Atypical Central Serous Chorioretinopathy

Central serous chorioretinopathy (CSCR) is an idiopathic chorioretinal disease which causes serous detachment in the neurosensory retina, which may also be accompanied by pigment epithelium detachment.¹Compared to the acute and chronic types of CSCR, bullous CSCR is rarely reported and is characterized by bullous retinal detachment in the inferior quadrants of the fundus.^2,3,4Although its pathophysiology is unknown, corticosteroids are known to be one of the major risk factors in the development of CSCR.^1,5,6,7,8The use of corticosteroids, especially in the treatment of systemic or ocular conditions may lead to acute emergence or exacerbation of CSCR.^5,6,7,8,9Atypical, bullous, or chronic type CSCR may be confused with other diseases that can cause intraocular inflammation such as Vogt-Koyanagi-Harada (VKH) disease, posterior scleritis, sympathetic ophthalmia, multifocal choroiditis, and serpiginous choroiditis.^5,9Corticosteroid treatment due to the misdiagnosis of posterior uveitis leads to the exacerbation of CSCR symptoms.⁹

In the present study, we present the follow-up and treatment response of a patient diagnosed with bullous CSCR who was treated for an extended period with corticosteroids for a diagnosis of VKH.

Although it is not fully understood how corticosteroids induce or exacerbate CSCR, various mechanisms have been implicated in the development of the disease. Exogenous or endogenous hypercortisolemia elevates catecholamine levels, creates a mineralocorticoid effect, or induces thrombocyte aggregation, which increase choriocapillaris permeability and RPE decompensation, leading to CSCR.^1,9The development of CSCR is independent of the corticosteroid type, dose or route of administration.⁹Gass and Little⁵reported bilateral bullous CSCR in a patient who was administered systemic and sub-Tenon corticosteroid due to a misdiagnosis of choroiditis; the serous detachments regressed after discontinuing the drug and treating with laser photocoagulation. In a series reporting the long-term follow-up outcomes of 25 patients with bullous CSCR, 4 patients (16%) developed this severe form of CSCR in which the areas of serous detachment healed with residual scarring or atrophy after drug discontinuation and treatment.⁴

The findings of bullous CSCR may be confused with uveal effusion, metastatic carcinoma or lymphoma, rhegmatogenous retinal detachment, and diseases that cause inflammation such as VKH disease, multifocal choroiditis, and sympathetic ophthalmia, and misdiagnosis results in unnecessary tests and treatments.^5,9Kang et al.¹⁰observed progression of bullous detachment in a 47-year-old male patient who was treated with systemic corticosteroids for a prediagnosis of VKH; they subsequently discontinued the medication and successfully treated the patient with vitrectomy and internal subretinal fluid drainage. Gao and Li¹¹reported a patient with a previous history of CSCR whose disease converted to the bullous form after being treated with systemic methylprednisolone due to misdiagnosis of VKH. A multimodal imaging approach utilizing FA, ICGA, and spectral domain-OCT is important in the differential diagnosis and follow-up of the disease.¹²CSCR is most commonly mistaken for the exudative retinal detachment seen in the acute phase of VKH. Findings that facilitate the diagnosis of CSCR are an absence of cells in the anterior chamber or vitreous and no sign of optic disc edema on examination; no choroidal thickening in USG; an absence of optic disc staining in late phases of FA; and observing multifocal hyperpermeability instead of diffuse hyperpermeability and the absence of hypofluorescence spots or optic disc staining on ICGA.⁹Other findings that support CSCR diagnosis are the presence of dome-shaped serous detachment on OCT, subretinal precipitates, localized fibrin reaction, presence of RPE detachment and irregularities, no visible subretinal septa, fundus autofluorescence showing hypoautofluorescence in the area of subretinal fluid, and hyperautofluorescence corresponding with areas of leakage on FA.⁹Because choroid thickness increases in both VKH disease and CSCR, noninvasive EDI-OCT examination is not useful for differentiating between these two entities.¹³However, corticosteroid treatment provides favorable results in VKH ocular involvement, but may exacerbate ocular symptoms in CSCR.⁹In our study, our patient also received an initial diagnosis of VKH due to the presence of presumed serous retinal detachment, and was administered systemic and periocular corticosteroid therapy for one year. These treatments not only exacerbated the CSCR and induced its transformation to the bullous form, but also caused systemic problems such as Cushing’s syndrome.

Due to its angio-occlusive effect, PDT leads to narrowing of the choroidal vessels and thereby a reduction in choroidal exudation, as well as reshaping of choroidal vessels.¹⁴Low-fluence or low-dose PDT is used in CSCR to avoid the potential complications of standard PDT, such as RPE atrophy, choroidal ischemia, and secondary choroidal neovascularization. Successful outcomes have been reported in studies using these techniques.^15,16Although there are no randomized, controlled studies in the literature, some studies have shown that oral eplerenone, a mineralocorticoid receptor antagonist, decreases subretinal fluid in chronic CSCR and is a promising treatment method for the future.^17,18Because our patient had very advanced stage disease, we combined available treatment methods such as low-fluence PDT, focal laser photocoagulation, and oral eplerenone, and the patient responded well within a short period.

In conclusion, bullous type CSCR may be confused with ocular symptoms of acute VKH disease. Corticosteroid therapy administered for a misdiagnosis of intraocular inflammation may exacerbate CSCR and lead to irreversible damage. Atypical bullous CSCR must be considered in cases of serous retinal detachment, and the use of multimodal imaging methods in addition to detailed ophthalmologic and systemic examinations will facilitate an accurate diagnosis before giving corticosteroids.