Purpose: The purpose of this study was to elucidate the diagnostic predictive factors of listeria meningitis. Subjects and Method: Twenty-eight patients with bacterial meningitis (age; 65.9 ± 14.8 years, 11 female) who were admitted to Chikamori Hospital from October 1, 2006 to December 31, 2021 were included. Bacterial meningitis was defined as cerebrospinal fluids (CSF) pleocytosis with evidence of bacterial infection in CSF or blood. The blood and CSF data were reviewed for analysis. Results: 9 patients were diagnosed as listeria meningitis, 19 patients were in non-listeria meningitis. Multiple logistic regression analysis showed that higher CSF lymphocyte ratio was significantly associated with listeria meningitis (Odds ratio 1.123, 95% Confidence interval 1.006–1.2155, P = 0.039). CSF lymphocyte ratio of 30% or more was found to predict listeria meningitis with a sensitivity of 55.6% and a specificity of 100%. Conclusion: CSF lymphocyte ratio may be useful for differentiating between listeria meningitis and non-listeria meningitis.

We report a case of non-fluent/agrammatic variant of primary progressive aphasia in a 79-year-old right-handed man who was admitted with a 5-year history of non-fluent speech and apraxia of speech. He also presented with agrammatism and logoclonia (the meaningless repetition of the middle or final syllable of a word). Furthermore, brain MRI revealed atrophy of the bilateral frontal and temporal lobes, while N-isopropyl-p-¹²³I-iodoamphetamine single-photon emission computed tomography (SPECT) revealed relative hypoperfusion in the right basal ganglia. In addition, dopamine transporter SPECT revealed a decrease in specific binding ratio values, indicating neural dopamine dysfunction, which led to his diagnosis of progressive non-fluent aphasia with logoclonia. Logoclonia is a severe linguistic dysfunction usually observed in the advanced stages of Alzheimer’s disease. However, based on the clinical course and cerebrospinal fluid evaluation results, our patient did not show any features of Alzheimer’s disease. Thus, logoclonia might be associated with lesions involving the basal ganglia, right hemisphere, and left frontotemporal lobe.

A 52-year-old male was carried to hospital by ambulance, because of an abrupt abnormal behavior and impaired consciousness. Soon after the arrival, the patient started a generalized seizure. Although the seizure was stopped by Midazolam, amnesia were observed. With meningeal irritation signs, in addition to the clinical course, the patient was thought to develop limbic encephalitis. The cause of the encephalitis was diagnosed as neurosyphilis because of the positive serum and CSF syphilis reactions, and the patient was treated with penicillin G from the first admission day on. Steroid pulse therapy was also conducted, followed by acyclovir since herpes encephalitis could not be ruled out; the brain MRI showed left-side dominant T₂/FLAIR high intensity lesions in the bilateral temporal lobes and left hippocampus. With the treatment progression, the amnestic syndrome improved and the patient returned to work. Although neurosyphilis is a rare cause of acute onset limbic encephalitis, it is important to keep the possibility of this disease in mind in making a treatment plan.

A 72-year-old male complained of fever lasting 1 month and developed muscle weakness and paresthesia in the legs. He presented with muscle weakness, grasping pain, decreased deep tendon reflexes in the extremities, and reduction of tactile sensation in the distal parts of the left leg muscles. Blood tests revealed leukocytosis and inflammatory reactions. Collagen-disease-specific autoantibodies including anti-double-stranded DNA and anti-Scl-70 antibodies were positive, but antineutrophil cytoplastic antibodies were negative. Nerve conduction studies revealed asymmetric axonal degeneration, indicating multiple mononeuropathy. We started intravenous methylprednisolone pulse and plasma exchange therapies. However, the patient developed intestinal necrosis and perforation, and he died 44 days after the onset of fever. An autopsy revealed vasculitis in small- to medium-sized vessels in multiple organs as well as myoglobin casts in the renal tubules, which were suggestive polyarteritis nodosa (PAN) accompanied with rhabdomyolysis. Positivity for collagen-disease-specific autoantibodies and accompanying rhabdomyolysis are atypical findings with PAN. This patient was not clinically diagnosed as PAN, and so promptly starting immunotherapies should be considered when a case presents with evidence of vasculitis.

A 55-year-old man presented a slowly progressive sensory disorder, predominantly in both lower limbs, and gait disturbance. Neurological examinations revealed abnormal sensation and spasticity in both lower limbs, and a wide-based gait. Although examination revealed mild hyperchloremia and decreased motor conduction velocity in the peroneal nerve, head and whole spine MRI, and spinal fluid examination were normal. His job history revealed he had been engaged in metal cleaning work using 1-bromopropane (1-BP) for three years. His serum bromide concentration was increased to 175.6 mg/l (standard value: 5 or less), so we diagnosed him as having 1-BP neurotoxicity. The serum bromide concentration decreased after avoidance of exposure to 1-BP, but the gait disturbance remained. It was considered that we should obtain a detailed job history and measure the serum bromide concentration in patients with a sensory disorder in the extremities and gait disturbance of unknown origin.

An 80-year-old woman presented with subacute right lower limb pain and bilateral lower limb weakness. MRI of the spine showed marked cauda equina enlargement with contrast enhancement. Cerebrospinal fluid (CSF) examination showed elevated cell count, decreased glucose, and elevated protein. Cytology of the CSF showed class V, which together with B-cell clonality by flow cytometry, led to the diagnosis of primary central nervous system lymphoma (PCNSL). The patient was treated with steroid, radiation, and chemotherapy. Despite the reduction in lesion size, her neurological symptoms revealed no improvement. PCNSL with cauda equina lesions are rare and often require highly invasive cauda equina biopsy for diagnosis. In recent years, some studies reported useful CSF biomarkers, but they may have some problems. Therefore, as in this case, the combination of cytology, flow cytometry and, CSF biomarkers could be a substitute method for invasive biopsies, and contribute to the early treatment of PCNSL.

We report a 57-year-old man with multiple sclerosis since his 30s who was treated with fingolimod for 9 years. He developed left hemiparesis and consciousness disturbance. Brain MRI revealed a mass lesion in the right frontal lobe with gadolinium enhancement. Cerebrospinal fluid examination showed no pleocytosis. The lesion continued to expand after admission, and on the 9th day after admission, decompressive craniectomy and brain biopsy were performed. Brain pathology revealed demyelination in the lesion, leading to the diagnosis of a tumefactive demyelinating lesion. Corticosteroid therapy ameliorated the brain lesion, and we inducted natalizumab. Tumefactive demyelinating lesions requiring decompressive craniotomy are rare, and we report this case for the further accumulation of similar cases.