Acute Multifocal Placoid Pigment Epitheliopathy Workup

• APMPPE is diagnosed from its typical clinical appearance and disease course. No test is pathognomonic or diagnostic for this disease.
• The following tests may be ordered to help rule out other diseases that may have somewhat similar findings:

  • Antinuclear antibody (ANA)
  • Antineutrophil cytoplasmic antibodies (ANCA)
  • Rheumatoid factor
  • Angiotensin-converting enzyme (ACE)
  • Rapid plasma reagin (RPR)
  • Purified protein derivative (PPD) skin test
  • Anergy panel
  • Chest x-ray
  • Complete blood count (CBC)
  • Sedimentation rate
  • Lyme disease titers
  • Cytomegalovirus (CMV) antibodies
  • Anticardiolipin antibodies

• A CT scan or MRI is indicated in those patients with severe headache or CNS symptoms.
• A cerebral arteriogram may be indicated when cerebral vasculitis is suspected.

• Studies that may assist in the diagnosis of APMPPE include the following:

  • Lumbar puncture: Lymphocytic pleocytosis and elevated protein frequently present in spinal fluid if headache is present.
  • Urinalysis: Transient proteinuria, casts, and lymphocytes may indicate a subclinical microvascular nephropathy.
• Fluorescein angiography

  • Early lesions: Characteristic findings of early hypofluorescence of the lesions are followed by later hyperfluorescence, as shown below, with or without central staining. Fluorescein angiography showing peripheral hypofluorescence and central leakage of the lesion inferior temporal to the macula.
  • Older lesions: Such lesions may show window defects in RPE.Fluorescein angiogram of the patient above in late phase showing late staining of placoid areas. Fluorescein angiography of same patient in late phase showing areas of late staining.
• Indocyanine green (ICG) angiography

  • Early lesions: Numerous round hypofluorescent choroidal defects frequently outnumber those seen on fluorescein angiography. Larger choroidal vessels can be visualized in the hypofluorescent areas, suggesting nonperfusion of choroidal lobules as the source of the typical APMPPE lesions.
  • Older lesions: Partial or complete resolution of the hypofluorescent choroidal areas occurs, and the choroidal findings observed with ICG angiography disappear or resolve earlier than fluorescein angiographic findings. In resolution, the lesions observed with ICG angiography may remain identical to those seen ophthalmoscopically and to the fluorescein angiographic changes.
• Fundus autofluorescence^[5]

  • Fundus autofluorescence (FAF) has been used for the evaluation of the retinal pigment epithelium (RPE) in degenerative, inflammatory, and neoplastic disease conditions. The FAF signal is derived primarily from lipofuscin accumulation within the RPE and may be indicative of altered structure and function.
  • FAF imaging of areas of placoid lesions shows hypoautofluorescence. Once the disease activity subsides, the same areas show hyperautofluorescence.
• Electroencephalography may show diffuse slowing of wave patterns.
• Electroretinogram (ERG) findings may be minimally subnormal.
• Electro-oculogram (EOG) findings may have substantial reduction of light-to-dark ratio studies, which show diffuse functional abnormality of the RPE. Functional recovery may be slow, and, in some instances, it may take up to a year for full recovery.
• Visual fields may show paracentral scotomata early; some visual defects may be permanent.
• Dark adaptation may show delayed in the acute phase, which can return to normal with time after recovery from the acute lesions.
• Optical coherence tomography^[6]

  • In the acute phases, optical coherence tomography (OCT) reveals a mild hyperreflective area above the RPE and, in the later phases, a nodular hyperreflective lesion on the plane of the RPE.
  • These hyperreflective lesions may indicate inflammatory tissue and inflammatory cells or the presence of ischemic edema in the outer retinal layers.
  • Ultra-high resolution OCT of the macula demonstrates early photoreceptor disruption, likely representing early degenerative changes of the photoreceptors. Healed cases continue to demonstrate areas of severe photoreceptor atrophy. Loss of the RPE is also evident during healing and after disease resolution.
• The Stiles-Crawford effect shows early profound disorientation of the photoreceptors.

No histopathology of ocular tissue has been published. Cerebral pathology of a patient with cerebral vasculitis showed granulomatous changes in the vessel wall with giant cells.