In the current issue of JNNP, Kleffner and colleagues have published the first diagnostic criteria for diagnosing Susac syndrome based on clinical and paraclinical findings.
Susac syndrome is an uncommon disease characterized by the present of encephalopathy with or without focal neurological signs, branch retinal artery occlusion and neuro-sensorial hearing loss. Even though this clinical triad had been considered pathognomonic, only 13% of the patients presented at disease onset. The infrequent and clinically incomplete presentation of this syndrome usually leads to misdiagnosis, often diagnosed and treated as multiple sclerosis, therapy which may exacerbate Susac syndrome.
In this study, the interdisciplinary experts of the European Susac Consortium (EuSac) team have established a new diagnostic criteria for Susac syndrome based on a three steps process: (i) definition of a reference group of patients with Susac syndrome, (ii) selection of new diagnostic criteria based on the clinical and paraclinical findings (brain MRI, ophthalmological and vestibulocochlear tests) on the reference group and on the available literature cases and (iii) validation of the proposed criteria in a cohort of possible Susac syndrome (reported until 2012). After definition of the diagnostic criteria, more than 90% of Susac syndrome cases reported in the literature fulfilled the proposed criteria of probable or definitive, and 56% filled the criteria for definitive Susac syndrome. The authors conclude that these new criteria may help clinicians to make an earlier, accurate diagnosis of Susac syndrome, preventing the delay of treatment initiation.
The Susac syndrome was first described by John O. Susac in 1979 in two young women with the classic clinical triad. Since then exciting advances have been achieved regarding the clinical and paraclinical characterization of the syndrome and the pathophysiological mechanisms of the disease. Nowadays this syndrome is considered an autoimmune microangiopathy, affecting the precapillary arterioles of the brain, retina, and inner ear. Given the complexity of this syndrome, the creation of formal diagnostic criteria is relevant to improve the diagnostic process. These new criteria also emphasize the necessity of a multidisciplinary approach that includes the combined work of neurologists, neuroradiologists, ophthalmologists and otorhinolaryngologists. Although the primary pathogenic anti-antibody is yet to be discovered, precise immunosuppressive therapy results in significant clinical and radiological improvement, delaying disease progression and neurological disability. Further studies are needed to evaluate the use of these criteria prospectively. However in the meantime these criteria may aid the diagnostic process of patients with suspected Susac syndrome.
As such, this is a very interesting study, which provides valuable insights into the diagnosis of Susac syndrome.
Read more at http://jnnp.bmj.com/content/87/12/1287.full.pdf