We treated 437 cases of adult aseptic meningitis and 12 cases (including 2 recurrent patients; age, 31.8 ± 8.9 years; 7 females) of herpes simplex meningitis from 2004 to 2016. The incidence rate of adult herpes simplex meningitis in the cases with aseptic meningitis was 2.7%. One patient was admitted during treatment of genital herpes, but no association was observed between genital herpes and herpes simplex meningitis in the other cases. The diagnoses were confirmed in all cases as the cerebrospinal fluid (CSF) was positive for herpes simplex virus (HSV)-DNA. For diagnosis confirmation, the DNA test was useful after 2–7 days following initial disease onset. Among other types of aseptic meningitis, the patients with herpes simplex meningitis showed relatively high white blood cell counts and relatively high CSF protein and high CSF cell counts. CSF cells showed mononuclear cell dominance from the initial stage of the disease. During same period, we also experienced 12 cases of herpes simplex encephalitis and 21 cases of non-hepatic acute limbic encephalitis. Notably, the patients with herpes simplex meningitis were younger and their CSF protein and cells counts were higher than those of the patients with herpes simplex encephalitis.

A 74-year-old man with a past medical history of bradycardiac atrial fibrillation and an old cerebral infarction presented with dysarthria. He had been treated with warfarin and PT-INR on admission was 2.0. MRI of the head revealed an acute ischemic stroke involving the cerebellum and left occipital lobe. Because transesophageal cardiac echography showed a thrombus in the left atrial appendage, anticoagulant treatment with warfarin and heparin was initiated. The thrombus was enlarging; therefore, we changed the anticoagulant therapy to apixaban with heparin on day 11. On day 17, a hemorrhagic cerebral infarction occurred. After the hemorrhage diminished, we treated him with warfarin aiming for a PT-INR between 3 and 4. The thrombus gradually shrank and disappeared on day 110. Finally, a thoracoscopic left atrial appendectomy was performed as a secondary prevention, with no recurrence till date.

A 76-year-old woman showed a dramatic lowering of her tone of voice in October 2014, followed by muscle weakness of the left arm. The previous attending physician noticed remarkable left dominant frontotemporal lobe atrophy on cranial MRI. Her dysarthria, dysphagia and the muscle weakness of her extremities worsened, and a muscle biopsy revealed mitochondrial abnormality. The mitochondrial DNA from her muscle showed multiple deletions; the previous physician therefore diagnosed the patient with mitochondrial disease. The patient resembled amyotrophic lateral sclerosis-frontotemporal dementia (ALS-FTD). No other cases of ALS-FTD with mitochondrial disease have been reported in Japan. We therefore consider the present case to be valuable.

A 40-year-old man visited our department because of chest and back pain. He had a history of diagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP) 20 years ago. He received immunosuppressive therapy and had no relapses after that. On Admission, MRI showed tuberous hypertrophy of the spinal roots, intercostal nerves, and brachial and lumbar plexuses. The genetic analysis showed no mutations in any of Charcot-Marie-Tooth related genes. He was finally diagnosed with CIDP and administration of high dose intravenous methylprednisolone relieved his chest and back pain within a few days. We present a rare case of CIDP in which showed marked enlarged spinal roots in long clinical course and have a relapse with radicular pain without sensorimotor symptoms.

A 19-year-old woman developed high fever, headache, and nausea after taking Loxoprofen for pharyngitis, followed by disturbed consciousness and nuchal stiffness. The patient and her mother had a history of Raynaud’s phenomenon. Cerebrospinal fluid (CSF) examination indicated a diagnosis of aseptic meningitis and revealed high levels of Q albumin and IgG index. Anti-RNP antibodies were positive in serum and CSF. Her symptoms disappeared immediately after cessation of Loxoprofen and a drug lymphocyte stimulation test was negative, confirming a diagnosis of non-steroidal anti-inflammatory drugs (NSAIDs)-induced aseptic meningitis. It should be kept in mind that an immune abnormality such as serum and CSF anti-RNP antibodies may play a role in development of NSAIDs-induced aseptic meningitis. A history of usage of NSAIDs and a thorough examination of collagen diseases are useful for identification of the origin of aseptic meningitis in a young woman.

A 43-year-old man without a previous episode of uveitis presented with slowly progressive neurological symptoms that appeared within the past year such as dysarthria, ataxic gait, and behavioral changes. Brain MRI findings showed atrophic lesions in the brainstem and cerebellum. Because these clinical symptoms and abnormal MRI findings indicated spinocerebellar degeneration as the initial diagnosis, he was admitted to our hospital. On admission, we noticed that he had non-neurological manifestations of Behçet disease, such as stomatitis, genital ulcers, and folliculitis. HLA-B51 was positive. He also showed pleocytosis (29 cells/mm³, predominantly mononuclear cells) and elevated cerebrospinal fluid (CSF) IL-6 levels (213 pg/ml), hence he was diagnosed with chronic progressive neuro-Behçet disease (CPNBD). The therapeutic effect of a high-dose intravenous methylprednisolone pulse (1,000 mg/day for 3 days) and methotrexate (maximum dosage, 16 mg/week) was poor against both neurological symptoms and CSF findings. Intravenous infliximab therapy (5 mg/kg, 2 weeks) dramatically decreased CSF IL-6 levels (13 pg/ml) but clinical symptoms remained unchanged. MRI findings of extensive cerebral atrophy and increased CSF IL-6 levels at the pretreatment time point reflected irreversible neurological involvement in CPNBD. For cases with progressive psychiatric symptoms and cerebellar ataxia in the early stage of the disease, skin manifestations should be examined immediately, CSF IL-6 levels measured, and immunosuppressive therapy initiated before CPNBD progresses to brainstem atrophy.

A 80-years-old woman suddenly presented with aphasia, right hemiparesis, and dysesthesia. MRA showed the left middle cerebral artery occlusion. She was diagnosed as hyperacute ischemic stroke. She was treated with intravenous recombinant tissue plasminogen activator and underwent endovascular thrombectomy. On admission, she had a fever and high C reactive protein, and was treated with antibiotic therapy. The pathological diagnosis of the retrieved thrombus revealed the cluster of the gram positive cocci. The blood culture was negative and thransthoracic echocardiogram did not detect the vegetation. She was finally diagnosed as cardioembolic stroke due to infective endocarditis based on the pathological diagnosis of the retrieved thrombus. The pathological diagnosis of the retrieved thrombus was quite important to clarify the cause of ischemic stroke.

The present patient was an 87-year-old man who had been taking cibenzoline for tachyarrhythmia. Five years after initiation of administration, he was referred to our hospital for ptosis that worsened from midday, as well as weakness of the facial and limb muscles. He tested negative for anti-acetylcholine receptor antibody but positive in the edrophonium test, suggesting that he had myasthenia gravis. He was admitted to our hospital 3 years later due to worsening symptoms of ptosis and muscle weakness. He had hypoglycemia, cardiac conduction defect, and renal dysfunction. In addition, blood concentration of cibenzoline was markedly high (1,850 ng/ml). We terminated the administration of cibenzoline, after which the patient’s neurologic symptoms improved. Our findings suggest that cibenzoline toxicity must be considered in differentiating myasthenia gravis when a patient also presents with renal dysfunction.

This report presents a case of a 71-year-old woman with Fisher syndrome who had posterior reversible encephalopathy syndrome (PRES) before the initiation of intravenous immunoglobulin (IVIg) treatment. She had symptoms of common cold 2 weeks before the onset of PRES. On the day of the onset, she began to stagger while walking. On day 2, she developed hypertension, vision impairment, and limb weakness and was admitted to the hospital. On day 3, she was provided steroid pulse therapy. On day 4, she developed convulsions and right imperfection single paralysis and was transferred to the our hospital. During the transfer, the patient was conscious. Her blood pressure was high at 198/107 mmHg. She had mild weakness in her limbs and face, light perception in both eyes, dilation of both pupils, total external ophthalmoplegia, no tendon reflexes, and limb and trunk ataxia. We diagnosed PRES because of the high signal intensities observed on T₂-weighted MRI on both sides of the parietal and occipital lobes. We also diagnosed Fisher syndrome because of a positive anti-GQ1b immunoglobulin G antibody test and albuminocytologic dissociation in the cerebrospinal fluid. PRES showed prompt improvement with antihypertensive therapy, whereas Fisher syndrome slowly improved over a course of 2 months. This case is the first report of PRES without IVIg suggesting that Fisher syndrome induces hypertension and causes PRES.