Effectiveness of mRNA COVID-19 vaccines against symptomatic SARS-CoV-2 infections during the SARS-CoV-2 Omicron BA.1 and BA.2 epidemic in Japan: vaccine effectiveness real-time surveillance for SARS-CoV-2 (VERSUS)

Background: Evaluating COVID-19 vaccine effectiveness (VE) domestically is crucial for assessing and determining national vaccination policy. This study aimed to evaluate VE of mRNA COVID-19 vaccines in Japan. Methods: We conducted a multicenter test-negative case-control study. The study comprised indivi-duals aged ≥16 visiting medical facilities with COVID-19-related signs or symptoms from 1 January to 26 June 2022, when Omicron BA.1 and BA.2 were dominant nationwide. We evaluated VE of primary and booster vaccination against symptomatic SARS-CoV-2 infections and relative VE of booster compared with primary.Results: We enrolled 7,931 episodes, including 3,055 test positive. The median age was 39, 48.0% were male, and 20.5% had underlying medical conditions. In individuals aged 16 to 64, VE of primary vaccination within 90 days was 35.6% (95% CI, 19.0–48.8%). After booster, VE increased to 68.7% (60.6–75.1%). In individuals aged ≥65, VE of primary and booster was 31.2% (−44.0–67.1%) and 76.5% (46.7–89.7%), respectively. Relative VE of booster compared with primary vaccination was 52.9% (41.0– 62.5%) in individuals aged 16 to 64 and 65.9% (35.7–81.9%) in individuals aged ≥65.Conclusions: During BA.1 and BA.2 epidemic in Japan, mRNA COVID-19 primary vaccination provided modest protection. Booster vaccination was necessary to protect against symptomatic infections

Native valve endocarditis due to Escherichia coli infection: a case report and review of the literature

Abstract Background Infective endocarditis due to Escherichia coli is a rare disease but is increasing in frequency, especially among older women. In addition, its mortality rate is higher than that of endocarditis due to the HACEK-group gram-negative bacteria (Haemophilus spp., Aggregatibacter spp., Cardiobacterium hominis, Eikenella corrodens, and Kingela spp.). Case presentation A 58-year-old Japanese woman with a history of alcohol abuse was admitted to our hospital because of a fever. She was diagnosed with infective endocarditis due to E. coli based on repeated blood cultures and transthoracic echocardiography, which revealed vegetations attached to the anterior leaflet and chordae tendineae of the mitral valve. Despite administration of sulbactam/ampicillin and gentamycin, she developed purulent spondylitis during hospitalization and required treatment with meropenem administration for 6 weeks, leading to resolution of the endocarditis. She took oral levofloxacin for 2 months, and the spondylitis was completely cured 7 months after discharge. Conclusion Escherichia coli affects native valves without degenerative valvulopathy rather than prosthetic valves, especially in patients with risk factors such as an immunosuppressive status, excessive alcohol consumption, or treatment with hemodialysis. Peripheral embolization, congestive heart failure, and valve-ring abscesses are major complications of E. coli endocarditis; notably, infective myocarditis can also occur. The mortality and surgical intervention rates are 21% and 42%, respectively. Physicians should be cognizant of the necessity of surgical intervention when E. coli endocarditis is resistant to antibiotic therapy

Multiple spontaneous hemorrhages after commencing warfarin therapy

A 94 year-old Japanese woman with renal dysfunction was admitted to our hospital for congestive heart failure caused by atrial fibrillation with rapid ventricular response. Considering the risk of stroke, warfarin was commenced. However, she developed shock following brachial and retroperitoneal hemorrhage 4 days after starting warfarin despite not being over-anticoagulated. She recovered after receiving blood transfusion and intravenous vitamin K2. Bleeding during warfarin administration occurs more frequently in older individuals with lower glomerular filtration rates, especially within the first 30 days of warfarin treatment. Physicians should therefore check for unexpected bleeding after commencing warfarin and be prepared to reverse anticoagulation

Pneumatosis intestinalis with a benign clinical course: a report of two cases

Abstract Background Pneumatosis intestinalis (PI) is a rare condition characterized by the presence of gas within the gastrointestinal tract wall. Most cases of PI have a benign clinical course, although some have serious outcomes. Mechanical stress on or bacterial infection of the gastrointestinal tract wall may be responsible for the onset of PI, but the detailed mechanism of PI pathogenesis is still unclear. Here, we describe two Japanese patients presenting with benign PI. Case presentation Case 1, a 37-year-old previously healthy male patient, had a 1-week history of abdominal pain, and case 2, a 78-year-old female diabetic patient, had a 2-week history of voglibose treatment and abdominal pain. Intramural gas was mainly distributed in the colon in case 1 and in the small intestine in case 2. Interestingly, neither patient showed obvious inflammatory signs upon admission and recovered spontaneously with conservative treatment, including fasting and fluid infusion without antibiotics. Voglibose treatment was terminated in case 2. Recent studies have shown the presence of nonpathogenic bacteria, such as Clostridium spp., in PI lesions, which usually play an important role in modulating the tolerance of the gastrointestinal immune responses. The benign clinical course and spontaneous resolution of PI in these patients, without specific treatment, suggests that nonpathogenic indigenous bacteria in the gastrointestinal tract participate in the pathogenesis of PI. Conclusion In patients with benign PI, the absence of an inflammatory response and the spontaneous resolution of the disease without specific treatment suggest the participation of nonpathogenic indigenous bacteria of the gastrointestinal tract

Malignant Lymphoma in the Psoas Major Muscle

An 84-year-old Japanese man taking warfarin to prevent cerebral infarction secondary to atrial fibrillation was admitted to our hospital for evaluation of a painless right back mass. Magnetic resonance imaging (MRI) showed an oval-shaped mass in the right psoas major muscle. The mass showed high intensity on T1-, T2-, and diffusion-weighted imaging and mimicked an acute-phase hematoma. However, it showed no chronological changes typical of a hematoma, and MRI revealed enlargement of the mass 1 week after admission. Histopathological examination of a biopsy specimen revealed diffuse large B-cell lymphoma (DLBCL). Although skeletal muscle lymphoma is rare, physicians should be familiar with its MRI characteristics. In addition, determination of the lymphoma subtype has important implications for the treatment of skeletal muscle lymphoma because DLCBL may have an especially poor prognosis

Original Article ST segment elevation in secondary cardiac cancer: a case report and review of the literature

Abstract: Secondary cardiac cancer most frequently originates from primary lung cancer and most commonly occurs in the pericardium. On electrocardiographic examination, patients with secondary cardiac cancer occasionally show ST segment elevation that mimics acute coronary syndrome, despite the absence of coronary artery occlusion. We herein describe a rare case of secondary cardiac cancer that presented with ST segment elevation and review the literature regarding ST segment elevation caused by secondary cardiac cancer. A 73-year-old Japanese woman was admitted to the hospital with chest pain. Electrocardiography showed abnormal ST segment elevation in the precordial and lateral leads, suggestive of ST-elevation myocardial infarction. Emergency coronary angiography showed occlusion of the distal left anterior descending coronary artery (LAD), and plain old balloon angioplasty of the LAD was performed. The ST segment elevation initially resolved after angioplasty, but recurred after 7 days. Contrast-enhanced chest computed tomography showed primary lung cancer in the left lower lobe, pericardial metastasis, and myocardial metastasis in the intraventricular septum and posterolateral wall of the left ventricle. Histopathological examination of the lung cancer was not performed. Patients with ST segment elevation due to secondary cardiac cancer may have symptoms and electrocardiographic changes mimicking anteroseptal or lateral infarction without the development of abnormal Q waves. These findings are frequently associated with posterolateral or anteroseptal invasion by primary lung cancer and may indicate a poor prognosis. In conclusion, physicians should be aware that secondary cardiac cancer may present with symptoms and ST segment elevation mimicking acute coronary syndrome, indicating a poor prognosis

Spontaneous isolated dissection of the superior mesenteric artery and aneurysm formation resulting from segmental arterial mediolysis: a case report

Abstract Background Spontaneous isolated dissection of the superior mesenteric artery (SMA) can lead to bowel ischemia, aneurysm rupture, or even death. Studies have suggested that mechanical or hemodynamic stress on the vascular wall of the SMA may be a contributor, but its pathogenesis is unclear. Case presentation A 57-year-old Japanese man with a history of untreated hypertension and hyperuricemia was admitted to our hospital with the sudden onset of severe epigastric pain. Laboratory findings showed elevated white blood cell count and C-reactive protein, and contrast-enhanced computed tomography (CT) of the abdomen demonstrated arterial dissection with luminal stenosis and aneurysm formation at the distal portion of the SMA after the branching of the jejunal artery, and intravenous nicardipine was administered. The patient’s epigastric pain resolved spontaneously but recurred on day 6 of his hospital stay. Contrast-enhanced abdominal CT revealed an enlarged aneurysm with wall thinning. Because of the risk of aneurysm rupture, the decision was made to perform aneurysmectomy and bowel resection on day 6. Histologic examinations revealed two separate dissecting lesions: one latent and the other resulting in aneurysm formation. Both lesions showed characteristics of segmental arterial mediolysis (SAM) with lack of arterial media, absence of internal and external elastic laminae and intimal proliferation. Conclusions Histologic findings in the present case suggest that mechanical or hemodynamic stress on the vascular wall and SAM-related vascular vulnerability may concomitantly contribute to the onset of isolated SMA dissection