[Susac Syndrome: A Diagnostic Chameleon]. / Susac-Syndrom: ein diagnostisches Chamäleon.

Susac's syndrome (SuS) is a rare, probably autoimmune endotheliopathy of the central nervous system, retina and inner ear. It is characterized by a clinical triad of encephalopathy, branch retinal artery occlusions (BRAOs) and sensorineural hearing loss. To date, more than 300 cases of SuS have been reported in the literature. However, SuS remains an under- and misdiagnosed entity in the clinical setting. This report presents an exemplary case of a patient, who was initially misdiagnosed with relapsing-remitting multiple sclerosis. At initial presentation, the patient did not demonstrate the complete clinical triad, and the interval between symptom onset and diagnosis was 4 months. Typical diagnostic features, which enabled the diagnosis of SuS were: a) MRI findings with T2-hyperintense snowball-like lesions of the corpus callosum and subcortical white matter and hyperintense lesions in diffusionweighted imaging with reduced apparent diffusion coefficient; b) BRAOs and vessel wall hyperfluorescence in fluorescein angiography and a significant thickness reduction of the inner retinal layers in optical coherence tomography; c) bilateral sensorineural hearing loss. The patient was aggressively treated with cyclophosphamide, rituximab, glucocorticoids and acetylsalicylic acid with a good response to therapy. This report draws attention to the need to take SuS into consideration in the differential diagnosis at the interface of neurological, psychiatric, ophthalmological and otorhinolaryngological disorders. As SuS may result in severe and persistent neurological deficits, an interdisciplinary collaboration is fundamental for the prompt diagnosis and initiation of adequate immunosuppressive treatment.

[Retinovascular Findings in Susac's Syndrome]. / Retinovaskuläre Zeichen des Susac-Syndroms.

BACKGROUND: Susac syndrome is a vasculopathy affecting the central nervous system, retina and cochlea leading to the triad encephalopathy, branch retinal artery occlusions and hearing loss. To date, about 300 cases have been described in the literature. PATIENTS/METHODS: Three patients with confirmed Susac syndrome were evaluated for disease-specific retinal pathologies. In addition, the overall history of the disease is presented to put the ophthalmological pathology into context. RESULTS: All three cases showed a retinal occlusive microangiopathy with branch retinal artery occlusions. MRI imaging revealed snowball-like lesions of the corpus callosum in two of three cases. At the initial presentation not all criteria of the disease-specific triad encephalopathy, branch retinal artery occlusions, and hearing loss were fulfilled in the three patients. CONCLUSION: Interdisciplinary collaboration between neurologists, otorhinolaryngologists and ophthalmologists is mandatory to establish the diagnosis of the disease. The occurrence of the characteristic retinal pathology with small artery occlusions and a segmental vasculopathy should always lead to the differential diagnosis of Susac syndrome.

Thermotropic properties of phosphatidylcholine nanodiscs bounded by styrene-maleic acid copolymers.

Styrene-maleic acid copolymers (SMA) have been gaining interest in the field of membrane research due to their ability to solubilize membranes into nanodics. The SMA molecules act as an amphipathic belt that surrounds the nanodiscs, whereby the hydrophobic styrene moieties can insert in between the lipid acyl chains. Here we used SMA variants with different styrene-to-maleic acid ratio (i.e. 2:1, 3:1 and 4:1) to investigate how lipid packing in the nanodiscs is affected by the presence of the polymers and how it depends on polymer composition. This was done by analyzing the thermotropic properties of a series of saturated phosphatidylcholines in nanodiscs using laurdan fluorescence and differential scanning calorimetry. In all cases it was found that the temperature of the main phase transition (Tm) of the lipids in the nanodiscs is downshifted and that its cooperativity is strongly reduced as compared to the situation in vesicles. These effects were least pronounced for lipids in nanodiscs bounded by SMA 2:1. Unexpected trends were observed for the calorimetric enthalpy of the transition, suggesting that the polymer itself contributes, possibly by rearranging around the nanodiscs when the lipids adopt the fluid phase. Finally, distinct differences in morphology were observed for nanodiscs at relatively high polymer concentrations, depending on the SMA variant used. Overall, the results suggest that the extent of preservation of native thermodynamic properties of the lipids as well as the stability of the nanodiscs at high polymer concentrations is better for SMA 2:1 than for the other SMA variants.

[Retinovascular findings in Susac's syndrome]. / Retinovaskuläre Zeichen des Susac-Syndroms.

BACKGROUND: Susac syndrome is a vasculopathy affecting the central nervous system, retina and cochlea leading to the triad encephalopathy, branch retinal artery occlusions and hearing loss. To date, about 300 cases have been described in the literature. PATIENTS/METHODS: Three patients with confirmed Susac syndrome were evaluated for disease-specific retinal pathologies. In addition, the overall history of the disease is presented to put the ophthalmological pathology into context. RESULTS: All three cases showed a retinal occlusive microangiopathy with branch retinal artery occlusions. MRI imaging revealed snowball-like lesions of the corpus callosum in two of three cases. At the initial presentation not all criteria of the disease-specific triad encephalopathy, branch retinal artery occlusions, and hearing loss were fulfilled in the three patients. CONCLUSION: Interdisciplinary collaboration between neurologists, otorhinolaryngologists and ophthalmologists is mandatory to establish the diagnosis of the disease. The occurrence of the characteristic retinal pathology with small artery occlusions and a segmental vasculopathy should always lead to the differential diagnosis of Susac syndrome.