Retinal Vasculitis as a Rare Presentation of Microscopic Polyangiitis.

Microscopic polyangiitis (MPA) is a rare, autoimmune, small-vessel vasculitis usually described with the presence of perinuclear antineutrophil cytoplasmic antibodies (p-ANCA). It encompasses a broad spectrum of clinical features, including fatigue, weight loss, fever, arthralgia, skin lesions, and involvement of the lungs or kidneys. Ocular manifestations, however, are extremely rare. We report a case of a 60-year-old Caucasian male who presented with sudden left-hand weakness, fever, and amaurosis fugax. He also complained of fatigue and stocking-glove paresthesia over the preceding two months. Neurological evaluation excluded acute stroke, and ophthalmologic examination, supported by fluorescein angiography, revealed mild right-sided temporal retinal vasculitis without other retinal changes. Laboratory investigations demonstrated inflammatory anemia, elevated erythrocyte sedimentation rate, mild proteinuria, autoimmune hypothyroidism, and positive p-ANCA-myeloperoxidase (MPO) with a nuclear-dense anti-nuclear antibodies (ANA) pattern. Renal biopsy confirmed crescentic vasculitis, while nerve biopsy indicated small-vessel vasculitis. Treatment with prednisolone and azathioprine resulted in clinical improvement. This case highlights retinal vasculitis as a rare manifestation of MPA.