In this report, we describe a case of sequential bilateral neuroretinitis associated with prepapillary inflammatory vitreous exudate (PIVE) secondary to BD documented with SS OCT and OCTA.
Similar optic nerve involvement has been previously described as an uncommon finding in active BD uveitis [5,6,7]. It has been variably termed as prepapillary inflammatory vitreous opacity, exudation, condensation, or infiltrate. There are only a few reports that specifically addressed this finding in literature [5, 7]. Commonly, PIVE occurred among patients with a known history of BD [5,6,7]. Conversely, in our patient, the initial unilateral neuroretinitis and associated PIVE occurred in the absence of relevant extraocular signs for BD, along with a positive toxoplasmosis serology, leading to a misdiagnosis of presumed toxoplasmic neuroretinitis. One year later, a similar neuroretinitis with transient PIVE developed in the fellow eye and typical mucocutaneous lesions became evident only at that time. The patient therefore was diagnosed with definite BD and accordingly treated.
The PIVE occurred in our patient in association with marked optic disc and peripapillary infiltration. These localized optic disc changes were observed in the absence of significant inflammatory changes elsewhere in the fundus. Conversely, in previously reported cases [5,6,7], patients had bilateral panuveitis with retinal vasculitis concomitant to the unilateral PIVE.
Our case, consistent with previous data, shows that the PIVE and underlying optic disc and peripapillary infiltration rapidly resolve, with improvement of visual acuity.
SS OCT was useful in confirming the diagnosis of PIVE in both sequentially involved eyes by showing a characteristic prepapillary hyperreflective “mushroom-shaped” lesion. It also allowed us to detect an associated serous retinal detachment and to exclude any obvious peripapillary or subfoveal choroidal changes. SS OCTA showed at the acute phase a hypointense prepapillary area due to shadowing from the PIVE. This hypointense area was found to characteristically decrease in size while scanning deeper, reflecting the “mushroom-shaped” hyperreflectivity seen on SS OCT. SS OCTA also allowed us to detect subclinical peripapillary vascular involvement with retinal hypervascularity and increased vessel density which gradually resolved over time. In addition to that, the initially involved left eye demonstrated a peripapillary superotemporal area of signal loss which could explain the subsequent development of RNFL defects in the same eye. Localized RNFL defects have been considered in BD uveitis as an indicator of past retinal or optic nerve involvement and as a helpful ocular diagnostic clue [8]. Our results, consistent with previous data [3, 8], show that RNFL defects can be easily detectable by fundus examination, but OCT and RNFL thickness analyzer are useful in confirming the diagnosis and detecting subclinical RNFL alterations.
The bilateral sequential PIVE in our patient likely occurred due to the spread of inflammation from primary severe optic nerve infiltration [7].
The « mushroom-shaped » or « funnel-shaped » OCT pattern of BD-associated PIVE might be due to polymorphic leukocytic infiltration into the enlarged end of Cloquet’s canal [5, 7].
This report shows that bilateral sequential PIVE, indicative of severe neuroretinitis, can occur before other ocular and systemic manifestations of BD become evident, and this may lead to mistakes in diagnosis and management. Multimodal imaging including FFA, OCT, and OCTA can provide valuable information for the definitive diagnosis and appropriate management of BD-associated PIVE and underlying neuroretinitis.