Endocrine Abstracts

Introduction: Susac syndrome is a rare endotheliopathy causing micro-ischemic damage to vessels in the brain, ears, and eyes. While the underlying aetiology of this disease remains unknown, it is widely believed that observed clinical manifestations result of an autoimmune endotheliopathy. Herein we report a case of Basedow’s disease associated to a scarce condition: Susac syndrome.

Observation: Our patient is a 48-year-old woman, who was admitted for chronic holocranial headache, without blurred vision nor vomiting. Physical examination only revealed a right hemiparesis. The brain MRI highlighted temporal and periventricular oval demyelinating lesions with T2 hypersignal and T1 hyposignal. These lesions were also described in the corpus callosum. An audiogram was performed and showed a bilateral and symmetric perceptive deafness. Ophthalmologic examination described a decreased visual acuity. Retinal fluorescein angiography showed bilateral and diffuse vasculitis. Somatosensory evoked potentials had a slightly decreased amplitude. Visual and auditory evoked potentials were normal. Cerebrospinal fluid testing did not show any abnormality. Therefore, the diagnosis of Susac syndrome was made. Thrombophilia testing and antinuclear antibodies were negative. She had a biological inflammatory syndrome and low levels of TSH. The thyroid scintigraphy was compatible with a Basedow’s disease. We started treatment with radioactive iodine. Treatment of Susac syndrome consisted of three boli of methylprednisolone (1g/day for 3 days). Oral corticotherapy was then prescribed, with a good clinical and biological evolution.

Conclusion: Susac syndrome is caused by a microangiopathy that gives the classic clinical triad of subacute encephalopathy, visual loss secondary to retinal branch occlusions, and sensorineural hearing loss. Given autoimmune part of Susac aetiology, association to other autoimmune condition, especially Basedow disease, must be actively sought. Early therapy may reduce sequelae and improve recovery.