Objective Chronic hepatitis C virus (HCV) infection carries a residual risk of hepatocarcinogenesis even after viral elimination, so appropriate follow-up is necessary. The present study investigated the current hospital visits and hepatocarcinogenesis status of patients who received daclatasvir plus asunaprevir treatment (DCV+ASV) to determine whether or not appropriate follow-up was being performed.

Methods We retrospectively analyzed hepatocarcinogenesis, the overall survival, and the length of hospital visits in 442 patients who applied for the medical expense subsidy system for viral hepatitis and received DCV+ASV treatment in Gunma Prefecture between October 2014 and December 2015. This also included 61 patients who had a history of hepatocellular carcinoma (HCC).

Results Among 442 patients, 388 achieved a sustained viral response (SVR) by DCV+ASV therapy (87.8%), and 95.9% achieved an SVR if additional treatment was included. HCC was found in 75 cases (17.0%). A history of HCC, the FIB-4 index and the treatment effect SVR were determined to be factors affecting the incidence of HCC. Regarding the follow-up rate, 89.9% of patients continued to regularly visit the hospital after 5 years of treatment. However, patients ≤60 years old had significantly lower persistence rates than older patients. The persistence rate of hospital visits to the same institution was 67.7% over a 5-year period, which was significantly better in small and medium-sized institutions than in large, specialized institutions (71.7% vs. 63.9%, p=0.039).

Conclusion Patients with direct-acting antiviral treatment generally received adequate follow-up, but younger patients had a slightly higher rate of follow-up interruption and were considered to need support.

Objective Nocturnal desaturation is common in patients with chronic respiratory disease and often worsens the prognosis. Therefore, it should be diagnosed accurately and appropriately treated. The aim of this study was to clarify the diversity of nocturnal desaturation.

Methods We prospectively enrolled 58 outpatients diagnosed with chronic respiratory disease receiving home oxygen therapy and measured nocturnal SpO₂ using a portable oximeter. We classified nocturnal desaturation (3% decrease in SpO₂ from baseline) into three patterns: periodic pattern (desaturation duration of <655 seconds), sustained pattern (desaturation duration of ≥655 seconds), and intermittent pattern (desaturation and recovery of SpO₂ repeated with a cycle of several minutes).

Results Nocturnal hypoxemia (SpO₂≤88% for more than 5 minutes) was found in 23.8% of patients. The percentage of patients with chronic obstructive pulmonary disease (COPD) was significantly higher in the nocturnal hypoxemia group than in the non-hypoxemia group (80% vs. 40.6%, p=0.03). Desaturation with a periodic pattern was found in 81% of patients, desaturation with a sustained pattern was found in 40.5% of patients, and desaturation with an intermittent pattern was found in 59.5% of patients. In patients with COPD, desaturation with a periodic pattern was found in 85.7%, desaturation with a sustained pattern was found in 47.6%, and desaturation with an intermittent pattern was found in 57.1%.

Conclusion The SpO₂ waveform of nocturnal hypoxemia was able to be classified into three patterns. Suitable treatment for each pattern might improve the prognosis of these patients.

Objective This study aimed to elucidate the effects of early macrolide administration on genetically confirmed pertussis-induced cough in adolescents and adults.

Methods This single-center, retrospective cohort study examined the effects of the early administration of macrolides and antitussive agents on cough secondary to pertussis. We divided the patients into two groups based on the median duration from the beginning of the cough to the initiation of macrolide administration: early macrolide administration group (EMAG) and non-early macrolide administration group (NEMAG). The clinical improvement of cough was defined as maintaining a cough awareness score of ≤3 points for 3 consecutive days.

Patients The medical records of 40 patients diagnosed with pertussis (≥12 years old) who were able to maintain a cough diary and received no other antibiotics aside from macrolides were included in the study. A diagnosis of pertussis was made using the loop-mediated isothermal amplification (LAMP) test.

Results The EMAG (24 patients) showed a significantly shorter total cough period than the NEMAG [16 patients; 20.0 (95% confidence interval (CI), 16-28) vs. 30.5 (95% CI, 27-40) days; log-rank test, p=0.002]. There was no significant difference in the post-administration cough periods between the EMAG and NEMAG [11.0 (95% CI, 7-19) vs. 13.0 (95% CI, 5-23) days; log-rank test, p=0.232]. Antitussive agents did not affect the cough.

Conclusion The early administration of macrolides, but not antitussive agents, is effective for treating pertussis. Therefore, macrolides should be administered as soon as possible for this disease.

Objective Due to the lack of specific clinical manifestations and symptoms, it is difficult to distinguish COVID-19 from mimics. A common pitfall is to rush to make a diagnosis when encountering a patient with COVID-19-like symptoms. The present study describes a series of COVID-19 mimics using an outpatient database collected from a designated COVID-19 healthcare facility in Tokyo, Japan.

Methods We established an emergency room (ER) tailored specifically for patients with suspected or confirmed COVID-19 called the "COVID-ER." In this single-center retrospective cohort study, we enrolled patients who visited the COVID-ER from February 1 to September 5, 2020. The outcomes included the prevalence of COVID-19, admission, potentially fatal diseases and final diagnosis.

Results We identified 2,555 eligible patients. The median age was 38 (interquartile range, 26-57) years old. During the study period, the prevalence of COVID-19 was 17.9% (457/2,555). Non-COVID-19 diagnoses accounted for 82.1% of all cases. The common cold had the highest prevalence and accounted for 33.0% of all final diagnoses, followed by gastroenteritis (9.4%), urinary tract infections (3.8%), tonsillitis (2.9%), heat stroke (2.6%) and bacterial pneumonia (2.1%). The prevalence of potentially fatal diseases was 14.2% (298/2,098) among non-COVID-19 patients.

Conclusion Several potentially fatal diseases remain masked among the wave of COVID-19 mimics. It is imperative that a thorough differential diagnostic panel be considered prior to the rendering of a COVID-19 diagnosis.

Objective Tsushima mamushi (Gloydius tsushimaensis) is an endemic species of snake inhabiting only Tsushima Island, a remote Japanese island. We conducted a multicenter, retrospective study of G. tsushimaensis bites for the first time and developed a treatment algorithm that unified treatment on the island and is still in use today.

Methods This is a multicenter, retrospective study comparing 72 cases from January 2005 to December 2018, before the introduction of the algorithm, and 12 cases from January 2019 to December 2020, after its introduction.

Results There was no significant decrease in the maximum grade of symptoms after the introduction of the algorithm, but there was a decreasing trend (p=0.057). Conversely, the median of the maximum creatinine kinase levels was 343.5 IU/L (interquartile range: 115.5-4,745.5) before the algorithm's introduction and significantly lower (142.5; interquartile range: 111.3-163) after the algorithm's introduction (p=0.042). After the algorithm's introduction, the disseminated intravascular coagulation merger rate and the acute kidney injury incidence both dropped to 0%, from 9.7% and 6.9%, respectively, before the algorithm's introduction. There was no significant difference in the length of hospital stay before versus after the algorithm's introduction.

Conclusion This study showed that the treatment algorithm can be safely and quickly applied. The algorithm's effectiveness is expected to be strengthened by the accumulation of more cases in the future.

We herein report the first case of low-dose oxygen therapy for pneumatosis cystoides intestinalis (PCI) using PaO₂ as a therapeutic index to prevent acute exacerbation of interstitial pneumonia. An 86-year-old man was admitted to our hospital with abdominal distension. PCI was diagnosed by abdominal computed tomography. Low-dose oxygen therapy was started to avoid acute exacerbation of interstitial pneumonia. The oxygen dose was adjusted so that the PaO₂ value was approximately 100 mmHg. After seven days of treatment, the colon gas had disappeared, and no acute exacerbation of interstitial pneumonia was observed. A PaO₂ value around 100 mmHg is effective for PCI without inducing acute exacerbation of interstitial pneumonia.

We report a case of anorexia nervosa (AN) with gastroesophageal varices (GEV) in a 36-year-old woman. The patient presented to our hospital with progressive bloating due to severe ascites. She had no history of alcohol intake. Esophagogastroduodenoscopy and enhanced computed tomography revealed GEV and multiple hepatic nodules, respectively. The histological examination of a liver biopsy specimen revealed similar features to nonalcoholic fatty liver disease and showed hyperplastic nodules that were suspected to be related to the uneven distribution of portal blood flow in the liver. In conclusion, patients with long-term AN should undergo abdominal imaging to detect signs of portal hypertension.

A 41-year-old man was admitted with a chief complaint of dyspnea. Echocardiography showed diffuse severe hypokinesis in the left ventricle. Although his heart failure improved, high creatine kinase levels persisted. A muscle biopsy of the biceps brachii showed necrotic and regenerating fibers along with positive findings for major histocompatibility complex class I and membrane attack complex. He was diagnosed with antibody-negative immune-mediated necrotizing myopathy (IMNM). Steroid therapy was started, but he died due to ventricular fibrillation. Autopsy findings revealed CD68-positive macrophages in the myocardium and quadriceps. To our knowledge, this is the first case of antibody-negative IMNM with cardiac involvement.

Acute type A aortic dissection is a potentially fatal disease, and emergency surgery should be considered when it is diagnosed. We herein report two cases of retrograde type A aortic dissection with intramural hematoma, followed by re-dissection, rupture, and cardiac tamponade. The diagnoses in these cases had to be made carefully, as the false lumen of the ascending aorta was sometimes unclear on contrast-enhanced computed tomography.

Membranous nephropathy often achieves spontaneous remission. However, there are scarce reports of spontaneous remission of thrombospondin type-1 domain-containing 7A (THSD7A)-associated membranous nephropathy. A 64-year-old female presented with nephrotic syndrome and edema of the lower extremities. We diagnosed membranous nephropathy by kidney biopsy and confirmed positive THSD7A on immunofluorescence using frozen sections; serum THSD7A antibodies were also detected. Thirty-four months after the initial diagnosis, she achieved a spontaneous complete remission without immunosuppressive therapy. With the complete remission, no serum THSD7A levels were detected. In this study, we describe serial examinations of kidney biopsies and serum THSD7A antibodies.

Tubulointerstitial nephritis (TIN) with IgM-positive plasma cells (IgMPC-TIN) is an autoimmune kidney disease characterized by IgM/CD138-double-positive plasma cell infiltration in the tubulointerstitium. A 50-year-old man developed IgMPC-TIN and presented with crystalline inclusions in the rough endoplasmic reticulum. Intracellular crystal formation is a rare finding in paraprotein-related kidney diseases, but this case showed no pathogenic monoclonal immunoglobulin. Prednisolone (PSL, 30 mg) improved the TIN, but PSL tapering resulted in the recurrence of TIN. Combination therapy with 15 mg PSL and 150 mg mizoribine ultimately stabilized TIN. This case offers original evidence concerning the pathophysiology and treatment strategy of IgMPC-TIN.

Good's syndrome is associated with thymoma and acquired immunodeficiency. A 54-year-old man visited our hospital with a complaint of cough. Chest imaging revealed diffuse nodular shadows and anterior mediastinal mass. Hypogammaglobulinemia and a decreased B lymphocyte count were found by a laboratory evaluation. The lung nodules markedly regressed after immunoglobulin therapy. The mediastinal mass and remaining nodule were surgically resected and diagnosed as a type AB thymoma and a necrotizing epithelioid granuloma with T lymphocyte-dominant alveolitis, respectively. The overall appearances of these lesions were mostly in line with the spectrum of granulomatous-lymphocytic interstitial lung disease associated with Good's syndrome.

A 94-year-old woman with rheumatoid arthritis who had been treated with low-dose methotrexate was referred to our hospital because of a 3-day history of a fever and pancytopenia. With a diagnosis of febrile neutropenia of unknown origin, empirical antibiotic treatment and folinic acid therapy were initiated. Despite a recovery from pancytopenia, the high fever remained, and dyspnea developed. She was clinically diagnosed with Pneumocystis jirovecii pneumonia (PCP) and successfully treated with trimethoprim/sulfamethoxazole and adjunctive corticosteroid therapy. Folinic acid treatment effectively brought about rapid immune recovery but might have led to a clinical manifestation of PCP resembling immune reconstruction inflammatory syndrome.

We herein report a rare case of BCR-ABL1-positive B-lymphoblastic lymphoma (B-LBL). An 18-year-old woman had a history of persistent left-sided chest pain. Positron emission tomography showed increased metabolic activity in the fifth rib, duodenum, and pancreas. The pathological findings of the pancreas, duodenum, and bone marrow confirmed the diagnosis of B-LBL. Polymerase chain reaction of duodenum and bone marrow also revealed a minor BCR-ABL1 fusion gene. She was diagnosed with BCR-ABL1-positive B-LBL and administered dasatinib and prednisolone. She achieved complete remission two weeks after the initiation of the treatment. She received stem cell transplantation after consolidation chemotherapy and sustained complete remission.

A 72-year-old man presented with chorea while undergoing treatment for recurrence of nodal peripheral T-cell lymphoma with T follicular helper (TFH) phenotype. An examination by brain N-isopropyl-p-iodoamphetamine (¹²³I-IMP)-single photon emission computed tomography (SPECT) revealed no abnormalities other than a decreased cerebral blood flow (CBF) in the left striatum. After four courses of salvage chemotherapy, his clinical symptoms and asymmetric cerebral perfusion improved, suggesting that the decreased CBF had caused chorea. The significance of brain SPECT has not been fully clarified in patients with chorea-associated malignant lymphoma, warranting further investigations. Brain SPECT is an alternative approach to identify abnormalities in such patients.

A 68-year-old man was admitted to our department because of left incomplete homonymous hemianopia accompanied by hyperglycemia. Both T2-weighted and diffusion-weighted imaging revealed a low signal intensity along the subcortex and high signal intensity along the cortex on the right parietal and occipital lobes. Furthermore, arterial spin labeling and single-photon emission computed tomography showed hyperperfusion at the right parieto-occipital lobe. However, the electroencephalography result was normal. Hyperperfusion improved after controlling the blood glucose levels; nevertheless, homonymous hemianopia remained. We suspect that the irreversible brain damage was attributable to hyperperfusion associated with long-term hyperglycemia.

We herein report a 49-year-old man with a fever, diagnosed with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. After two weeks of hospitalization, he suddenly mentioned visual field impairment. Computed tomography and magnetic resonance imaging revealed white matter damage and vasogenic edema. Cerebrospinal fluid showed increased levels of interleukin (IL)-6. His symptoms and white matter lesion deteriorated. After treatment with intravenous methylprednisolone therapy and plasmapheresis, his symptoms and white matter lesion improved gradually. We suspect that our patient was affected by a secondary hyperinflammatory syndrome related to cytokines, alone or in combination with direct viral injury through endothelial cell damage. The IL-6 levels were elevated only in the cerebrospinal fluid, suggesting focal central nervous system inflammation.

Localized Listeria infection predominantly occurs in the prosthetic and hip joints. We herein report a case of Listeria monocytogenes ankle osteomyelitis in a 73-year-old man receiving adalimumab who was transferred to our hospital because of suspected rheumatoid arthritis (RA) flare. He reported a four-month history of left ankle swelling. A surgical biopsy revealed L. monocytogenes osteomyelitis in the left tibia and talus bones. The patient was successfully treated with antibiotics and surgical debridement. Thus, infection due to L. monocytogenes can present as ankle osteomyelitis in immunocompromised patients and may mimic an RA flare.