Susac syndrome (SS) is a rare disorder characterized by the following triad: central nervous system (CNS) dysfunction , retinal arterial branch occlusions (BRAO), and sensorineural hearing loss (SNHL). It is presumably due to microvessel occlusions in the CNS, retina, and inner ear from autoimmune causes.
Summary
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- 1 Synonyms
- 2 Prevalence
- 3 Inheritance
- 4 Age of onset or onset
- 5 Epidemiology
- 6 Clinical description
- 7 Etiology
- 8 Diagnostic methods
- 1 Differential diagnosis
- 9 Management and treatment
- 10 Forecast
- 11 Sources
Synonyms
- Small infarcts of cochlear, retinal and brain tissue
- RED-M
- Retinopathy, encephalopathy, deafness associated with microangiopathy
- SICRET syndrome
- Retino-cochlear-cerebral vascular disease
Prevalence
- Unknown
Heritage
- Unknown
Age of onset or onset
- Any age
epidemiology
The prevalence of SS is still unknown, but to date more than 300 cases have been reported worldwide. Young women (20 to 40 years old) are the most affected (3.5: 1 ratio).
Clinical description
The age of onset of the disease varies between 8 and 72 years (the average age is 32 years). Clinically, SS consists of the triad encephalopathy and / or focal dysfunction of the CNS, BRAO, and SNHL. However, it is rare to find all three components at the same time in the initial presentation of the disease. Often, SS is preceded by headache (migraine or constant). The encephalopathy is characterized by loss of memory , confusion , disorientation, behavioral disorders, personality changes and psychosis . Focal CNS signs include ataxia, motor and sensory deficiencies, dysarthria and oculomotor dysfunction. Optical involvement includes scotoma and visual distortion. BRAO can also occur in the periphery and not cause clinical deficits. Hearing loss , usually in the low to mid frequencies, may be associated with boisterous tinnitus and vertigo . Occasionally myalgias and / or arthralgias as well as urinary dysfunction can be observed . Based on clinical evolution, a classification into three main forms has been suggested: monocyclic (fluctuating disease that self-limits after a maximum period of 2 years and does not recur), polycyclic (relapses that continue for a period of more than 2 years) and chronic-continuous.
Etiology
Its etiology is unknown, although it is believed to be an autoimmune process that causes inflammation and occlusion of the precapillary arterioles of the brain , retina, and inner ear .
Diagnostic methods
The diagnosis of SS includes nuclear magnetic resonance imaging studies that show characteristic lesions confined to the central fibers of the corpus callosum (snowball-like lesions). Periventricular lesions and involvement of the cerebellum , brain stem, and deep gray matter nuclei are often seen . Fluorescein retinal angiography results reveal BRAO and fluorescein losses. Audiometric analyzes reveal unilateral or bilateral SNHL. Cerebrospinal fluid analyzes often show mild pleocytosis and moderate protein augmentation, while oligoclonal bands are rare. The impact of autoantibody diagnosis is currently under investigation.
Differential diagnosis
Differential diagnosis includes CNS demyelinating and inflammatory diseases (such as multiple sclerosis , disseminated acute encephalitis , neuromyelitis optica (Devic’s disease)), other CNS diseases (Menière’s disease), infections, neoplasms, psychotic disorders, cerebrovascular disease, and isolated retinal arterial branch occlusion) and autoimmune diseases (limbic encephalitis, Cogan syndrome , Eales disease, autoimmune inner ear disease, polyarteritis nodosa, Wegener’s granulomatosis, Churg-Strauss syndrome , systemic lupus erythematosus, antiphospholipid syndrome , syndrome from Sjögren andBehçet’s disease ).
Management and treatment
There are no evidence-based treatment strategies. Empirical treatment consists of aggressive multimodal immunosuppressive therapy in the acute period, with high doses of corticosteroids, cyclophosphamide, methotrexate, azathioprine and / or mycophenolate mofetil, and intravenous immunoglobulins. After the acute period, treatment is continued with a slow reduction of corticosteroids. Alternative drugs such as rituximab, etanercept or cyclosporine A may be useful in treatment-resistant cases. A cochlear implant may be useful for patients with significant hearing loss. Platelet antiplatelets are empirically recommended.
Forecast
The disease is usually self-limiting and often stabilizes between 2 and 4 years, but often causes cognitive, visual, and hearing deficits. Late relapses and also progressive chronic evolution can occur.
