Case report of meningoencephalitis associated with SARS-CoV-2 infection showing a decrease in idiopathic focal cerebral blood flow.

Some neurological complications are associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A 74-year-old man was diagnosed with infection by SARS-CoV-2. Eighteen days after SARS-CoV-2 infection, he developed disturbed consciousness and aseptic meningoencephalitis. An analysis of cerebrospinal flood revealed an elevated cell count (184/µL) and protein level (260 mg/dL). Cranial magnetic resonance imaging showed no abnormalities. By contrast, 123I-N-isopropyl-p-iodoamphetamine single-photon emission computed tomography showed a significant decrease in cerebral blood flow (CBF) in the left parietal and occipital lobes. He died suddenly 3 months after being transferred to a rehabilitation clinic without any clear cause of death. The SARS-CoV-2 infection can cause aseptic meningoencephalitis with a distinctive decrease in CBF pattern without magnetic resonance image abnormality or intracranial artery stenosis.

'Grasshopper sign': the novel imaging of post-COVID-19 myelopathy with delayed longitudinal white matter abnormalities.

Introduction: Recently, there have been a few reports of atypical post-coronavirus disease 2019 (COVID-19) myelopathy manifesting tract-specific lesions similar to those due to vitamin B12 deficiency. However, the precise characteristics of imaging or clinical course remain not well understood. Methods: A retrospective analysis of the clinical and imaging characteristics of four patients who were referred to our hospital with a unique post-COVID-19 myelopathy was performed. Results: Four-to-six weeks following COVID-19 infection in the summer of 2023, four middle-aged men developed paraparesis, hypo/dysesthesia and bladder/bowel disturbance, suggesting myelopathy. Although spinal MRI showed no abnormalities in the early stages, tract-specific longitudinal lesions along the dorsal and lateral columns became apparent as the symptoms progressed. Owing to the lack of MRI findings at the early stage, all cases were challenging to diagnose. However, the patients remained partially responsive to aggressive immunosuppressive therapies, even in the advanced stage. Discussion: We termed these tract-specific longitudinal lesions in the presented case series 'Grasshopper sign' because brain coronal and spine axial MRI findings looked like a grasshopper's antennae and face. Early identification of the characteristic MRI abnormality could allow for early intervention using intensive immunosuppressive therapy, which could improve patient outcomes.