Description
This bilateral, acute, self-limiting disorder is characterized by grey-white lesions scattered throughout the posterior pole, in association with mild to marked visual loss. It has been classified among the ‘white dot syndromes’, characterized by multiple chorioretinal lesions, visual loss and photopsia, most often in young adults. APMPPE affects men and women equally, usually between 20 and 40 years of age. Although no cause has been identified, there is an association with a recent systemic illness, suggesting ocular involvement in a more generalized inflammatory or immune process. Antecedent upper respiratory tract infections are most common; other reported associations include cerebral vasculitis, mumps and streptococcal infection. It has also been suggested that patients with certain HLA types are predisposed to this condition. Similarly, the pathological process has not been elucidated definitively. One hypothesis is that APMPPE begins with an occlusive choroidal vasculitis, which is followed by a secondary reaction in the overlying retinal pigment epithelium.
Symptoms
Patients report a combination of photopsia, scotomata and blurred vision. The second eye is usually involved within a few days to weeks after the first. Unilateral APMPPE is rare.
Signs
In acute APMPPE, there are multiple, flat, grey-white lesions with indistinct margins in the post-equatorial fundus. The lesions are usually separate, but occasionally confluent. They are generally at a similar stage of evolution (this helps to distinguish APMPPE from serpiginous chorioretinitis, in which acute lesions often appear adjacent to atrophic, scarred areas). Mild
vitreous inflammation is common, and vascular sheathing is seen occasionally. Acuity ranges from normal to 20/200 (or worse when lesions lie directly beneath the macula). Visual field defects corresponding to the location of the lesions may be detected. After several days, the lesions begin to clear from the center and resolve over subsequent weeks to months. The retinal pigment epithelium eventually adopts a mottled and slightly pale appearance. Rare, late signs include mild chorioretinal scarring and choroidal neovascularization.
Prevalence
APMPPE is rare
Significance
Vision returns to 6/9 or better within several weeks in the vast majority of patients.
Differential diagnosis
Serpiginous choroiditis; multiple evanescent white dot syndrome; birdshot choroidopathy; intraocular lymphoma; choroidal metastasis.
See also
Posterior uveitis.
Management
Imaging tests With intravenous fluorescein angiography, the lesions are typically hypofluorescent in the early phase and\ hyperfluorescent in the late phase. Upon resolution of the disease there is often a mottled pattern of fluorescence corresponding to the fundoscopy findings. Indocyanine green (ICG) angiography shows an absence of fluorescence in the early and late phases.
Other investigations In atypical cases, or in the presence of systemic symptoms, several further tests (such as screening
Fig. 4.1
Pale, ill-defined, yellowish patches at the posterior pole.
Fig. 4.2
Fluorescein angiogram, early venous phase (same patient): masking of choroidal perfusion.
blood tests for vasculitis) may be appropriate. Topical medications No treatment is required in most cases. Corticosteroid medications are indicated when there is marked visual impairment, or oral treatment for an associated systemic inflammatory condition. Cyclosporin is used in resistant cases.
Review Improvement in symptoms and signs may continue for up to 12 months. If review reveals marked chorioretinal scarring or choroidal atrophy, an alternative diagnosis – especially serpiginous chorioretinitis – should be considered.