Multiple system atrophy mimics CASPR2 antibody-associated disease: a case report.

Aim: Multiple system atrophy (MSA) and CASPR2 antibody-associated disease bear their own characteristics.Case presentation: 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.Conclusion: 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.

A case of herpes simplex virus induced peripheral neuropathy and encephalitis with positive GM3 and CASPR2 antibody.

BACKGROUND: We reported on a case involving an older patient with HSV-1 encephalitis who simultaneously experienced the onset of peripheral nerve symptoms associated with the presence of anti-GM3 immunoglobulin G (IgG). CASE PRESENTATION: A 77-year-old male was admitted to hospital with high fever, weakness of both lower limbs, and an unstable gait. A CSF test revealed a strikingly increased protein level (1,002 mg/L, normative values: 150-450 mg/L) and MRI revealed hyper-signal lesions in the right temporal lobe, right hippocampus, right insula, and right cingulate gyrus. The CSF was positive for HSV PCR (HSV-1,17870). In addition, the serum samples were positive for CASPR2 antibodies (antibody titer: 1/10) and anti-GM3 immunoglobulin G (IgG) (+). The patient was diagnosed with HSV-1-induced peripheral nerve symptoms that were associated with encephalitis and the presence of anti-GM3 IgG and anti-CASPR2 antibodies. The patient had received included intravenous immunoglobulin, intravenous acyclovir, and corticosteroids therapy. At the one-year follow-up examination, he had regained the necessary skills associated with daily life. CONCLUSIONS: Herpes simplex virus infection often induces encephalitis, and reaction to the virus may trigger an autoimmune response. Early diagnosis and treatment can avoid the progression of the disease to include autoimmune encephalitis.

Anti-CASPR2 antibody-associated autoimmune encephalitis： a case report / 四川精神卫生

This paper elaborated a case of an elderly patient with anti-contactin-associated protein-like 2 （CASPR2） antibody-associated autoimmune encephalitis. It illustrated the common manifestations and diagnostic process of anti-CASPR2 antibody-associated encephalitis， and the analysis of clinical symptoms and ancillary findings had contributed to gaining insight into the diagnosis of autoimmune encephalitis in elderly patients characterized by distinct psycho-behavioral abnormalities and cognitive decline， as well as suggesting the possibility that autoimmune encephalitis in elderly may exacerbate the development of cerebrovascular disease.

Seizure underreporting in LGI1 and CASPR2 antibody encephalitis.

Patients with anti-leucine-rich glioma-inactivated 1 protein (LGI1) or anti-contactin-associated protein 2 (CASPR2) antibody encephalitis typically present with frequent epileptic seizures. The seizures generally respond well to immunosuppressive therapy, and the long-term seizure outcome seems to be favorable. Consequentially, diagnosing acute symptomatic seizures secondary to autoimmune encephalitis instead of autoimmune epilepsy was proposed. However, published data on long-term seizure outcomes in CASPR2 and LGI1 antibody encephalitis are mostly based on patient reports, and seizure underreporting is a recognized issue. Clinical records from our tertiary epilepsy center were screened retrospectively for patients with LGI1 and CASPR2 antibody encephalitis who reported seizure freedom for at least 3 months and received video-electroencephalography (EEG) for >24 h at follow-up visits. Twenty (LGI1, n = 15; CASPR2, n = 5) of 32 patients with LGI1 (n = 24) and CASPR2 (n = 8) antibody encephalitis fulfilled these criteria. We recorded focal aware and impaired awareness seizures in four of these patients (20%) with reported seizure-free intervals ranging from 3 to 27 months. Our results question the favorable seizure outcome in patients with CASPR2 and LGI1 antibody encephalitis and suggest that the proportion of patients who have persistent seizures may be greater. Our findings underline the importance of prolonged video-EEG telemetry in this population.

Isaacs' syndrome as the initial presentation of malignant thymoma and associated with double-positive voltage-gated potassium channel complex antibodies, a case report.

BACKGROUND: Isaacs' syndrome is a peripheral nerve hyperexcitability (PNH) syndrome due to peripheral motor nerve instability. Acquired Isaacs' syndrome is recognized as a paraneoplastic autoimmune disease with possible pathogenic voltage-gated potassium channel (VGKC) complex antibodies. However, the longitudinal correlation between clinical symptoms, VGKC antibodies level, and drug response is still unclear. CASE PRESENTATION: A 45-year-old man had progressive four limbs soreness, muscle twitching, cramps, and pain 4 months before admission. Electromyography (EMG) studies showed myokymic discharges, neuromyotonia, and an incremental response in the high-rate (50 Hz) repetitive nerve stimulation (RNS) test. Isaacs' syndrome was diagnosed based on clinical presentations and EMG reports. Serum studies showed positive VGKC complex antibodies, including leucine-rich glioma-inactivated 1 (LGI1) and contactin-associated protein-like 2 (CASPR2) antibodies. The acetylcholine receptor antibody was negative. Whole-body computed tomography (CT) and positron emission tomography revealed a mediastinal tumor with the great vessels encasement, right pleura, and diaphragm seeding. Biopsy confirmed a World Health Organization type B2 thymoma, with Masaoka stage IVa. His symptoms gradually improved and both LGI1 and CASPR2 antibodies titer became undetectable after concurrent chemoradiotherapy (CCRT) and high dose steroid treatment. However, his Isaacs' syndrome recurred after the steroid was reduced 5 months later. Follow-up chest CT showed probable thymoma progression. LGI1 antibody turned positive again while CASPR2 antibody remained undetectable. CONCLUSIONS: Our patient demonstrates that Isaacs' syndrome could be the initial and only neuromuscular manifestation of malignant thymoma. His Isaacs' syndrome is correlated well with the LGI1 antibody level. With an unresectable thymoma, long-term immunosuppressant therapy may be necessary for the management of Isaacs' syndrome in addition to CCRT for thymoma.

Peripheral nerve hyperexcitability syndrome: A clinical, electrophysiological, and immunological study.

INTRODUCTION: Peripheral nerve hyperexcitability syndrome (PNHS) is characterized by muscle fasciculations and spasms. Nerve hyperexcitability and after-discharges can be observed in electrophysiological studies. Autoimmune mechanisms play a major role in the pathophysiology of primary PNHS. METHODS: We retrospectively conducted a case-control study recruiting patients with clinical and electrophysiological features of PNHS. Control patients were diagnosed with other neuronal or muscular diseases. Contactin-associated protein2 (CASPR2) and leucine-rich glioma-inactivated1 (LGI1) antibodies were examined. RESULTS: A total of 19 primary PNHS patients and 39 control patients were analyzed. The most common symptoms for the case group were fasciculations (11/19) and muscle spasms (13/19). Case group patients were likely to demonstrate electrodiagnostic findings of nerve hyperexcitability (17/19) and after-discharges in the tibial nerve (19/19). We found high prevalence of CASPR2 (9/19) and LGI1 (6/19) antibodies in the case group. DISCUSSION: Primary PNHS patients were likely to show after-discharges in the tibial nerve. The pathogenesis of PNHS is autoimmune CASPR2 and LGI1 antibodies are possible pathogenic antibodies for primary PNHS.

Contactin-associated protein-like 2 antibody-mediated neurological disease:clinical characters analysis of 12 cases / 中风与神经疾病杂志

@#Abstract Objective　To investigate clinical features,treatment and prognosis of patients with CASPR2-Ab associated neurological disease.Methods　The clinical data of 12 patients with CASPR2-Ab in Xuanwu Hospital,Capital Medical University from September 2016 to September 2019 were analyzed.Results　The age of 12 patients was 44.42±15.541 years old,and the ratio of male to female was 1∶1.Initial presenting symptoms comprised seizures (6/12),limb pain (2/12),limb weakness (3/12) and cerebellar speech (1/12).All patients developed central nervous system problems,presenting as seizures (8/12),mental abnormality (4/12) or memory decline (4/12).Five cases suffered from peripheral nervous system impairment,including muscle cramps (3/12),limb numbness (4/12),limb weakness (1/12),and neuropathic pain (2/12).Five patients got autonomic nervous system involved,manifested as hyperhidrosis.EMG showed abnormal spontaneous firing in four patients.Diffuse slow wave activity on background of EEG was found in six patients.Brain MRI in two cases showed hyperintensity lesions in bilateral temporal lobes on T2WI/FLAIR sequences,and tumor screening of one patient revealed benign thymoma.Ten patients got remission after immunotherapy.Conclusion　CASPR2-Ab associated disease tended to be susceptible to elderly male and middle-aged female,which extensively affected various nervous system.Early immunotherapy was effective in patients,especially those with seizure as the only symptom or with limbic encephalitis.

Corrigendum: Sleep Disorders in Leucine-Rich Glioma-Inactivated Protein 1 and Contactin Protein-Like 2 Antibody-Associated Diseases.

[This corrects the article DOI: 10.3389/fneur.2020.00696.].

Anti-CASPR2 antibody associated encephalitis with anosmia and demyelinating pseudotumor: A case report.

A 20-year-old female presented with fine motor deficits and visual field defect was admitted to our hospital. CSF tests for autoimmune encephalitis antibodies and onconeuronal antibodies were unremarkable. MRI showed unilateral lesion involving left basal ganglia, external capsule, insula, hippocampus, and amygdala, which was considered to be demyelinating pseudotumor after surgical intervention. The patient's symptoms relieved so she didn't consent to immunotherapy. Two years and a half later our patient reported sudden anosmia. Reexamination by MRI demonstrated a new lesion. We then detected anti-CASPR2 antibodies in the patient's serum and gave her immunotherapy.

Clinical characteristics of patients double positive for CASPR2 and LGI1-antibodies.

OBJECTIVES: This study described the clinical characteristics of autoimmune neurological diseases with dual seropositive antibodies of CASPR2 and LGI1. PATIENTS AND METHODS: Three patients, with antibodies targeting both CASPR2 and LGI1 (EUROIMMUN, FA 112d-1, Germany), hospitalized in Department of Neurology, Xuanwu Hospital, Capital Medical University from June 2016 to June 2019 were collected in this study. We summarized the clinical characteristics of patients with CASPR2 and LGI1 antibodies from a targeted literature review. RESULTS: Three patients reported were all middle-aged and elderly male with diverse neurological symptoms, including seizures, psychological abnormalities, limb weakness and hyperhidrosis. Interestingly, three patients displayed three different clinical syndromes (isolated epilepsy, Morvan syndrome and limbic encephalitis, respectively). White blood cell and glucose in Cerebrospinal fluid (CSF) were normal and CSF for protein was slightly elevated. Electromyography (EMG) showed abnormal spontaneous firing in case 2. Brain magnetic resonance imaging (MRI) revealed bilateral hyper-intensity of the temporal lobe on T2 and FLAIR sequence in case 3. Cancer screening program of patient 2 showed thymoma. Cell based assay was positive in serum for both LGI1 and CASPR2 antibodies, while these antibodies were negative in CSF. They were treated with glucocorticoid or intravenous immunoglobulin (IVIG). Followed up for 6 months to 1 year, all patients got remission to different extent. CONCLUSION: Through the detailed analysis of three patients, the combination of both antibodies contributes to a broad spectrum of neurological symptoms in the central, peripheral, and autonomic nervous systems. The patients with same antibodies can have different clinical syndromes. Early tumor screening and immunotherapy will improve the prognosis of the disease.

Sleep Disorders in Leucine-Rich Glioma-Inactivated Protein 1 and Contactin Protein-Like 2 Antibody-Associated Diseases.

Objective: Sleep disorders are common in voltage-gated potassium channel complex antibody (VGKC-Ab) diseases. The aim was to investigate the sleep disturbances and polysomnography (PSG) characteristics in patients with VGKC-Ab-associated diseases. Methods: Twenty-seven patients with leucine-rich glioma-inactivated protein 1 antibody (LGI1-Ab) encephalitis, seven patients with contactin protein-like 2 antibody (Caspr2-Ab)-associated diseases, and 14 healthy controls with at least one PSG or actigraphy recording were recruited at Peking Union Medical College Hospital from January 2014 to July 2019. Results: Sleep disorders including insomnia, hypersomnia, rapid eye movement (REM) sleep behavior disorder (RBD), periodic limb movements in sleep (PLMS), agrypnia excitata, and obstructive sleep apnea syndrome were observed. Twenty-one PSG recordings from patients with LGI1-Ab encephalitis demonstrated a decrease in total sleep time (TST) (median 365.5, range 184.5-495.5 min), sleep efficiency (70.0%, 47-92%), N3 sleep (9.7%, 0-32.9%), and REM sleep (9.9%, 0.4-27.9%). Of five patients with Caspr2-Ab-associated diseases, TST was found to be 329.5 (167.0-377.5 min), and sleep efficiency was found to be 61.7% (34.6-71.7%). The percentage for N3 and REM sleep was found to be 15.0% (0-34.6%) and 12.7% (0-22.2%), respectively. Both RBD and PLMS were observed more frequently in patients with LGI1-Ab encephalitis. We identified status dissociatus (SD) in five (23.8%) patients with LGI1-Ab encephalitis and two (40%) patients with Caspr2-Ab diseases. The former is more likely to have simple limb movements rather than complex movements, which mimic the contents of their dreams. Continuous insomnia was more common in patients with Caspr2-Ab diseases than patients with LGI1-Ab encephalitis. Patients reported clinical and PSG improvements following immunotherapy. Conclusion: Sleep disorders in patients with VGKC-Ab-associated diseases include decreased TST and poor sleep efficiency. Our studies provide evidence of SD in patients with LGI1-Ab encephalitis.

Limbic encephalitis in a neuroscientist: CASPR 2 antibody-associated disease after antigen exposure.

Autoimmune limbic encephalitis is part of CASPR 2 antibody-associated disease. A man with this rare disorder and a very high antibody titre had a unique history of laboratory exposure to the antigen. Together with earlier observations this case calls for caution in laboratory handling of nerve tissue.

[Clinical analysis of 7 cases with anti-Caspr2 antibody-associated autoimmune encephalitis].

Objective: To investigate the clinical features, laboratory tests, imaging features, electroencephalogram (EEG) manifestations, treatment and prognosis of anti-CASPR2 antibody-associated autoimmune encephalitis with the purpose to improve the understanding of the disease. Methods: Seven patients diagnosed with CASPR2 antibody-associated encephalitis in the Fifth and first Affiliated Hospital of Zhengzhou University from January 2017 to January 2019 were selected. The clinical manifestations, course of disease, imaging, treatment plan and prognosis of the patients were retrospectively analyzed. Results: Of the 7 patients, 4 were male and 3 were female. The median age of onset was 34 years old (range, 11-66 years). Seizures (6/7), memory decline(5/7), and neuropsychiatric disorders (4/7) were common clinical manifestations. CASPR2 antibody was detected in the CSF of 3 patients (3/7) and the serum of all patients (7/7). Notable imaging changes were observed in 5 patients (5/7). All patients received immunotherapy and were followed up for 1 month to 2 years. One patient was diagnosed with rectal cancer with a poor prognosis; all the others got a good prognosis. Conclusions: CASPR2 antibody-related encephalitis is a rare autoimmune disease. It is considered to present with seizures, memory loss, psychiatric symptoms, dizziness and sleep disorders as the main clinical manifestations. Early identification and treatment of the disease can help the patients achieve a good prognosis.

Systematic review of the clinical spectrum of CASPR2 antibody syndrome.

BACKGROUND: Contactin-associated protein-like 2 (CASPR2) autoantibody disease has a variable clinical phenotype. We present a case report and performed a systematic review of the literature to summarize: (1) the clinical phenotype of patients with CASPR2 antibodies, (2) the findings in neurological investigations, and (3) the associated neuroimaging findings. METHODS: A chart review was performed for the case report. A systematic review of the medical literature was performed from first available to June 13, 2018. Abstracts were screened, and full-text peer-reviewed publications for novel patients with CASPR2 positivity in serum or cerebrospinal fluid (CSF) were included. Selected publications were reviewed, and relevant information was collated. Data were analyzed to determine overall frequency for demographic information, clinical presentations, and investigation findings. RESULTS: Our patient was a previously healthy 61-year-old male with both serum and CSF CASPR2 antibodies who presented with limbic encephalitis and refractory epilepsy. He was successfully treated with immunosuppression. For our systematic review, we identified 667 patients from 106 studies. Sixty-nine percent were male. Median age was 54 years (IQR 39-65.5). Median disease duration was 12 months (IQR 5.6-20). Reported overall clinical syndromes were: autoimmune encephalitis [69/134 (51.5%)], limbic encephalitis [106/274 (38.7%)], peripheral nerve hyperexcitability [72/191 (37.7%)], Morvan syndrome [57/251 (22.7%)], and cerebellar syndrome [24/163 (14.7%)]. Patients had positive serum [642/642 (100%)] and CSF [87/173 (50.3%)] CASPR2 antibodies. MRI was reported as abnormal in 159/299 patients (53.1%), and the most common abnormalities were encephalitis or T2 hyperintensities in the medial temporal lobes, or hippocampal atrophy, mesial temporal sclerosis, or hippocampal sclerosis. FDG-PET was abnormal in 30/35 patients (85.7%), and the most common abnormality was temporomesial hypometabolism. The most commonly associated condition was myasthenia gravis (38 cases). Thymoma occurred in 76/348 patients (21.8%). Non-thymoma malignancies were uncommon [42/397 (10.6%)]. CONCLUSIONS: Most patients have autoimmune or limbic encephalitis and corresponding abnormalities on neuroimaging. Other presentations include peripheral nerve hyperexcitability or Morvan syndromes, cerebellar syndromes, behavioral and cognitive changes, and more rarely movement disorders. The most commonly associated malignancy was thymoma and suggests a role for thymoma screening in CASPR2-related diseases.

A Patient with Limbic Encephalitis Associated with Anti-leucine-rich Glioma-inactivated 1 (LGI1) Antibody Presenting with Slowly Progressive Cognitive Impairment and Fluctuating Striatal Lesions.

We herein report the case of a 59-year-old man with anti-leucine-rich glioma-inactivated 1 (LGI1) antibody encephalitis who presented with slowly progressive cognitive impairment mimicking dementia for over 3 years and then developed seizures. Unique brain magnetic resonance imaging (MRI) findings of fluctuating striatal lesions were observed during the disease course. He was treated with intravenous methylprednisolone pulse therapy followed by oral prednisolone, which dramatically improved his neurological function. Taken together, these findings indicate that anti-LGI1 encephalitis may present as slowly progressive cognitive impairment mimicking dementia and that fluctuating MRI striatal lesions may be a characteristic radiological finding of this disorder.

Isaacs syndrome with CASPR2 antibody: A series of three cases.

Isaacs syndrome is a form of peripheral nerve hyperexcitability, characterized by spontaneous muscle twitching and stiffness. Some patients are reported to be positive for CASPR2 antibody that may be one of the pathogenic autoantibodies in Isaacs syndrome. We reported a series of three patients with Isaacs syndrome, including their clinical features, electrophysiologic findings, laboratory parameters and therapeutic responses. All the three patients were positive for CASPR2 antibodies examined on transfected human embryonic kidney 293 cells by indirect immunofluorescence method. One patient had invasive thymoma. Symptomatic treatment was not sufficient for them, while immunotherapies including corticosteroids, double filtration plasmapheresis and rituximab provided favorable outcomes. The titers of CASPR2 antibody decreased after immune modulating therapy in parallel to clinical improvements in two patients.

Eyelid tremor in a patient with anti-caspr2 antibody-related encephalitis.

We describe the first case of a patient with eyelid tremor probably associated with anti-contactin-associated protein-like 2 (Caspr2) antibody. Encephalitis associated with anti-voltage-gated potassium channel antibody is now attributed to autoantibodies against leucine-rich glioma inactivated 1 (Lgi1) and less frequently against Caspr2. Eyelid tremor or blepharoclonus is a rare or underdiagnosed involuntary movement that has been found in patients with infarction in the thalamus or drug-induced or idiopathic parkinsonism. Since patients with anti-Caspr2 antibody-related encephalitis occasionally have extrapyramidal signs, we speculate that the eyelid tremor was also caused by anti-Caspr2 antibody in our patient. Partial resolution of his symptoms by plasmapheresis also supported the involvement in immunological processes.

Hemichorea Associated with CASPR2 Antibody.

This letter was written in response to: Ramdhani RA, Frucht SJ. Isolated chorea associated with LGI1 antibody. Tremor Other Hyperkinet Mov. 2014; 4. doi: 10.7916/D8MG7MFC.

Reply to: Hemichorea Associated with CASPR2 Antibody.

This letter was written in reply to this letter to the editor: Vynogradova I, Savitski V, Heckmann JG. Hemichorea associated with CASPR2 antibody. Tremor Other Hyperkinet Mov. 2014; 4. doi: 10.7916/D8VM49C5. The above letter to the editor was written in response to this article: Ramdhani RA, Frucht SJ. Isolated Chorea Associated with LGI1 Antibody. Tremor Other Hyperkinet Mov. 2014; 4. doi: 10.7916/D8MG7MFC.