Case Presentation: A previously healthy 19-year-old woman presented to the hospital for a persistent headache with photophobia, nausea, and vomiting that started one week prior. Previously, she was evaluated in the emergency department three times with a negative brain MRI with contrast as well as MRI angiography and venography. On admission, given lack of improvement, an LP was performed which showed leukocytic pleocytosis (333 WBCs, 75% lymphocytes), elevated protein (77mg/dL), and increased opening pressure (39 cm H20) consistent with aseptic meningitis. Autoimmune work-up and infectious work-up were negative including LP culture and arbovirus and HSV PCR. She had no evidence of immunodeficiency. Two weeks after her initial headache started, worsening blurry vision developed. The ophthalmologic exam showed bilateral 2+ papilledema and peripheral vasculitis with areas of hemorrhage and whitening. She was started on pulse steroids. She had a negative anterior chamber paracentesis. All further infectious and systemic autoimmune etiologies continued to be negative. CT of the abdomen and pelvis was unremarkable. Repeat LP showed improvement of leukocytosis pleocytosis (47WBCs, 94% lymphocytes) with normal opening pressure and normal protein (25mg/dl). However visual acuity continued to decrease to 20/70 bilaterally. The initial cause of her aseptic meningitis remained unclear but was likely viral in origin. Her worsening visual acuity and optic exam with no systematic signature of disease was consistent with idiopathic frosted branch angiitis (FBA). She was treated with a second course of pulse steroids followed by a prednisone taper. Repeat eye exam on discharge showed improvement of vision and retinal vasculitis, but worsening of perivascular vitritis prompting initiation of methotrexate after discharge.
Discussion: Here we present a case of a patient with initial aseptic meningitis who was found to have idiopathic FBA. The differential for retinal vasculitis is broad including infection, autoimmune, primary neurological, malignancy, and other ocular pathologies. The patient’s retinal vasculitis involving both arteries and veins with broad perivascular retinal whitening with few peripheral hemorrhages was consistent with FBA. There have been around 50 total case reports of FBA. Although optimal treatment is unclear, symptom improvement and even resolution has been seen with systemic steroids. Treatment response is oten rapid, but occasionally recovery is prolonged,1 FBA has been found to be secondary to many infectious etiologies including HSV, EBV, VZV, CMV, and COVID-19 as well as SLE.2,3 The exact cause of FBA is unknown but may be a hypersensitivity reaction to an infection involving immune complex deposition. 1 Vitritis, in addition to retinal vasculitis, has been reported in other cases of idiopathic FBA.
Conclusions: Ocular vasculitis without other systemic symptoms post aseptic meningitis may represent idiopathic FBA. Diagnosis and treatment of FBA require an inter-disciplinary team of neurology, ophthalmology, infectious disease, and rheumatology. In this case, recognizing the time course of the disease, lack of other signs of systemic autoimmune disease, and an extensive negative work-up helped establish a rare diagnosis.
