Frosted branch angiitis due to retinal vasculitis that was associated with antisynthetase syndrome
B. Diagnostic anterior chamber paracentesis and intravitreal foscarnet
Despite the patient’s clinical presentation being suggestive of autoimmune retinal vasculitis, the most appropriate initial step is to rule out viral retinitis with an anterior chamber paracentesis and empirical treatment with intravitreal foscarnet (choice B) given the patient’s immunocompromised status. Escalating immunosuppression (choice A) is inappropriate before excluding infectious etiologies. Peripheral blood smear and flow cytometry (choice C) for clonality assessment or positron emission tomography–computed tomography (choice D) for occult malignancy screening are inappropriate in the short-term setting.
Frosted branch angiitis is a form of retinal vasculitis that is characterized by diffuse vascular sheathing and various degrees of intraocular inflammation.1 Idiopathic frosted branch angiitis occurs in otherwise healthy patients in their first or third decade of life following a viral illness and has a favorable prognosis with systemic steroid therapy.1- 3 Secondary frosted branch angiitis occurs in patients with an underlying infection, such as cytomegalovirus, herpes simplex virus, varicella-zoster virus, toxoplasmosis, tuberculosis, and syphilis, or inflammatory disease, such as Crohn disease, granulomatosis with polyangiitis, sarcoidosis, systemic lupus erythematosus, antiphospholipid syndrome, Behçet disease, multiple sclerosis, familial Mediterranean fever, or drug-induced antineutrophil cytoplasmic antibody vasculitis,1,3- 5 and is thought to result from immune complex deposition. The frosted branchlike appearance may be associated with leukemia or lymphoma due to vessel wall infiltration with malignant cells. This patient had a normal whole-blood flow cytometry. Frosted branch angiitis may also present as a paraneoplastic manifestation of Hodgkin lymphoma6; however, this patient had an unremarkable whole-body positron emission tomography–computed tomography.