Risk Factors Related to Severity in COVID-19 Patients: A Real-world Retrospective Cohort Study.

Objective Understanding the clinical factors associated with the severity of coronavirus disease 2019 (COVID-19) is very important for the effective use of limited medical resources, including the appropriate evaluation of the need for hospitalization and discharge. Methods Patients hospitalized with a diagnosis of COVID-19 from March 2021 to October 2022 were included in the study. Patients admitted to our facility were classified into four waves: 4th (April to June 2021), 5th (July to October 2021), 6th (January to June 2022), and 7th waves (July to October 2022). We analyzed the severity, patients' background characteristics, presence of pneumonia on chest computed tomography (CT), and blood test results in each wave. Patients were further classified into respiratory failure and nonrespiratory failure groups and statistically compared. Results Of the 565 patients diagnosed with COVID-19, 546 were included in this study. The percentage of patients classified as mild was approximately 10% in the 4th and 5th waves, but the rate increased after the 6th wave, with rates of 55.7% and 54.8% in each wave. Although more than 80% of patients in the 4th and 5th waves showed pneumonia on chest CT, the percentage decreased to approximately 40% after the 6th wave. Further comparisons between the respiratory failure group (n=75) and the nonrespiratory failure group (n=471) revealed significant differences in the age, sex, vaccination history, and biomarker values between the two groups. Conclusion In this study, elderly men were found to be more likely to develop severe disease than others, and biomarkers of COVID-19, such as C-reactive protein and lactate dehydrogenase, were useful for predicting severity. This study also suggested that vaccination may have contributed to a reduced disease severity.

Invasion of small cell lung cancer into the limbic system from leptomeningeal metastases.

The diagnosis of leptomeningeal metastases is sometimes difficult when the cytology of cerebrospinal fluid is negative. We report a rare case of leptomeningeal metastases that required differentiation from paraneoplastic limbic encephalitis. A 67-year-old man with extensive-stage small cell lung cancer was admitted for a sudden decrease in the level of consciousness. He suffered memory disturbances that began the day before admission. Diffusion-weighted and fluid-attenuated inversion recovery images of brain magnetic resonance imaging (MRI) showed bilateral symmetric areas of hyperintensity in the hippocampus, amygdala, insular cortex, and medial temporal lobe; contrast enhancement was positive. Cytology of the cerebrospinal fluid (CSF) was negative. Anti-N-methyl-d-aspartate receptor antibody and herpes simplex virus DNA were not detected in the CSF. Paraneoplastic Limbic encephalitis was suspected due to his symptoms and brain MRI scan. The patient developed generalized seizures after admission. High-dose methylprednisolone and intravenous immune globulin were administered, but his condition did not improve. Uncontrollable seizures persisted and he died in the hospital at day 13. Autopsy revealed leptomeningeal metastasis and invasion of cancer cells into the limbic system. Contrast-enhanced MRI should be performed even if limbic encephalitis is suspected, and leptomeningeal metastases should be suspected if the lesions are enhanced.