Case report: Anti septin-5-encephalitis as a treatable cause of cerebellar ataxia and psychiatric symptoms

Abstract

ObjectivesAnti-septin-5 encephalitis is a rare disease with only few published cases, mainly based on retrospective CSF and serum analyses. Predominant symptoms are cerebellar ataxia and oculomotor abnormalities. Due to the rareness of the disease, treatment recommendations are scarce. Herein, we prospectively describe the clinical course of a female patient with anti-septin-5 encephalitis.MethodsWe describe diagnostic workup, treatment and follow-up of a 54-year-old patient presenting with vertigo, unsteady gait, lack of drive and behavioral changes.ResultsClinical examination revealed severe cerebellar ataxia, saccadic smooth pursuit, upbeat-nystagmus, and dysarthria. Additionally, the patient presented with a depressive syndrome. MRI of the brain and spinal cord were normal. CSF analysis showed lymphocytic pleocytosis (11 cells/μl). Extensive antibody testing revealed anti septin-5 IgG in both CSF and serum without coexisting anti-neuronal antibodies. PET/CT detected no signs of malignancy. Corticosteroids, plasma exchange, and rituximab led to transient clinical improvement followed by relapse. Re-applied treatment with plasma exchange followed by bortezomib resulted in moderate but sustained clinical improvement.DiscussionAnti septin-5 encephalitis represents a rare but treatable and therefore relevant differential diagnosis in patients with cerebellar ataxia. Psychiatric symptoms can be observed in anti septin-5 encephalitis. Immunosuppressive treatment including bortezomib is moderately effective.

Case Presentation of Autoimmune Septin‐5 Cerebellar Ataxia

“…Typical of a septin-5 case, this patient had prominent diplopia and ataxia with Septin-5 antibodies in the CSF and serum. 7,8 There have been case reports of 8 to 15-day latency from COVID-19 infection onset of transient 2-8-week ataxia myoclonus syndromes, all with complete symptom resolution reported with initial immunosuppression. 6,9 COVID-19 infection cases have also included opsoclonus-myoclonus-ataxia syndromes.…”

Neuronal antibodies in nonparaneoplastic autoimmune cerebellar ataxias

“…Septin-5 antibodies have only been recently described, but in our opinion, they are good candidates to become biomarkers of ACA because their tight association with the syndrome and the preliminary experimental evidence that septin-5 antibodies may be pathogenic [36 ▪▪ ]. Up to now, 10 patients with septin-5 antibodies have been reported [37–39]. The median age was 59 years (range: 40–70 years) and seven patients were male.…”