Do Not Forget Susac Syndrome in Patients with Unexplained Acute Confusion

Sudden onset hearing loss as initial presentation of Susac syndrome: a rare case report and brief review

Susac syndrome is a rare disease presenting with a classic triad of symptoms. These are sensorineural hearing loss, encephalopathy, and branch retinal artery occlusions. Initial presentation is usually headache and symptoms of encephalopathy. Hearing loss is unusual in the early stages but, when it does present, can often lead to a misdiagnosis of sudden sensorineural hearing loss. Hence, neurological and retinal examinations are essential to an accurate diagnosis. In this study, we aimed to raise awareness of Susac syndrome among physicians and facilitate recognition of its manifestation, especially in those patients presenting with hearing loss alone. Identifying Susac syndrome that presents as sudden sensorineural hearing loss can be challenging but a number of case reviews have been reported in recent years and treatment guidelines are available.

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.

Neuropsychological characteristics of encephalopathy in Susac's Syndrome - Case report

Susac's Syndrome (SS) is a rare, autoimmune angiopathy characterized by hearing loss, retinal artery occlusions and encephalopathy, which is usually expressed in multifocal neurological signs and symptoms, confusion state and cognitive impairment. There have been few descriptions of neuropsychological assessment of SS. We present a case study of 29-year-old woman who developed full SS. During the post-acute stage of disease, she was admitted to neurorehabilitation ward to improve her cognitive-behavioral and motor functioning. The initial assessment revealed attention, memory and executive dysfunctions, as well as behavioral changes including impulsivity, affective dysregulation and reduced self-awareness of disease deficits. After five weeks recovery process supported by rehabilitation program, improvement was observed, although some cognitive-behavioral deficits were still present in the follow-up assessment.

Potential benefits of early aggressive immunotherapy in Susac syndrome

Susac syndrome is a rare vasculopathy of unknown aetiology, affecting prominently young women and electively targeting brain (encephalopathy), retina (visual field defects), and cochlea (hearing loss), of which optimal treatment has yet to be established. We report clinical, CSF and MRI features together with the long-term outcome in a monocentric series of eight consecutive patients with unusual sex ratio (5 male; 3 female), to define the best diagnostic/therapeutic strategy. Six patients presented with the classical clinical triad within less than 6 months after symptoms onset; two did not suffer from sensorineural hearing loss. All but one received a treatment combining high doses of methylprednisolone and cyclophosphamide intravenously. The first two patients had very delayed diagnosis (6-4 months) resulting in severe cognitive sequelae. The third one had only mildly delayed diagnosis (2 months) with subsequent behaviour impairment and severe right hypoacousia. All three were unable to return to work. The last five patients who had early diagnosis and undelayed aggressive treatment were able to resume their professional activities.