Abstract Details

Title Autoimmune limbic encephalitis mimicking progressive supranuclear palsy

Topic Autoimmune Neurology

Presentation(s) P1 - Poster Session 1 (9:00 AM-5:00 PM)

Poster/Presentation
Number 038

Objective To describe a patient with autoimmune limbic encephalitis mimicking progressive supranuclear palsy (PSP)-like parkinsonism.

Background Autoimmune encephalitis presents various symptoms, including disturbance of consciousness, involuntary movements, and seizures. Several studies have described autoimmune encephalitis presenting parkinsonism-like neurodegenerative disorders. The importance of identifying autoimmune conditions should be emphasized because immunotherapies can improve these symptoms.

Design/Methods Case report.

Results An 81-year-old man was admitted to our hospital because of disturbance of consciousness and fever. He exhibited fever 1 month before admission and his consciousness level gradually decreased. On examination, neck rigidity, postural tremor, upper limb rigidity with a left-side predominance, and right lower limb myoclonus were observed. An electroencephalogram showed diffuse slow waves. Serum antibodies related to autoimmune encephalitis, including anti-Hu, anti-Ma2, anti-CRMP5, anti-GAD65, anti-GFAP, anti-LGI1, anti-CASPR2, and anti-IgLON5 antibodies, cerebrospinal fluid (CSF) N-methyl-D-aspartate receptor antibodies, and herpes simplex virus DNA were negative. The CSF cell count was 3/µl and the protein level was 55 mg/dl. CSF oligoclonal bands were positive and the immunoglobulin G index was elevated (1.18). Immunohistochemistry using rat cerebral frozen sections showed that the patient's serum and CSF immunoglobulin G reacted with hippocampal neurons. Brain magnetic resonance imaging showed T2 hyperintensities in the bilateral mesial temporal lobes and right basal ganglia. Dopamine transporter single-photon emission computed tomography revealed reduced ¹²³I-ioflupane accumulation in the bilateral striatum with a right-side predominance. The definite autoimmune limbic encephalitis criteria were fulfilled. We performed intravenous immunoglobulin therapy and methylprednisolone pulse therapy followed by oral prednisolone administration. The patient’s consciousness, fever, tremor, and rigidity gradually improved, and myoclonus disappeared. Striatal ¹²³I-ioflupane accumulation increased following treatment.

Conclusions

We report a patient with autoimmune limbic encephalitis presenting with axial rigidity mimicking PSP. Autoimmune limbic encephalitis rarely presents with PSP-like syndrome and responds to immunotherapies. Identification of the autoantibody responsible for this condition is necessary.

Authors/Disclosures
Yoya Ono PRESENTER	Mr. Ono has nothing to disclose.
Kazuhiro Higashida (Gifu university)	Kazuhiro Higashida has nothing to disclose.
Akio Kimura, MD (Gifu University Graduate School of Medicine)	Dr. Kimura has nothing to disclose.
Takayoshi Shimohata, MD, FAAN (Department of Neurology, Gifu University)	Dr. Shimohata has nothing to disclose.

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