis (urgent systemic steroids to reduce morbidity/mortality).

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Serpiginous Choroiditis

- Rare, chronic, progressive posterior uveitis; equal sex distribution, immune-mediated occlusive vasculitis.

- Associations inconsistent but reported with Crohn disease, sarcoidosis, polyarteritis nodosa; TB can mimic (serpiginous-like choroiditis)—screen all patients.

- Presentation: decreased vision, painless paracentral scotomas, quiet anterior chamber, minimal/no vitritis; bilateral but asymmetric.

- Lesions: active gray-white/creamy yellow RPE-level lesions start peripapillary, progress serpentine/pseudopodial; macular variant in 1/3 of cases.

- Evolution: slow atrophy of retina, RPE, choriocapillaris with fibrosis/hyperpigmentation; new activity at scar edges, possible shallow subretinal fluid.

- CNV develops in up to 25% at scar borders.

- FA: active lesions—early hypofluorescence → late hyperfluorescent staining; scarred lesions—hypofluorescence (choriocapillaris loss/RPE hyperplasia) + transmission hyperfluorescence (RPE atrophy) with sharp margins.

- ICGA: hypocyanescence in all phases, more extensive than FA.

- FAF: inactive scars hypoautofluorescent, active lesions hyperautofluorescent.

- OCT: active—normal/slightly thick retina, hyperreflective outer layers, thickened choroid, possible subretinal fluid; scarred—retinal thinning, outer layer loss, patchy choroidal hyperreflectivity.

- Course: centrifugal extension, progressive scarring, poor visual outcome without treatment.

- Treatment: systemic/local corticosteroids to quiet active lesions (especially fovea-threatening); early IMT (antimetabolite + T-cell inhibitor, cytotoxics like cyclophosphamide/chlorambucil, or TNF inhibitors) improves prognosis.

- Cytotoxics (e.g., chlorambucil) can induce long, drug-free remissions despite severe side effects.

- Adjunctive anti-VEGF/intravitreal steroids for inflammatory CNV.

- Mimics: herpetic/syphilitic choroiditis, TB; TB-associated cases need quadruple therapy ± corticosteroids/IMT.

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Ampiginous Choroiditis (Relentless Placoid Chorioretinitis)

- Uncommon; overlaps features of APMPPE and serpiginous choroiditis; affects ages 10-50, equal sex distribution.

- Presentation: floaters, photopsias, paracentral scotomas, decreased vision, variable anterior segment inflammation/vitritis.

- Lesions: creamy-white placoid, similar to APMPPE/serpiginous; develop at scar borders or de novo; evolve to chorioretinal atrophy.

- Unlike serpiginous: multifocal, separate lesions; peripheral lesions may predate posterior pole; macular lesions not peripapillary.

- Advanced disease mimics serpiginous, including CNV risk.

- FA: active—early blockage → late staining; scarred—transmission/staining like serpiginous.

- Course: prolonged chronic activity (>50 lesions over 2 years possible).

- Treatment: systemic/local corticosteroids, IMT, anti-VEGF based on severity; rule out TB-associated serpiginous-like choroiditis.

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Key Comparisons for Exams

- APMPPE: acute, nonrecurring, good prognosis; serpiginous: chronic, progressive, poor prognosis; ampiginous: chronic with multifocal lesions.

- FA patterns: APMPPE—early hypo → late hyper; serpiginous—similar in active phase, sharp scars in inactive; ampiginous—mixed blockage/transmission.

- OCT: APMPPE—outer retinal hyperreflectivity/fluid; serpiginous—active thick, scarred thin; ampiginous—similar to serpiginous.

- Treatment escalation: APMPPE—observe or steroids; serpiginous/ampiginous—corticosteroids + IMT; BCR—chronic IMT.