Clinical, paraclinical and serological findings in Susac syndrome: an international multicenter study

Vision Loss in an Infantryman With Complex Hearing Loss: Case Report and Review of Susac Syndrome

Susac syndrome can resemble various disorders resulting in a delayed or missed diagnosis and subsequent delays in treatment. Here, we present how successful consideration of patient history, symptoms, and ancillary testing led to prompt diagnosis and treatment of Susac syndrome by ophthalmologists. A 27-year-old active duty infantryman presented with sudden vision loss in the right eye during strenuous exercise after experiencing similar symptoms in the left eye 5 months earlier. The patient's medical history was notable for mixed conductive and sensorineural hearing loss, confounded by a history of concussions, syncope, frequent ear infections, tympanic membrane perforation requiring tympanoplasty, and loud noise exposures. Identification of branch retinal artery occlusions on fluorescein angiography and low-to-mid frequency hearing loss confirmed the diagnosis of Susac syndrome. The patient was immediately treated with high-dose oral prednisone and subsequently transitioned to rituximab infusions to preserve vision. Susac syndrome should be considered when a patient presents with vision loss, hearing deficits, and or cognitive changes, even if symptoms are separated by time and seemingly attributed to more common causes.

Susac Syndrome with Classical Triad: A Case Report and Literature Review

Susac syndrome is a rare microangiopathy affecting the brain, retina, and cochlea. Individuals affected typically present with a classical clinical triad of branch retinal artery occlusion (BRAO), encephalopathy or white matter lesions, and sensorineural hearing loss. Herein, we report an exceedingly rare case of a middle-aged female patient with multiple presentations related to her visual field complaints. The presence of multiple bilateral BRAOs, in addition to sensorineural hearing impairment and white matter lesions on the brain magnetic resonance imaging, led to the diagnosis of Susac syndrome. Cases of Susac syndrome are few and far between and have seldom been reported in detail. Awareness of this rare presentation by clinicians and radiologists is of utmost importance to aid in correctly diagnosing and treating such patients.

The neurocognitive and neuropsychiatric manifestations of Susac syndrome: a brief review of the literature and future directions

Encephalopathy is part of the clinical triad of Susac syndrome, but a detailed understanding of the neurocognitive and neuropsychiatric profile of this condition is lacking. Existing literature indicates that cognitive deficits range in severity from subtle to profound. Executive function and short-term recall are affected frequently. Psychiatric manifestations may be absent or may include anxiety, mood disorders or psychosis. If psychiatric phenomena develop during the disease course, it can be hard to disentangle whether symptoms directly relate to the pathology of Susac syndrome or are secondary to treatment-related side effects. In this article, we review what is known about the cognitive and psychiatric morbidity of Susac syndrome and identify areas where knowledge is deficient. Importantly, we also provide a framework for future research, arguing that better phenotyping, understanding of pathophysiology, evaluation of treatments on cognitive and psychiatric outcomes, and longitudinal data capture are vital to improving patient outcomes.

Diagnostic MRI Score to Differentiate Susac Syndrome from Primary Angiitis of the Central Nervous System and Multiple Sclerosis

OBJECTIVE

Susac syndrome (SuS), multiple sclerosis (MS), and primary angiitis of the central nervous system (PACNS) present diagnostic challenges due to overlapping clinical features. We aimed to enhance diagnostic precision by developing the SPAMS (SuS, PACNS, MS) score, a practical radiological tool.

METHODS

This multicenter study included 99 patients (43 SuS, 37 MS, 19 PACNS) from South American countries. Relevant MRI features were identified through an elastic-net model determined key variables.

RESULTS

The SPAMS score assigned 2 points for snowball lesions, 1 point for spokes-like lesions, or if there are more than 4 lesions in the corpus callosum, corpus callosum involvement, or cerebellar involvement. It subtracted 1 point if gadolinium-enhancing lesions or 4 points if Dawson's fingers are present. Bootstrapping validated the optimal cutoff at 2 points, exhibiting a diagnostic performance of area under the curve = 0.931, sensitivity = 88%, specificity = 89%, positive predictive value = 88%, negative predictive value = 89%, and accuracy = 88%.

INTERPRETATION

When specific MRI findings coexisted, the SPAMS score differentiated SuS from MS and PACNS. Access to MRI and standard protocol sequences makes it a valuable tool for timely diagnosis and treatment, potentially preventing disability progression and severe clinical outcomes. ANN NEUROL 2024;96:846-854.

Long-term cognitive outcomes in Susac syndrome: A case series

Susac syndrome (SuS) presents with encephalopathy, visual disturbances, and hearing loss from immune-mediated microvascular occlusion. While acute SuS is well-described, long-term cognitive outcomes with current treatments are underknown. We assessed ten SuS patients treated in accordance with evidence-based guidelines using immunotherapies targeting humoral and cell-mediated pathways. Patients were followed for a median 3.6 years. Initially, cognition inversely correlated with corpus callosum lesions on MRI. All reported cognitive improvement; 5/10 patients had residual deficits in visual attention and executive function. Early, aggressive treatment was associated with good outcomes; extensive early corpus callosum lesions may identify patients at-risk of persistent cognitive deficits.

Uncommon and Miscellaneous Inflammatory Disorders of the Brain and Spine

Inflammatory disorders of the brain and spine have a highly variable MRI appearance, often demonstrating significant overlap in imaging features. The resulting diagnostic dilemma is particularly challenging when considering the more uncommon neuroinflammatory entities. Diligent examination of the salient clinical presentation and signal alteration on imaging examination is necessary when considering neuroinflammation as a diagnostic possibility and may aid in raising suspicion for a particular neuroinflammatory entity. This article reviews a selection of uncommon and miscellaneous inflammatory disorders of the brain and spine to raise awareness of the clinical and imaging features that may assist in this challenging diagnostic task.

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.

Case report: Susac syndrome-two ends of the spectrum, single center case reports and review of the literature

Susac syndrome is a rare and enigmatic complex neurological disorder primarily affecting small blood vessels in the brain, retina, and inner ear. Diagnosing Susac syndrome may be extremely challenging not only due to its rarity, but also due to the variability of its clinical presentation. This paper describes two vastly different cases-one with mild symptoms and good response to therapy, the other with severe, complicated course, relapses and long-term sequelae despite multiple therapeutic interventions. Building upon the available guidelines, we highlight the utility of black blood MRI in this disease and provide a comprehensive review of available clinical experience in clinical presentation, diagnosis and therapy of this disease. Despite its rarity, the awareness of Susac syndrome may be of uttermost importance since it ultimately is a treatable condition. If diagnosed in a timely manner, early intervention can substantially improve the outcomes of our patients.

Diffuse Cerebral Edema With Uncal Herniation Leading to Brain Death in Patient With Fulminant Susac syndrome: Rare Complication of Rare Disease

Susac Syndrome was first described as an inflammatory microangiopathy of the brain and retina. Since then, multiple articles have been published in attempts to improve the understanding of this rare disease. Clinically Susac Syndrome is known to present with triad of encephalopathy, sensorineural hearing loss and branch of retinal artery occlusion (BRAO), along with characteristic "snowball" or "spoke" appearing white matter lesions of the corpus callosum. It has been characterized by vast heterogeneity in terms of its presenting symptoms, severity, and clinical course. Although subset of patients present with severe forms of Susac Syndrome and can develop prominent residual neurologic deficits, it has been reported to be mostly non-life-threatening and only few fatal cases have been described in the literature. Based on the available case reports with fatal outcome, mortality has been related to the systemic complications either during acute disease flare or during chronic-progressive phase. We describe a case of fulminant Susac Syndrome complicated by the sudden and rapid progression of diffuse cerebral edema leading to brain herniation and ultimate brain death, in order to increase awareness of this rare and catastrophic complication.

Clinical Reasoning: A 24-Year-Old Pregnant Woman With Headache and Behavioral Change Progressing to Coma

The broad differential diagnosis associated with progressive subacute encephalopathy can be intimidating, especially in a young, pregnant woman. In this case, a 24-year-old woman at 21 weeks of gestation presented with persistent, drug-resistant fronto-parietal headache, with subsequent progressive development of psychomotor lentification and inappropriate behavior. Physical examination was normal, as were routine laboratory parameters and CT findings, and these symptoms were initially interpreted in the context of chronic depression. Later, the patient developed generalized dystonia and fever, with rapid clinical deterioration, depression of consciousness and, eventually, progression to coma. This case emphasizes the complexity and challenges involved in the diagnostic approach to a patient with progressive subacute encephalopathy framed by worsening CNS symptoms. It highlights the clinical considerations and complementary investigation of various etiologies, in a step-by-step approach, ultimately leading to the final diagnosis. Early recognition and appropriate treatment of these conditions can lead to more favorable outcomes, particularly in gestating patients, where prompt intervention is crucial, and where critical decisions may have to be made regarding pregnancy and the safety of treatment options.

Atypical clinical and novel radiological findings in Susac syndrome: Experience from a large monocentric cohort

Susac syndrome (SuS) is a rare immune-mediated endotheliopathy that affects the brain, retina and inner ear and is characterised by the variable clinical triad of encephalopathy, visual and vestibulocochlear dysfunction. Here, we present clinical and paraclinical data of 19 SuS patients followed at Ghent University Hospital and highlight some atypical clinical and novel radiological findings. Our findings suggest that spinal involvement expands the clinical phenotype of SuS. We further introduce dark blood sequences as a more sensitive technique to detect radiological disease activity in SuS. Our data add to the current understanding of the diagnosis, monitoring and treatment of SuS.

Misdiagnosis of Susac syndrome as demyelinating disease and primary angiitis of the central nervous system: A case report

Susac syndrome (SuS) is a rare neuroinflammatory disease that manifests with a triad of hearing loss, branch retinal artery occlusions, and encephalopathy. Patients with SuS are frequently misdiagnosed because the clinical trial is incompletely present at disease onset. In this report, we present a case of a 29-year-old man manifesting sleepiness, epilepsy, urinary dysfunction, and hemiparesis at the initial stage. Magnetic resonance imaging (MRI) revealed multiple abnormal signals located in the lateral paraventricular, corpus callosal, and pons. In addition, the patient had sustained elevation of CSF pressure and protein. ADEM was considered according to the clinical and radiographic findings. However, symptoms were not significantly improved after methylprednisolone therapy. He showed a vision decline in the third month after the disease onset. It was considered from intracranial hypertension or optic neuritis, and therefore retinal arteriolar impairment was ignored. As the disease progresses, cognitive decline was presented. Brain MRI exhibits multiple significant hyperintensities on the DWI sequence with speck-like gadolinium enhancement. Thus, PACNS was diagnosed. The SuS was not made until the presence of hearing decline in the 4 months after the disease onset. The case will be helpful for clinicians to better recognize the atypical initial manifestation of SuS.

Susac Syndrome: Description of a Single-Centre Case Series

This study describes the clinical characteristics, diagnostic results, treatment regimens, and clinical course of a cohort of patients with Susac syndrome (SS). It is a retrospective observational study of all patients with the diagnosis of SS evaluated at the Hospital Clinic (Barcelona, Spain) between March 2006 and November 2020. Nine patients were diagnosed with SS. The median time from the onset of the symptoms to diagnosis was five months (IQR 9.0), and the median follow-up time was 44 months (IQR 63.5). There was no clear predominance of sex, and mean age of symptoms onset was 36 years (range 19–59). Six patients (67%) presented with incomplete classical clinical triad, but this eventually developed in six patients during the disease course. Encephalopathy, focal neurological signs, visual disturbances, and hearing loss were the most frequent manifestations. Brain magnetic resonance imaging showed callosal lesions in all patients. Most were in remission within two years. Only four patients met the proposed criteria for definite SS. When SS is suspected, a detailed diagnostic workup should be performed and repeated over time to identify the clinical manifestations that will lead to a definite diagnosis.

Incomplete Susac’s Syndrome: A Case Report and Literature Review

Susac syndrome (SS) is rare microangiopathy of unclear etiology involving arteries of the brain, cochlea, and retina, affecting mainly middle-aged women. The diagnosis of Susac syndrome is based on a clinical evaluation of the signs and symptoms supported by imaging modalities. Immunosuppressants are the first-line treatment. Our patient is a 46-year-old man who was evaluated for right-sided visual loss and bilateral hearing loss. His ophthalmic examination revealed retinal artery occlusion. He showed a good response to rituximab and his vision remained stable. Our case is particularly unique as it shows an incomplete Susac syndrome involving the cochlea and retina only. This paper aims to increase awareness about the disease's symptoms, treatment, and prognosis. 

Susac Syndrome: A Case Series

BACKGROUND

Susac syndrome (SS) is an autoimmune disorder that involves the eyes, the brain, and the ears. It is a rare cause of recurrent branch retinal artery occlusion. The purpose of this study was to report cases of SS, highlighting the clinical presentations, therapeutic options, and their outcome.

PATIENTS AND METHODS

Retrospective case series of patients seen at our institution for SS between 2005 and 2020. Demographics, clinical characteristics, treatment, and outcome were studied.

RESULTS

Four patients (3 females, mean age 29 years old) were included in the study. According to the recently revised diagnostic criteria, three patients had definite and one patient had probable SS (distinctive ophthalmological and brain involvement without ear involvement). Initial visual acuity (VA) was normal in all eyes, but two patients had unilateral visual field impairment. Gass plaques (defined as yellow-white plaques found in the arteriolar wall away from arterial bifurcations) were observed on fundus examination in all patients. Fluorescein angiography revealed arteriolar wall hyperfluorescence and branch retinal arterial occlusions (BRAOs) in the absence of other signs of intraocular inflammation in all patients. Initial treatment consisted of a high-dose corticosteroid (intravenous or oral) with additional immunosuppressive therapy (azathioprine, intravenous immunoglobulins, mycophenolate mofetil, and/or cyclophosphamide). Residual symptoms were present in all patients and included scotoma (n = 2) and hearing loss (n = 3).

CONCLUSION

SS is a rare disease with characteristic ophthalmological manifestation. The majority of patients present a crude form of the triad, and retinal findings may be the first initial manifestation. Ophthalmologists should consider the possibility of an SS in all young patients presenting with BRAOs.

Involuntary crying episodes with Susac's syndrome-a rare presentation of a rare disease: a case report

BACKGROUND

In this case, we reported the pseudobulbar affect (PBA) in a patient with Susac's syndrome-a rare condition that was caused by a rare syndrome. Previous case reports of Susac syndrome described psychiatric symptoms such as emotional disturbances or personality changes. Only a few case reports have reported psychiatric disorders in patients with Susac's syndrome. There were no reported cases of Susac syndrome with PBA as an initial presentation.

CASE PRESENTATION

Our patient was 56 years old and presented with involuntary crying, left-sided headache, left-sided hearing loss, and tinnitus. Brain MRI showed numerous areas of restricted diffusion and enhancement involving the corpus callosum, bilateral hemispheres, and brainstem. Ophthalmological evaluation showed bilateral branch retinal artery occlusion. She was diagnosed with Susac's syndrome and PBA. She was treated with cyclophosphamide and dextromethorphan hydrobromide/quinidine sulfate with excellent recovery. This is a 2-year clinical course.

DISCUSSION AND CONCLUSIONS

Recognition of the clinical presentation of Susac's syndrome and PBA with early diagnosis and treatment are the keys to preventing further disability and impact on patients and their families.

Susac's syndrome - A new ocular finding and disease outcome

BACKGROUND

Susac's syndrome, a rare autoimmune vasculo-occlusive disease, may pose a diagnostic challenge and result in a devastating ocular and systemic outcome. Our study identifies a new retinal finding and evaluates disease outcome. We aimed to assess clinical and imaging findings, systemic manifestations and disease outcome in patients with ocular Susac's syndrome under immunosuppressive/immunomodulation therapies.

METHODS

Retrospective tertiary center study including patients with a diagnosis of Susac's syndrome with >12 months follow up. Medical record review including ocular, neurological and auditory clinical and imaging findings, and treatment modalities. Main outcome measures were clinical manifestations and disease outcome.

RESULTS

Seven patients (14 eyes) with a mean age of 34.1 years were included. Mean follow-up was 31.9 months (12.4-72.4). All had bilateral ocular disease. Retinal microaneurysms, a new ocular finding, were demonstrated in 5 patients and persisted at the final visit. In 5 eyes, they further extended during follow-up. All were treated with immunosuppressive drugs and 5/7 additional immunomodulation therapy. At last examination, best corrected visual acuity was >20/40 in all eyes, 1/10 eyes had visual field deterioration, no eye had active ocular disease, all patients achieved neurological stability, and 1 patient had auditory deterioration.

CONCLUSION

Retinal microaneurysms, a new ocular finding in Susac's syndrome, were present in most of our patients, indicating ischemic retinal damage. Immunosuppressive and immunomodulation therapies seem to be highly effective in the control of disease activity.

[Unusual forms of inflammatory diseases of the central nervous system]

BACKGROUND

White matter lesions of the central nervous system (CNS) are frequently encountered on magnetic resonance imaging (MRI) exams. If the morphologic findings, clinical symptoms and laboratory results are not typical for one of the more common inflammatory CNS diseases, the diagnosis may become challenging, which also means that interesting and sometime emotional discussions may arise.

OBJECTIVE

While frequent causes of inflammatory CNS diseases were already discussed in a previous article, we now focus on more seldom forms and place attention on morphologic characteristics which may help to find the correct diagnosis.

Diagnosis, differential diagnosis and misdiagnosis of Susac syndrome

Background and purpose

Susac syndrome (SuS) is an inflammatory condition of the brain, eye and ear. Diagnosis can be challenging, and misdiagnosis is common.

Methods

This is a retrospective review of the medical records of 32 adult patients from an Australasian cohort of SuS patients.

Results

An alternative diagnosis prior to SuS was made in 30 patients (94%) with seven patients receiving two or more diagnoses. The median time to diagnosis of SuS was 3 months (range 0.5–100 months). The commonest misdiagnoses were migraine in 10 patients (31%), cerebral vasculitis in six (19%), multiple sclerosis in five (16%) and stroke in five (16%). Twenty‐two patients were treated for alternative diagnoses, 10 of whom had further clinical manifestations prior to SuS diagnosis. At presentation seven patients (22%) met criteria for definite SuS, 19 (59%) for probable SuS and six (19%) for possible SuS. Six patients (19%) presented with brain–eye–ear involvement, 14 with brain–ear (44%), six with brain–eye (19%) and six (19%) with only brain involvement. In patients with the complete triad of symptoms the median delay to diagnosis was 3 months (range 1–9 months) compared to 5.25 months (range 0.5–100 months) for patients with encephalopathy and ocular symptoms at presentation.

Conclusions

Susac syndrome patients are frequently misdiagnosed at initial presentation, despite many having symptoms or radiological features that are red flags for the diagnosis. Delayed diagnosis can lead to patient morbidity. The varied ways in which SuS can present, and clinician failure to consider or recognize SuS, appear to be the main factors leading to misdiagnosis.

Autoimmune Meningitis and Encephalitis

Meningitis and encephalitis are inflammatory syndromes of the meninges and brain parenchyma, respectively, and may be identified either by finding definitive evidence of inflammation on tissue pathology or by cerebrocpinal fluid (CSF) analysis showing pleocytosis or intrathecal antibody synthesis. Clinicians evaluating undifferentiated meningitis or encephalitis should simultaneously consider autoimmune, infectious, and neoplastic causes, using patient risk factors, clinical syndrome, and diagnostic results including CSF and MRI findings to narrow the differential diagnosis. If an autoimmune cause is favored, an important early diagnostic question is whether a specific neural autoantibody is likely to be identified.

LCCL peptide cleavage after noise exposure exacerbates hearing loss and is associated with the monocyte infiltration in the cochlea

Acoustic trauma induces an inflammatory response in the cochlea, resulting in debilitating hearing function. Clinically, amelioration of inflammation substantially prevents noise-induced hearing loss. The Limulus factor C, Cochlin, and Lgl1 (LCCL) peptide plays an important role in innate immunity during bacteria-induced inflammation in the cochlea. We aimed to investigate the LCCL-induced innate immune response to noise exposure and its impact on hearing function.

METHODS

We used Coch (encodes cochlin harboring LCCL peptide) knock-out and p.G88E knock-in mice to compare the immune responses before and after noise exposure. We explored their hearing function and hair cell degeneration. Moreover, we investigated distinct characteristics of immune responses upon noise exposure using flow cytometry and RNA sequencing.

RESULTS

One day after noise exposure, the LCCL peptide cleaved from cochlin increased over time in the perilymph space. Both Coch^-/- and Coch^G88E/G88E mutant mice revealed more preserved hearing following acoustic trauma compared to wild-type mice. The outer hair cells were more preserved in Coch^-/- than in wild-type mice upon noise exposure. The RNA sequencing data demonstrated significantly upregulated cell migration gene ontology in wild-type mice than in Coch^-/- mice following noise exposure, indicating that the infiltration of immune cells was dependent on cochlin. Notably, infiltrated monocytes from blood (C11b⁺/Ly6G^-/Ly6C⁺) were remarkably higher in wild-type mice than in Coch^-/- mice at 1 day after noise exposure.

CONCLUSIONS

Noise-induced hearing loss was attributed to over-stimulated cochlin, and led to the cleavage and secretion of LCCL peptide in the cochlea. The LCCL peptide recruited more monocytes from the blood vessels upon noise stimulation, thus highlighting a novel therapeutic target for noise-induced hearing loss.

Successful Treatment of Incomplete Susac Syndrome with Simultaneous Corticosteroids and Plasmapheresis Followed by Rituximab

We present a case report of a patient with incomplete Susac syndrome. He had cognitive impairment, corpus callosum lesions, and vestibulocochlear dysfunction on brainstem auditory evoked responses. He was treated with methylprednisolone and plasmapheresis, improved, and then, also received rituximab. His improvement has been lasting as of this writing. This case shares our experience with a successful treatment of this rare condition that is incompletely understood and lacks well-established treatment guidelines.

RECURRENT BRANCH RETINAL ARTERY OCCLUSION FROM SUSAC SYNDROME: CASE REPORT AND REVIEW OF LITERATURE

PURPOSE

We report a patient with branch retinal artery occlusion predominant Susac syndrome and review the literature on current diagnostic modalities and therapeutic approaches for this rare condition.

METHODS

Case report.

RESULTS

A 23-year-old white male presented with a 5-month history of a scotoma in his right eye vision, headaches, and intermittent paresthesias of the lower extremities. Ophthalmic examination was normal with the exception of a hypopigmented small retinal area inferonasal to the fovea in the right eye. Optical coherence tomography demonstrated inner retinal atrophy and optical coherence tomography angiography showed deep capillary layer vessel dropout in both eyes. Ultra-wide-field fluorescein angiography revealed bilateral arteriolar wall hyperfluorescence. Corpus callosal lesions were present on magnetic resonance imaging. Lumbar puncture demonstrated elevated protein. Audiogram was normal. A diagnosis of Susac syndrome was made. The patient initially received oral steroids followed by intravenous steroids and mycophenolate mofetil because of new branch retinal artery occlusions. Thirteen months after initial presentation, the vision was stable at 20/20 in both eyes.

CONCLUSION

It is a diagnostic challenge when recurrent branch retinal artery occlusion secondary to Susac syndrome presents without the classic symptoms. Optical coherence tomography angiography and subtle magnetic resonance imaging findings aided in early recognition of the diagnosis in our patient. Ultra-wide-field fluorescein angiography was an important tool in disease monitoring. Aggressive management with intravenous corticosteroids and initiation of immunosuppression resulted in long-term preservation of vision and improvement in visual field.

Fundamental mechanistic insights from rare but paradigmatic neuroimmunological diseases

The pathophysiology of complex neuroimmunological diseases, such as multiple sclerosis and autoimmune encephalitis, remains puzzling - various mechanisms that are difficult to dissect seem to contribute, hampering the understanding of the processes involved. Some rare neuroimmunological diseases are easier to study because their presentation and pathogenesis are more homogeneous. The investigation of these diseases can provide fundamental insights into neuroimmunological pathomechanisms that can in turn be applied to more complex diseases. In this Review, we summarize key mechanistic insights into three such rare but paradigmatic neuroimmunological diseases - Susac syndrome, Rasmussen encephalitis and narcolepsy type 1 - and consider the implications of these insights for the study of other neuroimmunological diseases. In these diseases, the combination of findings in humans, different modalities of investigation and animal models has enabled the triangulation of evidence to validate and consolidate the pathomechanistic features and to develop diagnostic and therapeutic strategies; this approach has provided insights that are directly relevant to other neuroimmunological diseases and applicable in other contexts. We also outline how next-generation technologies and refined animal models can further improve our understanding of pathomechanisms, including cell-specific and antigen-specific CNS immune responses, thereby paving the way for the development of targeted therapeutic approaches.

Susac's Syndrome: An Updated Review

Susac's syndrome is a rare immune-mediated endotheliopathy that mainly affects young women. It is characterised by the presence of encephalopathy, retinal vaso-occlusive disease and hearing loss. Diagnosis is based on the clinical presentation, brain magnetic resonance imaging, retinal fluorescein angiography, and audiometry. Treatment consists of immunosuppressive therapy. This review focuses on recent developments in the diagnosis and management of the condition.

Susac Syndrome and Pregnancy

Susac syndrome (SuS) is a rare poorly characterised disorder that affects the brain, retina, and cochlea. Here, we present a case of a 31-year-old pregnant female with a new diagnosis of SuS that was successfully managed to 36 weeks of gestation with minimal disease burden to both the mother and newborn. She was treated initially using intravenous methylprednisolone followed by oral prednisone, and intravenous immunoglobulin (IVIg). We stress the importance of a multidisciplinary approach, involving both neurology and maternal-fetal medicine, and provide guidance in navigating the various options for immunosuppressive therapy during pregnancy.

Neuro-ophthalmic manifestations of Susac syndrome

PURPOSE OF REVIEW

This review discusses general features and organ-specific presentations of Susac syndrome as well as diagnosis and treatment.

RECENT FINDINGS

Latest literature regarding demographics, new diagnostic modalities such as optical coherence tomography and treatment options for Susac syndrome are discussed in detail in this review, summarizing the most recent updated information.

SUMMARY

Susac syndrome is a rare, underdiagnosed, and often misdiagnosed disease that can lead to severe complications such as deafness, vision loss, dementia, and death. It involves the central nervous system and may mimic other neurological and neuro-ophthalmological diseases.

Susac syndrome (Retino-cochleo-cerebral vasculitis), the ophthalmologist in the role of the whistleblower

BACKGROUND/PURPOSE

Susac syndrome is a rare microangiopathy of suspected autoimmune origin affecting arteries of the retina, the cochlea and the brain. The aim of the study was to give a review of the disease entity and determine the proportion of cases and their characteristics in a uveitis referral centre.

PATIENTS AND METHODS

Charts of patients with the diagnosis of Susac syndrome seen in the Uveitis Clinic of the Centre for Ophthalmic Specialised Care (COS), Lausanne, Switzerland were reviewed retrospectively to determine the frequency of such cases in a uveitis referral centre. Clinical symptoms and signs, functional data, imaging signs and evolution were analysed in the 3 COS cases and one case shared with the Uveitis Clinic of the Department of Ophthalmology, University of Innsbruck, Austria. Characteristic signs were searched possibly allowing a prompt diagnosis.

RESULTS

During the period from 1994 to 2019 (24 years, 2045 patients), 3 charts with the diagnosis of Susac syndrome were found (0.15%). The whole collective, including the additional case, comprised three women aged 28, 32 and 63 at presentation and one man, aged 42. None of the 3 cases that were referred were diagnosed beforehand. The characteristic item found in all 4 cases was the abrupt arterial stop or segmental interruption of arteries and increased staining of arterial wall on angiography more clearly shown on indocyanine green angiography that can potentially be proposed as a crucial diagnostic element. All 4 cases responded to dual steroidal and non-steroidal immunosuppression. Under treatment, all four patients did not show any further evolution.

CONCLUSION

Susac syndrome is a multilocation arteritis of the head that can involve the eye, ear and brain often first diagnosed by the ophthalmologist. The diagnosis is rapidly reached in uveitis referral centres but seems to be missed otherwise, A helpful angiographic sign to be searched is an abrupt or segmental arterial stop and increased staining of the arterial wall more clearly seen on indocyanine green angiography. Patients often present first to the ophthalmologist who should be acting as a whistleblower to avoid severe involvement of the brain.

Increased incidence of Susac syndrome: a case series study

BACKGROUND

Susac syndrome (SuS) is a rare condition characterized by a clinical triad of sensorineural hearing loss, branch artery occlusion and encephalopathy. This study reports an increased incidence of SuS in Israel. We describe the clinical characteristics of these patients, diagnostic procedures and the use and subsequent outcomes of newly published treatment guidelines.

METHODS

This is a single center retrospective study. Patients who were diagnosed with SuS between July 2017 and August 2018 were enrolled in this study.

RESULTS

Seven patients were diagnosed with SuS according to the diagnostic criteria in a time period of 13 months. The annual incidence was recently evaluated in Austria to be 0.024/100000, therefore, our case series represent at least a 5.4- fold increase in the annual incidence of SuS expected in Israel and a 7-fold increase in the annual incidence expected in our medical center. Mean time from the onset of the symptoms to diagnosis was three weeks and follow-up time was twenty four months. Recent exposure to cytomegalovirus was serologically evident in three patients and one patient had high titer of anti-streptolysin antibody. All patients underwent brain MRI, fluorescein angiography and audiometry. All patients were treated according to the newly recommended guidelines. All patients achieved clinical and radiological stability.

CONCLUSIONS

We report of an increased incidence of SuS in Israel. Infectious serological findings may imply a post infectious mechanism. The use of the recommended diagnostic procedures reduced the time to diagnosis. Newly published treatment guidelines led to favorable clinical outcomes.

The Role of Anti-Endothelial Cell Autoantibodies and Immune Response in Acute Low-Tone Hearing Loss

OBJECTIVE

Immunity is associated with acute low tone hearing loss. However, the exact pathophysiology of immunity-mediated acute low tone hearing loss remains unknown. In this study, we evaluated the presence, therapeutic effectiveness, and immunopathological mechanisms of anti-endothelial cell autoantibodies (AECEs) in patients with acute low-frequency hearing loss.

MATERIAL AND METHODS

Forty-nine patients who were treated as inpatients having acute low-frequency hearing loss and additional symptoms, such as ear fullness, tinnitus, dizziness, or hyperacusis, were enrolled in this study. Serum samples from these patients were collected for laboratory serum autoimmunity detection, including AECAs, antinuclear antibodies, immunoglobulin, and circular immune complex. Therapeutic responses to combination therapy in short-term outcome and serum cytokine levels were compared between AECA-positive and AECA-negative patients.

RESULTS

Anti-endothelial cell autoantibodies-positive patients tended to show significantly less response to standard therapy compared with AECAs controls (P < .05). Moreover, some serum cytokine levels elevated in both AECAs- and AECAs+ groups. Positive ratio of interleukin-8 and concentrations of macrophage inflammatory protein-1α were found higher in AECAs+ groups (P < .05).

CONCLUSION

The results supported that AECAs might wield influence on the short-term outcome of acute low-tone hearing loss (ALHL) treatment. Furthermore, AECA-mediated acute low-frequency hearing loss possibly involved dysregulation of inflammation process and release of cytokines.

CNS vasculopathies: Challenging mimickers of primary angiitis of the central nervous system

Primary angiitis of the central nervous system (CNS) is an inflammatory vasculopathy affecting the brain and spinal cord. It is a difficult diagnosis to make because of its insidious nonspecific course and its multiple mimics. This review identifies and discusses some noninfectious mimickers of primary CNS angiitis, including: reversible cerebral vasoconstriction syndrome, Sneddon's Syndrome, amyloid-beta-related angiopathy, Susac Syndrome, and neurosarcoidosis. Each condition will be reviewed in terms of epidemiology, pathology, clinical presentation, diagnostic approach, and treatment. Distinguishing these mimics from the primary angiitis of the CNS is important for proper treatment and prognosis.

Complete Susac syndrome in a 22-year old male in Colombia: Case report and a review of the literature

We report the case of a 22 year-old male with a clinical picture of 4 months onset of headaches, deafness, and a decrease of vision in the left eye. His mother mentioned he also had changes in behaviour and mood. The magnetic resonance scan of the brain showed multiple hyper-intense lesions in the knee of the corpus callosum. The hearing test reported a neurosensory deafness. In the ophthalmoscopy, a retinal infarction was observed in the nerve fibre layer in the left eye, which was confirmed using optical coherence tomography. The fluorescein angiography showed multiple foci of hyperfluorescence of the arteriole walls, arteriole filling defects, and regional ischaemia foci of the choroid. These findings confirmed the presumed diagnosis of a Susac syndrome. This is one of the few cases reported in the literature of a Susac syndrome in a young man with the complete diagnostic triad, and the first in Colombia.

Diagnostic Criteria and Treatment Algorithm for Susac Syndrome

BACKGROUND

Susac syndrome (SS) classically presents with the clinical triad of retinal artery occlusion, sensorineural hearing loss, and encephalopathy and the neuroimaging triad of white matter lesions, deep gray matter lesions, and leptomeningeal disease. However, patients can present with an incomplete clinical or neuroimaging triads making diagnosis difficult in certain situations. A standard treatment paradigm also is lacking in this illness. It is important for neuro-ophthalmologists to recognize clinical and radiographic findings that are pathognomonic for this syndrome and have a basic understanding of the available treatment options.

EVIDENCE ACQUISITION

Review of medical literature.

RESULTS

A definite diagnosis of SS is made when the clinical triad or the neuroimaging triad is present. There are numerous reports of 2 other imaging findings in this condition: arteriolar wall hyperfluorescence (AWH) on fluorescein angiography in retinal arterioles remote from retinal ischemia and central callosal lesions on MRI. Both of these imaging findings are diagnostic of SS. Gass plaques in retinal arterioles are almost always seen in the acute phase of the illness but are not pathognomonic for SS. The most common medications used in this syndrome are corticosteroids and intravenous immunoglobulin. A number of other medications have been used including mycopheolate, rituximab, azathioprine, and cyclophosphamide.

CONCLUSIONS

In the absence of the clinical triad or magnetic resonance imaging triad for SS, AWH remote from retinal vascular injury and central callosal lesions are confirmatory of the diagnosis because they have never been described in any other condition. The presence of Gass plaques in retinal arterioles should strongly suggest the diagnosis. Despite the lack of clinical trial data, patients with SS must be treated promptly and aggressively. In more fulminant cases, addition of mycophenolate mofetil or rituximab is required, followed by cyclophosphamide when disease is refractory to other medications.

Heritable and non-heritable uncommon causes of stroke

Despite intensive investigations, about 30% of stroke cases remains of undetermined origin. After exclusion of common causes of stroke, there is a number of rare heritable and non-heritable conditions, which often remain misdiagnosed, that should be additionally considered in the diagnosis of cryptogenic stroke. The identification of these diseases requires a complex work up including detailed clinical evaluation for the detection of systemic symptoms and signs, an adequate neuroimaging assessment and a careful family history collection. The task becomes more complicated by phenotype heterogeneity since stroke could be the primary or unique manifestation of a syndrome or represent just a manifestation (sometimes minor) of a multisystem disorder. The aim of this review paper is to provide clinicians with an update on clinical and neuroradiological features and a set of practical suggestions for the diagnostic work up and management of these uncommon causes of stroke. The identification of these stroke causes is important to avoid inappropriate and expensive diagnostic tests, to establish appropriate management measures, including presymptomatic testing, genetic counseling, and, if available, therapy. Therefore, physicians should become familiar with these diseases to provide future risk assessment and family counseling.

Next-Generation Neuroimmunology: New Technologies to Understand Central Nervous System Autoimmunity

Understanding neuroimmunological disorders is essential for developing new diagnostic and therapeutic strategies. Rodent models have provided valuable insights, but are sometimes equated with their human counterparts. Here, we summarize how novel technologies may enable an improved human-focused view of immune mechanisms. Recent studies have applied these new technologies to the brain parenchyma, its surrounding cerebrospinal fluid, and peripheral immune compartments. Therapeutic interventions have also facilitated translational understanding in a reverse way. However, with improved technology, access to patient samples remains a rate-limiting step in translational research. We anticipate that next-generation neuroimmunology is likely to integrate, in the immediate future, diverse technical tools for optimal diagnosis, prognosis, and treatment of neuroimmunological disorders.

CD8+ T cell-mediated endotheliopathy is a targetable mechanism of neuro-inflammation in Susac syndrome

Neuroinflammation is often associated with blood-brain-barrier dysfunction, which contributes to neurological tissue damage. Here, we reveal the pathophysiology of Susac syndrome (SuS), an enigmatic neuroinflammatory disease with central nervous system (CNS) endotheliopathy. By investigating immune cells from the blood, cerebrospinal fluid, and CNS of SuS patients, we demonstrate oligoclonal expansion of terminally differentiated activated cytotoxic CD8+ T cells (CTLs). Neuropathological data derived from both SuS patients and a newly-developed transgenic mouse model recapitulating the disease indicate that CTLs adhere to CNS microvessels in distinct areas and polarize granzyme B, which most likely results in the observed endothelial cell injury and microhemorrhages. Blocking T-cell adhesion by anti-α4 integrin-intervention ameliorates the disease in the preclinical model. Similarly, disease severity decreases in four SuS patients treated with natalizumab along with other therapy. Our study identifies CD8+ T-cell-mediated endotheliopathy as a key disease mechanism in SuS and highlights therapeutic opportunities.

Progressive sensorineural hearing loss many years preceding completion of Susac's syndrome triad: A case report

Susac's syndrome (SuS) is a rare disorder with a clinical triad of encephalopathy, sensorineural hearing loss, and branch retinal artery occlusions. We report a 7-year-old girl who presented with chronic, progressive sensorineural hearing loss, who, years later, presented with encephalopathy and vision loss. Such prolonged period between symptoms is unusual and to our knowledge, this is the longest interval between onset of hearing loss and completion of the full triad in SuS. In addition, she had a protracted disease course, requiring multiple immune therapies for disease control.

Novel uses of retinal imaging with optical coherence tomography in multiple sclerosis

Introduction: Multiple Sclerosis (MS) is the most common chronic autoimmune neuroinflammatory condition in young adults. It is often accompanied by optic neuritis (ON) and retinal neuro-axonal damage causing visual disturbances. Optical coherence tomography (OCT) is a sensitive non-invasive method for quantifying intraretinal layer volumes. Recently, OCT not only showed to be a reliable marker for ON-associated damage, but also proved its high prognostic value for functional outcome and disability accrual in patients with MS. Consequently, OCT is discussed as a potential marker for monitoring disease severity and therapeutic response in individual patients. Areas covered: This article summarizes our current understanding of structural retinal changes in MS and describes the future potential of OCT for differential diagnosis, monitoring of the disease course and for clinical trials. Expert commentary: Today, OCT is used in clinical practice in specialized MS centers. Standardized parameters across devices are urgently needed for supporting clinical utility. Novel parameters are desirable to increase sensitivity and specificity in terms of MS.