Essay: Acute Posterior Multifocal Placoid Pigment Epitheliopathy (APMPPE)

Introduction:
Gas in 1968 described Acute Posterior Multifocal Placoid Pigment Epitheliopathy (APMPPE) as being a condition that caused acute and rapid loss of central vision due to multiple pale lesions at the level of Retinal pigment epithelium (RPE) in the posterior pole. (1) It is a self-limiting condition which recovers spontaneously over a three weeks period leaving residual pigment epithelial alterations.(2) The typical features in acute phase include cream colored placoid lesions at the level of RPE, early hypofluorescence and late hyperfluorescence of the lesions on Fundus fluorescein angiography (FFA).(2) It is usually followed by a viral flu like prodrome in 1/3 of the patients. Neurological manifestations of APMPPE include Headaches being commonest while others are paraesthesias, vertigo, psychosis and more severe complications, Cerebrospinal fluid pleocytosis stroke and cerebral vasculitis.(3, 4) Association of APMPPE with systemic Vasculitis in the patients with positive perinuclear antineutrophil cytoplasmic antibody has been reported.(5, 6) Other systemic inflammatory diseases suggesting an underlying immune mediated or an inflammatory mechanism include erythema nodosum,(7-9) juvenile rheumatoid arthritis,(10) thyroiditis,(11, 12) nephritis,(5, 6, 13) ulcerative colitis(14) and Adenoviral infections(15) . Many granulomatous diseases have documented associations with APMPPE, including Wegener’s granulomatosis,(16-18) Pulmonary tuberculosis(19) and Sarcoidosis.
The widespread involvement of Retinal Pigment Epithelium (RPE), flat (placoid) nature of the lesions and absence of overlying serous retinal detachment and minimal choroidal involvement lead Gass to conclude RPE was primary focus of inflammation.(1) He attributed the early hypofluorescence of placoid lesions to blockage of choroidal fluorescence by cloudy swelling of RPE. However, later studies using Indocyanine Green Angiography (ICG) suggested a malperfusion of the choroidal vasculature (ICG).(20)
Spectral domain Optical Coherence Tomography (SDOCT) studies have demonstrated dome shaped elevation and disruption of photoreceptor junctions in acute phases of disease.(21) The OCT findings of disease correlate well with the Visual Acuity.
Case reports in literature have described APMPPE with a typical manifestation including serous detachments of retina, papillitis and retinal vasculitis (22-24), making it an intermediate condition between APMPPE and Harada’s disease (25, 26).
Discussion:
Typically APMPPE occurs in younger age with bilateral multiple grey white subretinal lesions(2). In this case unilaterality, papillitis and macular detachment were atypical features which are rarely described in literature.
Reduced visual acuity in affected eye could be attributed to papillitis, serous retinal elevation and the disease itself.
The case appeared to be an intermediate between Harada disease and APMPPE sharing features with both conditions however absence of intraocular inflammation, absence of systemic symptoms, quick resolution and better visual outcome makes Harada disease unlikely(25). Literature has described cases with unilateral involvement, papillitis and retinal detachment(31).(23)
Papillitis in APMPPE is described in very few cases and considered to be due to altered Optic Nerve Head blood supply from choroid.(22, 23, 32). It is evident from this case report that papillitis in APMPPE doesn’t always have neurological associations. This observation has been appears in past literature as well. So it can be assumed/ hypothesized that disc swelling in APMPPE can have an inflammatory/ ischemic origin.
Neurological associations of APMPPE include headaches, paraesthesias, vertigo, psychosis, Cerebrospinal fluid(CSF) pleocytosis and cerebral vasculitis leading to stroke (3, 4, 33). Neurological assessment, CSF analysis and neuroimaging are warranted in settings of neurological symptoms in patients with APMPPE however, neuroimaging and CSF analysis were not considered because of absence of neurological symptoms. Therefore, patient was closely monitored and questioned about the development of such symptoms during each follow up exam; however patient didn’t develop any neurological symptoms in the course of disease.
Many authors have recommended the use of corticosteroids in cases of APMPPE with serous detachment of retina and papillitis (31, 34, 35). Although its effect on disease course and outcome is not well known, the author of this publication believes that systemic steroids should be used in APMPPE with papillitis and retinal detachment.