Ophthalmological Outcomes in Patients with Susac Syndrome.

BACKGROUND: To report ophthalmological outcomes and treatment regimen in patients with Susac syndrome. METHODS: This is a retrospective analysis of patients with Susac syndrome treated between November 2015 and March 2023. Multimodal imaging findings, ophthalmic examination data, information on neurological and sensorineural involvement, and therapeutic regimen were reviewed. Visual acuity was recorded as the logarithm of the minimum angle of resolution (logMAR). Ophthalmological manifestations and disease severity were assessed using the previously described clinical activity score (CAS). RESULTS: Ten patients with Susac syndrome m : f = 5 : 5 were identified. The mean follow-up time was 31.2 ± 23.3 months (range 1 to 78 months). The mean age was 41.4 ± 13.8 years (range 21 to 59 years). At baseline, corrected distance visual acuity (CDVA) was 0.03 ± 0.08 logMAR. At the last follow-up, CDVA improved to 0.00 ± 0.03 logMAR (p = 0.029). Three of 20 eyes showed an improvement of 5 letters, while no loss of visual acuity was recorded during the follow-up time. Baseline CAS was 10.65 ± 12.69, and CAS at the last follow-up was 5.15 ± 5.49 (p = 0.068). Except for one patient, all were initially treated with intravenous (i. v.) steroids and subsequent oral tapering. Depending on the treatment response, cyclophosphamide (n = 4), i. v. immunoglobulins (IVIGs) (n = 4), anti-CD20 antibodies (n = 3), or plasmapheresis (n = 1) were applied. All patients under treatment for more than 1 month (n = 9) showed improvement in CAS and CDVA. CONCLUSION: Susac syndrome is a rare autoimmune vascular endotheliopathy. Treatment of Susac syndrome appears to result in improving CAS and CDVA. The majority of patients, in addition to the systemic steroids, required systemic immunosuppressive agents. Interdisciplinary communication is crucial to reduce the time to diagnosis and initiation of therapy in patients with Susac syndrome.

Clinical Characterization and Ancillary Tests in Susac Syndrome: A Systematic Review.

Susac syndrome (SuS) is an orphan microangiopathic disease characterized by a triad of encephalopathy, visual disturbances due to branch retinal artery occlusions, and sensorineuronal hearing loss. Our previous systematic review on all cases of SuS reported until 2012 allowed for a better understanding of clinical presentation and diagnostic findings. Based on these data, we suggested diagnostic criteria in 2016 to allow early diagnosis and treatment of SuS. In view of the accumulation of new SuS cases reported in the last 10 years and improved diagnostic tools, we here aimed at updating the demographic and clinical features of SuS and to review the updated ancillary tests being used for SuS diagnosis. Therefore, based on the 2016 criteria, we systematically collected and evaluated data on SuS published from January 2013 to March 2022.

[Susac's syndrome: a rare autoimmune angiopathy in a 71-year-old patient]. / Syndroom van Susac.

BACKGROUND: Susac's syndrome is an autoimmune angiopathy classically leading to the triad of encephalopathy, retinopathy and hearing loss. Multidisciplinarity is essential for diagnosis, which means in more detail a MRI-cerebrum, fluorescence angiography (FAG) and audiography. Early treatment is key since it is associated with better prognosis and reversibility. CASE DESCRIPTION: This article presents a 71-year-old woman with multiple episodes of separate complaints (aphasia, behavioral changes, amnesia and vertigo with tinnitus). The MRI-cerebrum suspected Susac's syndrome with typical callosal lesions. An abnormal FAG and audiography completed the diagnostic triad of Susac's syndrome. Thereafter, treatment with immunosuppressants was initiated, which resulted in cognitive improvement.

Cognitive outcomes in Susac syndrome: A 2-year neuropsychological follow-up study.

BACKGROUND AND PURPOSE: Susac syndrome (SuS) is a rare, autoimmune, neurological disease characterized by a clinical triad of branch retinal artery occlusion, sensorineural hearing loss and encephalopathy. Neuropsychological functioning in SuS is little researched and the prevalence, nature, and evolution over time of cognitive deficits in SuS remain unclear. This study aimed to better understand the long-term neuropsychological outcomes of patients with SuS. METHODS: Thirteen patients with SuS (mean [SD] age 39.5 [11.1] years) were enrolled at the Ghent University Hospital by their treating neurologist. The cognitive functioning and emotional well-being of each patient was evaluated by means of a thorough neuropsychological test battery at baseline and after 2 years. Follow-up testing after 2 years was performed in 11 patients (mean [SD] age 42.2 [11.5] years). RESULTS: Patients showed normal neuropsychological test results at a group level, both at baseline and follow-up testing. Significant improvements over time were found for information processing speed, verbal recognition, and semantic and phonological fluency. Individual test results showed interindividual variability at baseline, with most impairments being in attention, executive functioning and language, which improved after a 2-year period. In addition, patients reported significantly lower mental and physical well-being, both at baseline and follow-up testing. CONCLUSIONS: Our results suggest that neuropsychological dysfunction in SuS is limited at a group level and improves over time. Nonetheless, individual test results reveal interindividual variability, making cognitive screening essential. Furthermore, a high psycho-emotional burden of the disease was reported, for which screening and follow-up are necessary.

Risk factors for severe hearing loss in Susac syndrome: A national cohort study.

BACKGROUND: Nonreversible hearing loss (HL) is the main sequelae of Susac syndrome (SuS). We aimed to identify risk factors for HL in SuS. METHODS: The CARESS study is a prospective national cohort study that started in December 2011, including all consecutive patients with SuS referred to the French reference center. The CARESS study was designed with a follow-up including fundoscopy, audiometry, and brain magnetic resonance imaging at 1, 3, 6, and 12 months after diagnosis and then annually for 5 years. The primary outcome was the occurrence at last follow-up of severe HL defined as the loss of 70 dB in at least one ear on audiometry or the need for hearing aids. RESULTS: Thirty-six patients (female 66.7%, median age 37.5 [range 24.5-42.5] years) included in the clinical study were analyzed for the primary outcome. Thirty-three patients (91.7%) had cochleovestibular involvement at SuS diagnosis including HL >20 dB in at least one ear in 25 cases. At diagnosis, 32 (88.9%), 11 (30.6%), and 7 (19.4%) patients had received steroids, intravenous immunoglobulin, and/or immunosuppressive (IS) drugs, respectively. After a median follow-up of 51.8 [range 29.2-77.6] months, 19 patients (52.8%) experienced severe HL that occurred a median of 13 [range 1.5-29.5] months after diagnosis. Multivariable analysis showed that the odds of severe HL were lower in patients who received IS drugs at diagnosis (OR 0.15, 95% CI 0.01-1.07, p = 0.058). CONCLUSIONS: Severe HL in SuS is associated with the absence of IS drugs given at diagnosis. Our findings support the systematic use of IS drugs in SuS.

Central intra-lesional iron deposits as a possible novel imaging marker at 7 Tesla MRI in Susac Syndrome - an exploratory study.

BACKGROUND: Susac syndrome (SuS) is a rare autoimmune disease that leads to hearing impairment, visual field deficits, and encephalopathy due to an occlusion of precapillary arterioles in the brain, retina, and inner ear. Given the potentially disastrous outcome and difficulties in distinguishing SuS from its differential diagnoses, such as multiple sclerosis (MS), our exploratory study aimed at identifying potential new SuS-specific neuroimaging markers. METHODS: Seven patients with a definite diagnosis of SuS underwent magnetic resonance imaging (MRI) at 7 Tesla (7T), including T2* weighted and quantitative susceptibility mapping (QSM) sequences. T2 weighted hyperintense lesions were analyzed with regard to number, volume, localization, central vein sign, T1 hypointensity, and focal iron deposits in the center of SuS lesions ("iron dots"). Seven T MRI datasets from the same institute, comprising 75 patients with, among others, MS, served as controls. RESULTS: The "iron dot" sign was present in 71.4% (5/7) of the SuS patients, compared to 0% in our control cohort. Thus, sensitivity was 71.4% and specificity 100%. A central vein sign was only incidentally detected. CONCLUSION: We are the first to demonstrate this type of "iron dot" lesions on highly resolving 7T T2*w and QSM images in vivo as a promising neuroimaging marker of SuS, corroborating previous histopathological ex vivo findings.

Therapeutic plasma exchange in refractory Susac's syndrome: A brief report.

Susac's syndrome (SuS) is an autoimmune endotheliopathy that typically presents with the clinical triad of encephalopathy, hearing loss, and branch retinal artery occlusion. It has a wide range of possible presentations, and its pathogenesis remains uncertain. Fulminant and refractory cases are difficult to treat, and no standard treatment protocol has been established. However, therapeutic plasma exchange (TPE) has been described as an adjunctive therapy in several SuS cases. Herein we present a case of a 63-year-old male with debilitating encephalopathy and recent hearing and vision loss, who responded favorably to TPE. Given this and other published reports of plasma exchange therapy for SuS, treatment protocols should consider TPE in early stages of disease.

Susac syndrome - A review of current knowledge and own experience.

Susac syndrome is a rare connective tissue disorder. The pathology affects the small vessels of the brain, retina, and inner ear, and therefore the main symptoms of the disease include encephalopathy, visual disturbances, and sensorineural hearing loss. The aim of this article is to review the current medical knowledge on Susac syndrome and to present our clinical experience regarding this disease entity. In the paper, we are also presenting a case of a 25-year-old patient who was diagnosed with Susac syndrome on the basis of clinical presentation and additional test results. Susac syndrome should be differentiated from multiple sclerosis and other causes of multifocal brain damage as early diagnosis and treatment play a key role in later prognosis.

Clinical characteristics and treatment approaches in patients with Susac syndrome: a scoping review of cases.

BACKGROUND: Susac syndrome (SuS) is a rare disease characterized by encephalopathy, hearing impairment and visual disturbances. Immunosuppressive treatments are used based on the hypothesis that an autoimmune endotheliopathy drives the disease. However, a solid evidence-based treatment approach is lacking. The aim of this review is to provide an overview of patient characteristics, disease course and treatment patterns related to successful outcome that have been reported in literature since 2013. METHODS: Three reviewers conducted a systematic literature search in February 2022. The primary outcome was treatment used, derived from cases classified as probable or definite SuS, describing successful treatment outcome (i.e. no signs of disease activity for ≥ 1 month). Secondary outcomes were time-to-relapse and follow-up time. Published case reports and case series were included. Various clinical characteristics and treatment(s) were extracted and categorized into different phases of treatment. RESULTS: A total of 810 records was identified. 120 articles met inclusion criteria and 161 cases were extracted. Of these, 151 cases were classified as probable or definite SuS and included in the final analysis. Number of combinations of treatments used per treatment phase were: 6 empirically, 35 after confirmed diagnosis, 43 for maintenance treatment, 22 after relapse, 18 during maintenance post-relapse. Median follow-up time was 12.3 months (0.5; 120) and median time to relapse was 4 months (1; 120). CONCLUSION: This scoping review summarizes treatment approaches in patients with SuS, highlighting variability. International efforts to collect clinical, imaging and treatment data from patients with SuS in registries are needed, in order to provide less biased and long-term follow-up information on treatment response, predictors of relapse and patient outcomes. This may lead to more evidence-based therapeutic approaches.

Susac syndrome: neurological update (clinical features, long-term observational follow-up and management of sixteen patients).

Susac syndrome is a likely autoimmune microangiopathy affecting the brain, retina and inner ear. Due to the rarity of this condition, diagnosis and treatment can be challenging. Diagnosis is based on the presence of the clinical triad of central nervous system dysfunction, branch retinal artery occlusions and sensorineural hearing loss. Typical MRI findings of callosal and peri-callosal lesions may assist in diagnosis. Clinical course can be monophasic, polycyclic or chronic continuous. It is important to look out for red flags to attain an accurate diagnosis and follow a therapeutic algorithm based on severity of the disease and response to treatment. Patients are treated with steroids and immunosuppressive agents with a variable response. Early aggressive treatment especially in severe cases, may help in preventing relapses and morbidity/disability. This study highlights important diagnostic features and proposes a treatment algorithm based on clinical experience from management of 16 patients from 2 neuroscience centres in the UK since 2007, who were followed up over a long period of 3-15 years.

Clinically relevant increases in serum neurofilament light chain and glial fibrillary acidic protein in patients with Susac syndrome.

BACKGROUND AND PURPOSE: Serum levels of neurofilament light chain (sNfL) and glial fibrillary acidic protein (sGFAP) are promising neuro-axonal damage and astrocytic activation biomarkers. Susac syndrome (SS) is an increasingly recognized neurological condition and biomarkers that can help assess and monitor disease evolution are highly needed for the adequate management of these patients. sNfL and sGFAP levels were evaluated in patients with SS and their clinical relevance in the relapse and remission phase of the disease was assessed. METHODS: As part of a multicentre study that enrolled patients diagnosed with SS from six international centres, sNfL and sGFAP levels were assessed in 22 SS patients (nine during a relapse and 13 in remission) and 59 age- and sex-matched healthy controls using SimoaTM assay Neurology 2-Plex B Kit. RESULTS: Serum NfL levels were higher than those of healthy controls (p < 0.001) in SS patients and in both subgroups of patients in relapse and in remission (p < 0.001 for both), with significantly higher levels in relapse than in remission (p = 0.008). sNfL levels showed a negative correlation with time from the last relapse (r = -0.663; p = 0.001). sGFAP levels were slightly higher in the whole group of patients than in healthy controls (p = 0.046) and were more pronounced in relapse than in remission (p = 0.013). CONCLUSION: In SS patients, both sNFL and sGFAP levels increased compared with healthy controls. Both biomarkers had higher levels during clinical relapse and much lower levels in remission. sNFL was shown to be time sensitive to clinical changes and can be useful to monitor neuro-axonal damage in SS.

Fluorescein Angiography Findings in Susac Syndrome: A Multicenter Retrospective Case Series.

BACKGROUND: Susac syndrome is a vasculopathy, resulting in the classic triad of branch retinal artery occlusion (BRAO), inner ear ischemia, and brain ischemia. In this retrospective chart review, we characterize fluorescein angiography (FA) findings and other ancillary studies in Susac syndrome, including the appearance of persistent disease activity and the occurrence of new subclinical disease on FA. METHODS: This multicenter, retrospective case series was institutional review board-approved and included patients with the complete triad of Susac syndrome evaluated with FA, contrasted MRI of the brain, and audiometry from 2010 to 2020. The medical records were reviewed for these ancillary tests, along with demographics, symptoms, visual acuity, visual field defects, and findings on fundoscopy. Clinical relapse was defined as any objective evidence of disease activity during the follow-up period after initial induction of clinical quiescence. The main outcome measure was the sensitivity of ancillary testing, including FA, MRI, and audiometry, to detect relapse. RESULTS: Twenty of the 31 (64%) patients had the complete triad of brain, retinal, and vestibulocochlear involvement from Susac syndrome and were included. Median age at diagnosis was 43.5 years (range 21-63), and 14 (70%) were women. Hearing loss occurred in 20 (100%), encephalopathy in 13 (65%), vertigo in 15 (75%), and headaches in 19 (95%) throughout the course of follow-up. Median visual acuity at both onset and final visit was 20/20 in both eyes. Seventeen (85%) had BRAO at baseline, and 10 (50%) experienced subsequent BRAO during follow-up. FA revealed nonspecific leakage from previous arteriolar damage in 20 (100%), including in patients who were otherwise in remission. Of the 11 episodes of disease activity in which all testing modalities were performed, visual field testing/fundoscopy was abnormal in 4 (36.4%), MRI brain in 2 (18.2%), audiogram in 8 (72.7%), and FA in 9 (81.8%). CONCLUSIONS: New leakage on FA is the most sensitive marker of active disease. Persistent leakage represents previous damage, whereas new areas of leakage suggest ongoing disease activity that requires consideration of modifying immunosuppressive therapy.

Effects of a Small-Molecule Perforin Inhibitor in a Mouse Model of CD8 T Cell-Mediated Neuroinflammation.

BACKGROUND AND OBJECTIVES: Alteration of the blood-brain barrier (BBB) at the interface between blood and CNS parenchyma is prominent in most neuroinflammatory diseases. In several neurologic diseases, including cerebral malaria and Susac syndrome, a CD8 T cell-mediated targeting of endothelial cells of the BBB (BBB-ECs) has been implicated in pathogenesis. METHODS: In this study, we used an experimental mouse model to evaluate the ability of a small-molecule perforin inhibitor to prevent neuroinflammation resulting from cytotoxic CD8 T cell-mediated damage of BBB-ECs. RESULTS: Using an in vitro coculture system, we first identified perforin as an essential molecule for killing of BBB-ECs by CD8 T cells. We then found that short-term pharmacologic inhibition of perforin commencing after disease onset restored motor function and inhibited the neuropathology. Perforin inhibition resulted in preserved BBB-EC viability, maintenance of the BBB, and reduced CD8 T-cell accumulation in the brain and retina. DISCUSSION: Therefore, perforin-dependent cytotoxicity plays a key role in the death of BBB-ECs inflicted by autoreactive CD8 T cells in a preclinical model and potentially represents a therapeutic target for CD8 T cell-mediated neuroinflammatory diseases, such as cerebral malaria and Susac syndrome.

Use of disease assessment tools to increase the value of case reports on Susac syndrome: two case reports.

BACKGROUND: Susac syndrome is an immune-mediated, ischemia-producing, occlusive microvascular endotheliopathy that threatens the brain, retina, and inner ear. There is a need for disease assessment tools that can help clinicians and patients to more easily, accurately, and uniformly track the clinical course and outcome of Susac syndrome. Ideally, such tools should simultaneously facilitate the clinical care and study of Susac syndrome and improve the value of future case reports. To meet this need, two novel clinical assessment tools were developed: the Susac Symptoms Form and the Susac Disease Damage Score. The former is a comprehensive self-report form that is completed by patients/families to serially document the clinical status of a patient. The latter documents the extent of damage perceived by individual patients/families and their physicians. Both forms were initially trialed with two particularly representative and instructive patients. The results of this trial are shared in this report. CASE PRESENTATION: Patient 1 is a 21-year-old Caucasian female who presented with an acute onset of headache, paresthesias, cognitive dysfunction, and emotional lability. Patient 2 is a 14-year-old Caucasian female who presented with an acute onset of headache, cognitive dysfunction, urinary incontinence, ataxia, and personality change. Both patients fulfilled criteria for a definite diagnosis of Susac syndrome: both eventually developed brain, retinal, and inner ear involvement, and both had typical "snowball lesions" on magnetic resonance imaging. The Susac Symptoms Form documented initial improvement in both patients, was sufficiently sensitive in detecting a subsequent relapse in the second patient, and succinctly documented the long-term clinical course in both patients. The Disease Damage Score documented minimal disease damage in the first patient and more significant damage in the second. CONCLUSIONS: The Susac Symptoms Form and the Disease Damage Score are useful disease assessment tools, both for clinical care and research purposes. Their use could enhance the value of future case reports on Susac syndrome and could improve opportunities to learn from a series of such reports.

Susac syndrome following COVID-19 vaccination: a case-based review.

COVID-19 vaccine circulation approval was a turning point for the coronavirus pandemic. The current approved COVID-19 vaccines, including messenger ribonucleic acid (mRNA)-based and adenovirus vector-based vaccines, were shown to significantly reduce the disease mortality and severity, and its adverse reactions are mainly mild ones. However, few cases of autoimmune conditions, both flare-ups and new-onset, were described in association with these vaccines. Susac vasculitis (SaS) is a rare autoimmune disease characterized by the clinical triad of encephalopathy, visual disturbances, and sensorineural hearing loss. Its pathogenesis is still not fully understood but is believed to be related to autoimmune processes, including autoantibodies to anti-endothelial cells and cellular immune processes that lead to microvascular damage and, consequently, micro-occlusions of the cerebral, inner ear, and retinal vessels. It has been previously described following vaccination and, most recently, few cases following coronavirus vaccines. We here describe a case of a previously healthy 49-year-old man diagnosed with SaS 5 days following the first dose of the BNT162b2 COVID-19 vaccine.