Síndrome de Susac: Una causa poco frecuente de encefalopatía / Susac syndrome, a rare cause of encephalopathy

El síndrome de Susac es una enfermedad rara causada por oclusión autoinmune de la microvasculatura del cerebro, de la retina y del oído interno, lo que provoca la triada clínica característica de disfunción del sistema nervioso central, trastornos visuales y déficit vestíbulo-coclear. El diagnóstico se basa en las manifestaciones clínicas y en estudios complementarios que demuestren el compromiso de los tres sistemas. Existen diferentes tratamientos que incluyen combinaciones de varios fármacos inmunosupresores como corticoides, inmunoglobulina intravenosa, micofenolato mofetilo, entre otros. Presentamos el caso de una mujer de 26 años que manifestó hipoacusia izquierda, zumbidos y episodios de vértigo recurrente. Cuatro semanas después agregó visión borrosa bilateral, ataxia cerebelosa y encefalopatía. La resonancia magnética de cerebro mostró múltiples lesiones redondeadas hiperintensas en t2 y FLAIR (fluid-attenuated inversion recovery), hipointensas en t1 a nivel medial del cuerpo calloso, cápsula interna, cerebelo y pedúnculo cerebeloso medio derecho. La audiometría evidenció hipoacusia perceptual bilateral a predominio del oído izquierdo y en la angiografía por tomografía de coherencia óptica se observó obstrucción de arterias de la capa profunda de la retina. Se diagnosticó síndrome de Susac y se inició tratamiento con pulsos de metilprednisolona por 5 días y mantenimiento con micofenolato, revirtiendo totalmente la encefalopatía, con persistencia de leve ataxia e hipoacusia. Es importante conocer la triada clínica característica y los estudios complementarios necesarios para arribar al diagnóstico, ya que muchas veces se puede demorar el tratamiento inmunosupresor. Nuestro caso tuvo una excelente respuesta a los corticoides.

Susac syndrome is a rare disorder caused by autoimmune-mediated occlusions of microvessels in the brain, retina and inner ear. These occlusions lead to a characteristic clinical triad of central nervous system dysfunction, visual disturbances and vestibule-cochlear deficits. The diagnosis is based on clinical manifestations and complementary studies, which demonstrate the involvement of three systems. There are different treatments that include various immunosuppressive drugs combinations such as corticosteroids, intravenous immunoglobulin, mycophenolate mofetil, among others. We present the case of a 26-year-old woman with left hearing loss, tinnitus and episodes of recurrent vertigo, four weeks after bilateral blurred vision, cerebellar ataxia and encephalopathy. Magnetic resonance imaging of the brain showed multiple rounded hyperintense lesions in t2 and fluid-attenuated inversion recovery (FLAIR), hypointense in t1, at the middle level of the corpus callosum, internal capsule, cerebellum and right middle cerebellar peduncle. The audiometry evidenced bilateral perceptual hearing loss, predominantly in the left ear. Angiography by optical coherence tomography showed obstruction in the deep layer retina arteries. The Susac syndrome was diagnosed and treatment started with methylprednisolone pulses therapy, intravenously 1000 mg/ day for 5 days, followed by maintenance with mycophenolate, which completely reversed the encephalopathy, with persistence of mild ataxia and hearing loss. It is important to know the clinical triad characteristic and the complementary studies necessary to arrive at the diagnosis, since immunosuppressive treatment can often be delayed. Our case had an excellent response to corticosteroids.

Ensayo pictórico: diagnóstico diferencial radiológico en esclerosis múltiple / Pictory essay: radiological differential diagnosis of multiple sclerosis

La esclerosis múltiple (EM) es la enfermedad inflamatorio-desmielinizante del Sistema nervioso central más prevalente en adultos. La resonancia magnética (RM) juega un rol cada vez más importante en el estudio de esta patología, en especial en su diagnóstico precoz, por lo que la diferenciación imagenológica de variantes frecuentes e infrecuentes de EM con otras patologías de sustancia blanca que comprometen encéfalo y médula espinal es esencial. Mediante una revisión pictórica se ilustrarán características típicas en RM del compromiso por EM y de variantes menos habituales de lesión desmielinizante, y se ilustrarán hallazgos característicos de lesiones relacionadas a vasculopatías inflamatorias y no inflamatorias, encefalomielitis diseminada aguda (ADEM), neuromielitis óptica (NMO) y enfermedades vasculares de la médula espinal que pueden simular EM, con énfasis en el diagnóstico diferencial radiológico.

Multiple sclerosis (MS) is the most prevalent inflammatory-demyelinating disease of the central nervous system in adult population. Magnetic resonance imaging (MRI) has an increasingly important role, especially in early diagnosis, so the imaging differentiation of frequent and infrequent variants of MS with other white matter diseases of brain and spinal cord is essential. Through a pictorial essay we show typical MR features of MS and more infrequent variants of demyelinating lesions and illustrate characteristic imaging findings of inflammatory and non-inflammatory vasculopathies, acute disseminated encephalomyelitis (ADEM), neuromyelitis optica (NMO) and vascular diseases of spinal cord that may simulate MS, with emphasis on imaging differential diagnosis.

Susac's syndrome: isolated retinal artery occlusion after 10 years of remission / Síndrome de Susac: oclusão isolada da artéria retiniana após 10 anos de remissão

ABSTRACT Susac's syndrome, or microangiopathy of the retina, inner ear, and brain, is a rare condition characterized by the clinical triad of encephalopathy, branch retinal artery occlusion, and sensorineural hearing loss. The complete triad has been documented in 85% of reported cases. At clinical onset, the most common manifestations are central nervous system symptoms, followed by visual symptoms and hearing disturbances. Although the clinical course of Susac's syndrome is usually self-limiting, fluctuating, and monophasic, clinical polycyclic and chronic courses have also been described. Likewise, recurrences of the full triad after more than 10 years of remission have been reported. We describe a 21-year-old woman who presented with branch retinal artery occlusions and magnetic resonance imaging findings compatible with Susac's syndrome without objective hearing loss. After 10 years of remission, the patient complained of visual field loss due to new retinal ischemia. Neither other symptoms nor neuroimaging or audiometry pathologic findings were found during the clinical course.

RESUMO A síndrome de Susac, ou a micro angiopatia da retina, do ouvido interno e do cérebro, é uma condição rara caracterizada pela tríade clínica de encefalopatia, oclusão de ramo da artéria retiniana e perda de audição neuro-sensorial. A tríade completa é documentada em 85% dos casos registrados. No início dos sinais clínicos, a manifestação mais comum relaciona-se ao sistema nervoso central, seguida por sintomas visuais e distúrbios auditivos. Apesar do curso clínico da síndrome de Susac ser usualmente auto limitante, variável e monofásico, cursos clínicos policíclicos e crônicos têm sido também descritos. Do mesmo modo, recorrências da tríade completa após mais de 10 anos de remissão têm sido relatadas. Descrevemos o caso de uma mulher de 21 anos que apresentava oclusões de ramos da artéria retiniana e imagens por ressonância magnética compatíveis com a síndrome de Susac, sem comprometimento objetivo da audição. Dez anos após a remissão, a paciente queixou-se de perda de campo visual devido a uma nova isquemia da retina. Nenhum outro sintoma, ou neuroimagem ou achado audiométrico patológico foi observado durante o curso clínico.