What are the entities in the spectrum of white dot syndromes?

White Dot Syndromes: Disease Entities in the Spectrum

White dot syndromes comprise a heterogeneous group of inflammatory chorioretinopathies affecting the outer retina, retinal pigment epithelium (RPE), choriocapillaris, and choroid, characterized by multiple yellow-white lesions with overlapping clinical features but distinct entities. 1

Core Entities in the Spectrum

The following represent distinct disease entities within the white dot syndrome spectrum, each with unique clinical characteristics:

Multiple Evanescent White Dot Syndrome (MEWDS)

• Presents with minimal inflammation and symmetrically distributed lesions with the least permanent chorioretinal scarring 2
• Visual field defects typically improve in most patients, distinguishing it from more severe entities 2
• Characterized by acute onset with generally favorable prognosis 1

Acute Posterior Multifocal Placoid Pigment Epitheliopathy (APMPPE)

• Presents with rapid onset and progressive marked vision loss, often with slow recovery 3
• Frequently associated with viral prodrome suggesting possible infectious etiology 1
• Represents one of the more common white dot syndromes in pediatric populations 4

Multifocal Choroiditis and Panuveitis (MCP)

• Characterized by multiple yellow-white or gray focal lesions at the RPE and choroid level, accompanied by inflammation in all uveal compartments 5
• Visual loss and field defects result directly from visible lesions or recurrent inflammation around old lesions 2
• Clustering of lesions around the optic nerve and nasal periphery correlates with visual field loss 2
• Complications include glaucoma, cataract, and macular edema requiring aggressive management 6
• Most patients do not show improvement in visual field defects on extended follow-up 2

Punctate Inner Choroidopathy (PIC)

• Presents with enlarged blind spots and field defects explained by fundus lesions 2
• Visual field defects improve in most patients, similar to MEWDS 2
• Patients typically do not have recurrent lesions on extended follow-up 2

Diffuse Subretinal Fibrosis Syndrome

• Represents a severe subset characterized by posterior pole lesions, severe scarring, and significant visual loss 2
• Most patients do not show improvement in visual field defects 2
• Associated with the worst visual prognosis within the spectrum 2

Acute Zonal Occult Outer Retinopathy (AZOOR)

• Included as a distinct entity within the white dot syndrome spectrum 1, 7
• Characterized by outer retinal dysfunction with minimal visible fundus changes 7

Serpiginous Choroiditis/Choroidopathy

• Distinct entity with characteristic geographic spreading pattern 1, 4
• Progressive inflammatory disorder affecting the RPE and choriocapillaris 7

Birdshot Chorioretinopathy

• Recognized as a separate entity within the spectrum 1, 7
• Associated with HLA-A29 in most cases, suggesting autoimmune etiology 1

Acute Retinal Pigment Epitheliopathy

• Included as a distinct entity affecting primarily the RPE 1
• Generally self-limited with good visual prognosis 1

Critical Diagnostic Distinctions

Although enlarged blind spots are a feature of all disorders, clinical, angiographic, and electroretinographic evidence confirms these are different entities rather than a single disease spectrum 2. The key distinguishing features include:

• Pattern of lesion distribution: MEWDS shows symmetric distribution, while MCP demonstrates peripapillary and nasal clustering 2
• Degree of inflammation: MEWDS has minimal inflammation versus MCP's panuveitis 2, 6
• Visual prognosis: MEWDS and PIC show improvement, while MCP and diffuse subretinal fibrosis syndrome typically do not 2
• Recurrence patterns: MCP shows recurrent inflammation around old lesions, while PIC and MEWDS do not 2

Diagnostic Workup Requirements

Multimodal imaging including OCT, fluorescein angiography (FA), indocyanine green angiography (ICGA), and OCT-angiography is essential to establish diagnosis and differentiate between entities 5. Specific findings include:

• OCT identifies subretinal fluid, outer retinal disruption, cystoid macular edema, and subretinal fibrosis 5
• FA demonstrates focal leakage points and choroidal neovascularization 5
• ICGA shows hypofluorescent changes on late-phase imaging characteristic of white dot syndromes 5, 7
• OCT-angiography detects neovascular networks when present 5, 7

The relative frequency of white dot syndromes in pediatric uveitis patients is estimated between 1-5%, with different age predilections for different entities 4.