Background: Effect of meteorological factors such as air temperature, humidity, and sunlight exposure on transmission dynamics of novel coronavirus disease 2019 (COVID-19) remains controversial. We investigated the association of these factors on COVID-19 incidence in Japan. Methods: We analyzed data on reverse transcription polymerase chain reaction confirmed COVID-19 cases for each prefecture (total=47) in Japan and incidence rate was defined as the number of all reported cumulative cases from January 15 to March 17, 2020. Independent variables of each prefecture included three climatic variables (mean values of air temperature, relative humidity, and sunlight exposure), population elderly ratio, and the number of inbound travelers from China during February 2020. Multivariable-adjusted Poisson regression model was constructed to estimate COVID-19 incidence rate ratio (IRR) of independent variables. Results: There was a total of 702 cases during the study period in Japan (population=125, 900,000). Mean±standard deviation values of meteorological variables were 7.12°C±2.91°C for air temperature, 67.49%±7.63% for relative humidity, and 46.77±12.55% for sunlight exposure. Poisson regression model adjusted for climate variables showed significant association between the incidence and three climatic variables: IRR for air temperature 0.854 (95% confidence interval [CI], 0.804–0.907; P<0.0001), relative humidity 0.904 (95% CI, 0.864–0.945; P<0.0001), and sunlight exposure 0.973 (95% CI, 0.951–0.997; P=0.026). Conclusion Higher values of air temperature, relative humidity and sunlight exposure were associated with lower incidence of COVID-19. Public health interventions against COVID-19 epidemic in a country should be developed by considering these meteorological factors.

Coronavirus disease 2019 (COVID-19) is a highly infectious disease that has caused a pandemic devastating many countries worldwide. It is a complex and multifaceted disease with a unique coronavirus etiology, pathogenesis, zoonotic, and human-to-human transmission, causing acute respiratory distress syndrome with high mortality. Accurate and timely diagnosis is of utmost importance. In this study, we discussed the complexities of COVID-19 diagnostic elements in the context of pandemicity, drawing from our awareness, observations, and lessons learned from two previous coronavirus pandemics, namely SARS-CoV (severe acute respiratory syndrome coronavirus) in 2002 and MERS-CoV (Middle East respiratory syndrome-related coronavirus) in 2012, and how they applied to the diagnosis of COVID-19 today. Diagnosis of COVID-19 takes place without physician-patient personal contact due to isolation or quarantine or in the hospital setting, emergency units, and critical care units with the cumbersome barriers of personal protective equipment. Technical diagnosis is important, but we also emphasized the human impact of diagnosing COVID-19. Conveying the diagnosis of a critical disease to patients and families requires aspects of excellence in professionalism: ethics, empathy, and humility. Diagnostic skills in COVID-19 should extend to prognostication for patients suffering at the end of life, so that they will not be deprived of high-quality palliative care and comfort.

In this case report, we describe a male patient with subacute thyroiditis with severe paresthesia in a glove-and-stocking type distribution and thyroid gland tenderness but with minimal symptoms of hyperthyroidism. His paresthesia improved and then disappeared within several days after low dose oral prednisolone was initiated. As possible mechanisms for his severe paresthesia, we propose the following: 1) thyrotoxic effect on the peripheral nerves, and 2) generalized inflammatory effect on the peripheral nerves akin to that in the thyroid gland. Subacute thyroiditis may need to be considered as one of differential diagnoses for severe paresthesia.

Background: At present clinical reasoning skills are not systematically taught in Japanese medical universities. We developed a prototypic preliminary module for clinical tutors to introduce clinical reasoning to Japanese medical students. We hypothesized that tutored medical students would outperform self-study students.
Method: Using the web-based Sequential Question and Answer test that rewarded history and differential diagnosis as proxies for clinical reasoning, we compared the pre and posttest scores of 12 randomized fifth grade tutored students at two universities during four tutor-led 1.5-hour web-based seminars using a structured syllabus to 12 randomized self-study students.
Results: The tutored and self-study groups’ pretest scores were statistically similar at about 40 out of 100 weighted correct points. The tutored students’ posttest scores were 62 points, significantly greater (p = 0.007) than the pretest mean 42 points, compared to the self-study students’ posttest scores of 52 points, significantly greater (p = 0.012) than pretest mean 40 points. The difference between the two posttest groups was of borderline statistical significance (p = 0.08).
Conclusions: We successfully assessed a prototypic module for tutors to introduce clinical reasoning to Japanese medical students. The tutored students achieved higher scores than the self-study students. Further research is needed to exploit the potential of our modular clinical reasoning system.

Obsessive-compulsive disorder (OCD) is characterized by multiple obsessions and compulsions. A 22 years old woman who had mental traumatic event started having laryngopharyngeal discomfort, short term mental disturbance, and urge of repetitive checking of home door, spelling, and calculations of simple arithmetic. There was no evidence of organic causes. The diagnosis of OCD was established by meeting DSM-V criteria, and cognitive behavioral therapy was started. We report this case since it is important to consider the possibility of OCD for patients with unexplained somatic symptoms as well as unusual behavioral symptoms.

Background: New onset fever is a common symptom among hospitalized patients and it may be a manifestation of fatal illnesses such as infection. However, its epidemiology and predictors for mortality have not been fully determined in a Japanese teaching hospital.
Methods: We investigated adult patients with new onset elevated temperature of 37.5 degrees Celsius or greater the 3^rd day after admission during a 4-month study period. Only the first, single episode per patient was analyzed. We determined the causes of fever among these patients with new onset fever. We also analyzed predictors for in-hospital mortality among these patients. These predictors were based on multivariable adjusted logistic regression using demographics, vital signs at the time of fever onset, baseline diseases, and basic laboratory data.
Results: From a total of 2,271 admitted patients, 126 patients (5.6%) developed fever. Among these febrile patients, 98 (78%) had infectious diseases with a prevalence of 4.3% in all admitted patients. The most common cause of infection among those patients was respiratory tract infection, followed by urinary tract infection. Causes for non-infectious fever included neoplastic diseases, inflammatory diseases, and drug fever. In-hospital mortality was associated with lower mean blood pressure <60 mmHg with odds ratio (OR) of 12.7 (95% CI, 1.3–121), tachycardia >90/min with OR 4.1 (95% CI, 1.2–13.5), tachypnea >20/min with OR 10.0 (95% CI, 2.8–35.2), and neoplastic disease with OR 4.1 (95% CI, 1.3–13.1). Infection as a cause of fever was not associated with mortality.
Conclusion: The majority of inpatients with new onset fever had infectious diseases, however fever was also caused by neoplastic diseases, inflammatory diseases and drug fever. Abnormality of vital signs and neoplastic disease were related to in-hospital mortality.

We report on a case of the altered mental status from hyperammonemia due to a urinary tract infection of urease-producing (urea-splitting) bacteria. A 98-year-old Japanese woman, who had no history of liver cirrhosis or portal hypertension, presented with altered mental status. The cause of the altered mental status was attributed to an elevation of ammonia in her blood. The urine culture grew Proteus vulgaris. Complete recovery occurred with the use of an antibiotic for the urinary tract infection. Among patients with urinary tract infections, but without liver cirrhosis or portal hypertension, production by urea-splitting bacteria and the subsequent tubular reabsorption of ammonia, may result in hyperammonemic encephalopathy.