Case Report: Neuroretinitis versus hypertensive retinopathy secondary to Alport syndrome.

Introduction: Alport syndrome (AS) is an inherited disease caused by the absence of type IV collagen from glomerular, cochlear, and ocular basement membranes. Ocular manifestations of AS include corneal opacity, peripheral and central fleck retinopathy, and temporal thinning on OCT. These findings in AS usually do not cause any vision loss. We report a case of bilateral vision loss with optic disc edema, macular edema, and macular star figure in AS. Case description: A 27-year-old woman presented with progressive, painless bilateral blurry vision over 2 weeks. She had genetically confirmed X-linked COL4A5 Alport syndrome and uncontrolled hypertension despite four antihypertensive medications. Visual acuity was 20/50 OU. Ishihara color testing was 6/14 OD and 2/14 OS. Fundoscopy showed moderate optic disc edema, a complete macular star, and tortuous vessel OU. Humphrey visual fields revealed severe constriction (mean deviation was -17.65 dB OS and -21.98 dB OD). Blood pressure was 163/93 mm Hg. OCT showed a peripapillary RNFL of 245 μm OD and 204 μm OS. MRI indicated an enlarged, partially empty sella and bilateral patulous optic nerve sheath. Lumbar puncture opening pressure was 13 cm H₂O with mildly elevated CSF protein and no pleocytosis. Infectious and inflammatory neuroretinitis workup was negative. She was started on acetazolamide 250 mg twice daily and transitioned to hemodialysis. After 9 months, vision improved to 20/30 OU, color plates to 10/14 OD and 8/14 OS, and OCT RNFL to 139 μm OD and 128 μm OS. Visual fields improved (mean deviation -3.13 dB OS, -3.8 dB OD). Conclusion: We consider the possibility of hypertensive retinopathy or idiopathic neuroretinitis in this patient with Alport syndrome. Given the disproportionate degree of macular edema and prominent macular star, in the absence of common manifestations of hypertensive retinopathy such as retinal hemorrhages or hard exudates, we suspect a possible superimposed neuroretinitis-like exudative mechanism driven by the absence of type IV collagen, providing structural support in Alport syndrome patients. This complex symptom presentation, to our knowledge, has never been described in the context of Alport syndrome. Further research is needed to better understand the relationship between Alport-related renal disease, hypertensive retinopathy, and neuroretinitis.