Lambert-Eaton Myasthenic Syndrome Complicated by anti-GABAB Receptor Encephalitis.

A 74-year-old man experienced diplopia, generalized muscle weakness, and acute respiratory failure. He was diagnosed with Lambert-Eaton myasthenic syndrome (LEMS) and treated with immunotherapy, but no improvement was observed, and additional symptoms, including central apnea and hallucinations, appeared. Subsequent serum and cerebrospinal fluid (CSF) analyses confirmed the presence of GABAB receptor antibodies, indicating the coexistence of autoimmune encephalitis. Although there were no findings of malignancy, it is highly likely that occult small-cell lung carcinoma was present. When atypical symptoms occur in patients with LEMS, it is important to consider the possibility of concomitant autoimmune encephalitis.

[Diagnosis of cryoglobulinemic vasculitis based on B symptoms and peripheral neuropathy: a case report].

A man in his 50s presented with a 2-month history of paresthesia and hypoesthesia of the extremities and B symptoms including low-grade fever, weight loss, and night sweats. He also reported a 3-year history of skin discoloration in cold weather. Laboratory test results showed a high white blood cell count and elevated serum C-reactive protein and rheumatoid factor (RF) levels. Complement levels were low, and tests for cryoglobulin showed positive results. Computed tomography revealed generalized lymphadenopathy, and 18F-fluorodeoxyglucose-positron emission tomography showed increased uptake; therefore, we performed cervical lymph node and muscle biopsies. The patient was diagnosed with nodular marginal zone lymphoma and cryoglobulinemic vasculitis (CV) and received chemotherapy and steroid treatment with improvement in symptoms. CV is a rare immune complex small-vessel vasculitis. It is important to measure RF and complement levels and consider infections, collagen diseases, and hematological disorders in the differential diagnosis in patients with suspected vasculitis or CV.

Clinical features of anti-mitochondrial M2 antibody-positive myositis: case series of 17 patients.

OBJECTIVE: In 2012, a large number of myositis cases with anti-mitochondrial M2 (AMA-M2) antibody, which had well been known as the serological hallmark for primary biliary cholangitis (PBC), were reported in Japan. Recently, some case series from Japan, France, America, China and India have shown that approximately 2.5% to 19.5% of patients with myositis have AMA-M2 antibody. The objective of this study was to clarify the prevalence, clinical features, treatment outcome, and severity determinants of AMA-M2 positive myositis. METHODS: This study was a multicenter observational study. We enrolled patients who were diagnosed with myositis during a ten-year period between 2012 and 2021. RESULTS: Of the total of 185 patients with inflammatory myopathy, 17 patients were positive for AMA-M2 antibody. The typical symptoms were weakness mainly involving paravertebral muscles, weight loss, respiratory failure, and cardiac complications. Thirteen of the 17 patients had cardiac complications. A strong correlation was found between respiratory failure and modified Rankin Scale (mRS) score. A strong correlation was also found between respiratory failure and body weight, indicating that weight loss can be an indicator of potential progression of respiratory failure. Six of the 17 patients were complicated by malignancy. CONCLUSIONS: This study showed significant correlations between % vital capacity (VC), body mass index (BMI), and mRS score in patients with AMA-M2-positive myositis. Immunotherapy often improved CK level and respiratory dysfunction. We therefore propose that %VC and BMI should be monitored as disease indicators in treatment of AMA-M2-positive myositis.

Hashimoto's encephalopathy mimicking a brain tumor and its pathological findings: A case report.

Hashimoto's encephalopathy is characterized by the presence of anti-thyroid antibodies with no alternative cause. Patients with Hashimoto's encephalopathy present with various clinical symptoms and magnetic resonance imaging (MRI) findings. To our knowledge, this is the first documented report of Hashimoto's encephalopathy with MRI findings mimicking a brain tumor. The patient was a 41-year-old woman with a history of Hashimoto's disease. She experienced gradually worsening Parkinsonism and an MRI revealed a brain tumor-like lesion at the left caudate nucleus. She underwent a brain biopsy that revealed diffuse gliosis and perivascular lymphocyte infiltration with CD3+ T-cell predominance. No pathological signs of a brain tumor were found. Hashimoto's encephalopathy was suspected based on the patient's history and the presence of anti-thyroid antibodies. Her symptoms and the MRI findings improved with glucocorticoid treatment. Although there exist only a few studies on the pathology of Hashimoto's encephalopathy, our findings were consistent with those of previous reports. Our findings suggest cerebral vasculitis as an underlying etiology of Hashimoto's encephalopathy. We also emphasize the importance of considering Hashimoto's encephalopathy as a differential diagnosis of brain tumors.