[Susac syndrome: variable onset modes and disease courses: two case reports]

Susac syndrome is a rare microangiopathy of unknown etiology, which involves the clinical triad of encephalopathy, visual loss, and hearing loss. Several onset and progression patterns are possible.

Case 1: a 43-year-old woman developed subacute encephalopathy, which had not been diagnosed and had been evolving for 2 months, as well as left sensorineural hearing loss. The fundus exam found central artery branch occlusion in the left retina. The treatment was based on corticosteroids combined with cyclophosphamide and immunoglobulins. Angiographic monitoring revealed persistent asymptomatic arterial alterations despite positive neurological progression. Case 2: a 27-year-old woman presented visual loss in the right eye after recurrent neurological episodes. The triad was completed by deafness in the right ear. Treatment with corticosteroids led to favorable neurological progression and stabilized the ophthalmologic symptoms.

This syndrome preferentially affects young women. The nearly constant neurological symptoms can differ. Branch occlusions are frequently bilateral and often come with the appearance of vasculitis. Deafness is bilateral, asymmetrical, and of endocochlear origin. Brain MRI shows lesions of the corpus callosum that are distinctive of the syndrome. The disease mainly evolves in a monocyclic way, self-limited in time, and it rarely becomes chronic. Treatment, which has not been codified to date, is based on corticosteroids and, in severe cases, immunosuppressive drugs. Other therapies have not proved to be effective.

The diagnosis is based on the triad of neurological, ophthalmic, and ENT damage, but sometimes it can be difficult to formulate because of the chronology of symptom onset. Neurological damage, the first manifestation, will help make therapeutic decisions.