SECTION EDITOR: BENNIE H. JENG, MD, MS
C. Obtain further testing to rule out infectious etiologies
In an otherwise healthy young boy with 9-month history of decreased visual acuity and examination findings of vitritis, vitreous hemorrhage, retinal vasculitis, neovascularizations, arteriolar aneurysms, capillary nonperfusion, and neuroretinitis, the first step would be to undergo a workup to rule out treatable infectious etiologies. He had an extensive workup that was negative for herpes simplex virus, varicella zoster virus, fungal disease, cytomegalovirus, Epstein-Barr virus, toxoplasmosis, toxocariasis, cysticercosis, syphilis, tuberculosis, and tick-borne illnesses. This patient's clinical picture was concerning for idiopathic retinal vasculitis, aneurysms, and neuroretinitis (IRVAN). However, given that a diagnosis of IRVAN is a diagnosis of exclusion, further investigation was pursued to exclude inflammatory etiologies such as systemic lupus erythematosis, Takayasu disease, Behçet syndrome, and sarcoidosis. An inflammatory disease workup revealed elevated angiotensin-converting enzyme levels of 114 and 117 U/L (to convert to nanokatals per liter, multiply by 16.667), both markedly abnormal even compared with pediatric reference levels, indicating possible sarcoidosis. This finding prompted genetic testing, the results of which were positive for 2 mutations within chromosome 16q12 on the NOD2 /CARD15 gene. These mutations, R702W and IVS8+158C>T, have been associated with Blau syndrome and Crohn disease. Given these genetic mutations, in conjunction with the patient's elevated angiotensin-converting enzyme levels, he received a diagnosis of Blau syndrome. Of note, the results of computed tomography of his chest and magnetic resonance imaging/magnetic resonance angiography of his head and neck were unremarkable. Peripheral laser photocoagulation was performed for each eye, and he received a periocular triamcinolone injection in his right eye. Since treatment, the patient's visual acuity had improved to 20/150 OD and stabilized to 20/40 OS. Further genetic testing for his family is pending.
Retinal Vasculitis, Aneurysms, and Neovascularization in Blau Syndrome—Diagnosis. JAMA Ophthalmol. 2013;131(5):680. doi:10.1001/jamaophthalmol.2013.413b