Susac Syndrome: A differential diagnosis of white matter lesions.

INTRODUCTION: Susac Syndrome is an autoimmune endotheliopathy affecting capillaries and precapillary arterioles of the brain, inner ear and retina. The classic symptom triad includes visual disturbances, hypoacusia, and encephalopathy, but is rarely fully manifest at onset. The syndrome typically follows an active fluctuating monophasic course. Typical imaging findings on brain magnetic resonance show central fiber microischemias/microinfarctions of the corpus callosum known as "snow balls", as well as lineal infarcts and upper callosal fiber involvement. Fluorescein angiography and tonal audiometry are important tools to confirm diagnosis, even in patients who are asymptomatic for visual or auditory disturbances. We describe 8 patients with Susac Syndrome treated at our center and compare findings to those of other published case series. METHODS: Eight adults with Susac Syndrome diagnosed between January 2007 and August 2016 at our center, in Buenos Aires, Argentina are described. Magnetic Brain Resonance, fluorescein angiography, tonal audiometry, a complete serologic battery and lumbar puncture were performed to all patients. RESULTS: The majority of patients were males, and average age at diagnosis was 37.5 years (range: 22-52 yrs). Two patients presented full clinical triad at onset, while the remaining developed visual and/or auditory disturbances later during the course of disease. All cases manifested varied neurological symptoms including pyramidal and/or sensory tract symptoms, amnesic disorders, ataxia and vertigo. Psychiatric manifestations such as disinhibition, aggressive behavior, paranoid ideation and hallucinations were also present. Seven patients suffered at least one relapse. Typical central corpus callosum fiber ischemias/infarcts, also known as snowball lesions were visible in all patients. Spokes, icicles, periventricular lesions and internal capsule "string of beads" patterns were observed on diffusion weighted images. Four cases presented fornix microischemias/microinfarctions, 5 juxtacortical involvement and 3 infratentorial infarcts. Leptomeningeal involvement was evident in only 1 patient after rabies vaccination. Fluorescein angiography was abnormal in 7 cases. Tonal audiometry revealed unilateral hypoacusia in 5 patients, 3 with low frequency hearing loss. Immunosuppressive treatment was indicated in all cases. Patient follow up ranged between 6 months and 9 years, only 1 patient was lost to follow up after three years. CONCLUSION: Susac Syndrome is probably both underdiagnosed and misdiagnosed. Early and aggressive immunosuppressive treatment is indicated in order to prevent potential disabilities.

Asociación entre síndromes neurológicos y arbovirus en la ciudad de Buenos Aires: relación entre el Síndrome de Guillain Barre, Encefalitis y Mielitis con el virus del Zika, Dengue y Chikungunya / Association between neurological syndromes and arboviruses in the city of Buenos Aires: relationship between Guillain Barre Syndrome, Encephalitis and Myelitis with Zika, Dengue and Chikungunya viruses

INTRODUCCIÓN Las infecciones por arbovirus se consideran actualmente una pandemia en Argentina, existiendo un aumento significativo de la incidencia de las mismas, con respecto a años anteriores. Virus como el Zika (ZIKV), Dengue (DENV) y Chikungunya (CHIKV) se han asociado recientemente a diferentes síndromes neurológicos, principalmente con el Síndrome de Guillain Barré (SGB) y en menor medida con las encefalitis infecciosas (EI) y las mielitis transversas agudas (MTA). OBJETIVO Analizar la asociación existente entre el SGB, EI y MTA, con infecciones secundarias a arbovirus en pacientes internados de la ciudad de Buenos Aires evaluados en FLENI. METODOLOGÍA Estudio prospectivo de cohorte, en el cual se incluyeron todos los pacientes mayores de 18 años de edad con diagnóstico de SGB, EI o MTA infecciosa que fueran evaluados en FLENI desde el 1/1/17 al 31/12/17. Se tomaron muestras de suero y/o líquido cefalorraquídeo, se realizó test de ELISA para detección de anticuerpos contra ZIKV, DENV y CHIKV. Se registraron y realizó el análisis estadístico de variables epidemiológicas, clínicas y métodos complementarios de ambos grupos. Se compararon resultados de incidencia en 2017, con respecto a los últimos 10 años en FLENI. RESULTADOS Se incluyeron un total de 39 pacientes con diagnóstico de SGB (n=17), EI (n=18) y MTA (n=4). En 2 casos de SGB se obtuvo serología positiva para ZIKV y 2 casos de EI presentaron positividad para DENV. Durante el período comprendido entre 2015-2017 se observó un aumento de la incidencia de casos de SGB en comparación con años anteriores. DISCUSIÓN En la presente cohorte, la incidencia de casos de SGB, EI y MTA asociados a infecciones por arbovirus fue relativamente baja. Sin embargo, los casos secundarios a infecciones por dichos virus mostraron características clínicas diferenciales. Consideramos que la vigilancia epidemiológica de los síndromes neurológicos asociados a infecciones por arbovirus es fundamental para poder comprender la magnitud del problema a nivel nacional