Multiple system atrophy mimics CASPR2 antibody-associated disease: a case report
Creators: name: Chen, Xiaoli
name: Feng, Li
name: Li, Jing
name: Jiang, Hong
Publisher: name: Taylor & Francis
Year: 2024
Subjects: subject: Medicine
subject: Cell Biology
subject: Genetics
subject: FOS: Biological sciences
subject: Neuroscience
subject: Physiology
subject: Biotechnology
subject: Immunology
subject: FOS: Clinical medicine
subject: Cancer
subject: Mental Health
subject: Hematology
subject: Cardiology

description: <b>Aim:</b> Multiple system atrophy (MSA) and CASPR2 antibody-associated disease bear their own characteristics. <b>Case presentation:</b> A 58-year-old woman presented with a 26 months history of uncoordinated gait and slurred speech. Her serum was positive for anti-CASPR2 antibodies, and MRI revealed atrophy of the brainstem and cerebellum. She underwent three plasma exchanges (PE) and received high doses of corticosteroids without any apparent effect. Her autonomic dysfunction improved after repetitive transcranial magnetic stimulation. Eventually, a diagnosis of MSA-cerebellar phenotype(MSA-C) was made. <b>Conclusion:</b> With increased availability of tools for neuron antibody detection, physicians need to be aware of the possibility that antibodies may accompany other diseases. This report underscores the modern dilemmas caused by available and extensive neuron antibody testing. There is a certain degree of difficulty in diagnosis of MSA, especially in the early stage and it is easy to be confused with degenerative diseases such as PD. With a thoroughly study of autoimmune diseases of the nervous system, it was found that the clinical symptoms of CASPR2-associated disease overlapped with MSA. In this report, a 58-year-old woman was reported to have uncoordinated gait and slurred speech, and anti-CASPR2 antibodies were found in the blood and cerebrospinal fluid for multiple times, which brought great challenges to the diagnosis. After immunotherapy, anti-CASPR2 antibodies titers declined, but the clinical symptoms and brainstem and cerebellar atrophy were exacerbated, MSA-C was finally diagnosed and rTMS treatment seems helpful. MSA is hard to be distinguished clinically from other disorders, particularly in early stages. Pathological biopsy is difficult to perform, which is decisive for diagnosis. MRI ‘hot cross bun’ sign and ‘putaminal rim’ sign have a certain specificity for MAS of diagnosis, with specificity of 97% and 90%, respectively. CASPR2 antibody-associated disease has seven core symptoms, namely cerebral symptoms, cerebellar symptoms, peripheral nerve hyperexcitability, autonomic dysfunction, insomnia, neuropathic pain and weight loss. And some of its symptoms are similar to those of MSA. We firstly reported a patient with potential MSA-C who exhibits symptoms of cerebellar ataxia, parkinsonism, insomnia, weight loss, frequent upper lid twitch, poor response to levodopa, anti-CASPR2 antibodies in the serum and pons and cerebellum atrophy. The patient of the current report was used to be misdiagnosed as anti-CASPR2 encephalitis and received immunotherapy, the anti-CASPR2 antibodies titers declined, but the clinical symptoms and brainstem and cerebellar atrophy were exacerbated. Anti-CASPR2 antibodies are rarely seen among MSA patients. If dystonia and autonomic symptoms patients with anti-CASPR2 antibodies, follow-up MRI is required, to confirm the presence of brainstem and cerebellar atrophy to avoid missed diagnosis. Anti-CASPR2 antibodies are not always pathogenic antibodies, while the IgG titer is lower than 1:200.