Peripapillary retinal lesions: Is it multiple evanescent white dot syndrome?

In recent years, the clinical spectrum of multiple evanescent white dot syndrome has widened. Originally it was described to be unilateral with lesions involving the retinal pigment epithelium and outer retina at the posterior pole. Overlap of this entity with other white dot syndrome was seen. However, cases on atypical presentation of white dot syndrome have been described.[1] Gass et al.[2] proposed that optic disc margin is a site for pathogen invasion. An alternate pathophysiology of multiple evanescent white dot syndrome (MEWDS) is sequential sublethal infection of photoreceptors via blood-borne pathogens and spreading to the nearby cells. The optic disc swelling and the peripapillary lesions reported in MEWDS suggest that this site is important in the early stages of the disease. This could be responsible for symptoms such as loss of vision, scotoma, and photopsia.[3] Joo et al.[4] described centrifugal propagation of retinal spots in the nasal retina outside the major vascular arcade probably due to the alternate pathophysiology of MEWDS, as described previously [Table 1].Table 1: Reports on atypical presentations of MEWDSEarly stage of MEWDS is underdiagnosed due to the mild symptoms and delay in referral to the ophthalmologist. Due to the absence of clinical signs in the early stage of MEWDS, multimodal imaging is delayed. Cahuzac et al.[5] described optical coherence tomography within one week of onset of ocular symptoms. They reported that ellipsoid zone disruption started simultaneously around the optic nerve and in a very restricted submacular area before extending diffusely. This indicates that the peripapillary area around the optic nerve is affected prior to the submacular area. Vela et al.[5] reported an unusual presentation of MEWDS with circumpapillary retinal white lesions and absence of optic disc edema and foveal granularity. Due to the transient nature of MEWDS, these peripapillary lesions are common in the early stage of the disease. Ray and Loewenstein[7] reported the initial manifestation of peripapillary outer retina or retinal pigment epithelium involvement centered around the optic nerve. Subsequently, the lesions evolved into more typical MEWDS findings with blurring of disc margin and deep retinal white dots surrounding the paramacular area with foveal sparing. Luttrull et al.[8] reported a giant white spot seen in their patient unlike the typical white dots seen in MEWDS. Due to the atypical findings, a diagnosis other than MEWDS was considered. This led to initial misdiagnosis, investigations, and treatment. Jampol et al.[9] described a similar case of MEWDS. The large geographic peripapillary lesion represents a confluence of typical MEWDS lesions. These patients have severe cases of the disease. The initial appearance of this peripapillary lesion can make diagnosis of MEWDS difficult. This can lead to inappropriate treatment. Therefore, ophthalmologists should be aware of this early stage of MEWDS. This will avoid initial misdiagnosis in a self-limiting disease.