Fatal Myopericarditis Following an Influenza A (H3N2) Infection

Postinfluenza Cardiac Tamponade: A Review of Published Case Reports

Increased vaccination rates and better understanding of influenza virus infection and clinical presentation have improved the disease's overall prognosis. However, influenza can cause life-threatening complications such as cardiac tamponade, which has only been documented in case reports. We searched PubMed/Medline and SCOPUS and EMBASE through December 2021 and identified 25 case reports on echocardiographically confirmed cardiac tamponade in our review of influenza-associated cardiac tamponade. Demographics, clinical presentation, investigations, management, and outcomes were analyzed using descriptive statistics. Among 25 cases reports [19 adults (47.6 ±15.12) and 6 pediatric (10.1 ± 4.5)], 15 (60%) were females and 10 (40%) were male patients. From flu infection to the occurrence of cardiac tamponade, the average duration was 7±8.5 days. Fever (64%), weakness (40%), dyspnea (24%), cough (32%), and chest pain (32%) were the most prevalent symptoms. Hypertension, diabetes, and renal failure were most commonly encountered comorbidities. Sinus tachycardia (11 cases, 44%) and ST-segment elevation (7 cases, 28%) were the most common ECG findings. Fourteen cases (56%) reported complications, the most common being hypotension (24%), cardiac arrest (16%), and acute kidney injury (8%). Mechanical circulatory/respiratory support was required for 14 cases (56%), the most common being intubation (9 cases, 64%). Outcomes included recovery in 88% and death in 3 cases. With improving vaccination rates, pericardial tamponade remains an infrequently encountered complication following influenza virus infection. The complicated cases appear within the first week of diagnosis, of which nearly half suffer from concurrent complications including cardiac arrest or acute kidney injury. Majority of patients recovered with timely diagnoses and therapeutic interventions.

Influenza Myopericarditis and Pericarditis: A Literature Review

Myopericarditis is a rare complication of influenza infection. The presentation may range from mild and frequently unrecognized, to fulminant and potentially complicated by cardiogenic and/or obstructive shock (tamponade), which is associated with high mortality. We performed a review of literature on all influenza pericarditis and myopericarditis cases according to PRISMA guidelines using the PubMed search engine of the Medline database. Seventy-five cases of influenza myopericarditis and isolated pericarditis were identified from 1951 to 2021. Influenza A was reported twice as often as influenza B; however, influenza type did not correlate with outcome. Men and elderly patients were more likely to have isolated pericarditis, while women and younger patients were more likely to have myopericarditis. All included patients had pericardial effusion, while 36% had tamponade. Tamponade was more common in those with isolated pericarditis (41.2%) than myopericarditis (13.8%). Cardiogenic shock was more common in patients with myopericarditis (64%), with an overall mortality rate of 14.7%. Nearly 88% of the recovered patients remained without long-term complications reported. Conclusion: Influenza A appears a more common cause of pericarditis and myopericarditis. Isolated pericarditis was more commonly associated with tamponade but without reported deaths, whereas myopericarditis was more commonly associated with cardiogenic shock and death (19%).

Heart failure among patients admitted with Influenza. The influenza subtypes, seasonality and mortality: A case series

Respiratory infections like influenza infections have been found to increase the risk of coronary artery disease and precipitate cardiac failure. However, Indian data is lacking. A retrospective observational study was done to describe patients with influenza infection who had concomitant heart failure (HF) requiring admission over 5 years (January 2013-December 2017). A total of 93 influenza cases were hospitalised during this time, of which 14 (15%) also had features of HF. Among them, the types of influenza infection were AH1N1 (6,43%), BH1N1 (4,29%), AH3N2 (3,21%) with one patient having both strains. Two-thirds of the HF were new onset (10, 71%), whereas rest were due to acute worsening of pre-existing HF (4, 29%). Ten (64.3%) of the patients had HF with reduced ejection fraction (HFrEF). The average hospital stay was 10 days with 2 (14%) deaths. The peak of influenza in August and September preceded the peak admission for HF. A total of 15% of influenza admissions have concomitant HF. They are predominantly due to influenza A H1N1 (43%), influenza A H3N2 (21%) and influenza B (29%). Only 7% had preceding influenza vaccination. Influenza during August and September appears to precede the peak of HF admissions which happen in October and November. Overall mortality was 14%

New sesquiterpeniod esters form Blumea balsamifera (L.) DC. and their anti-influenza virus activity

Phytochemical studies led to the isolation of five new sesquiterpeniod esters, named balsamiferine N-R, along with ten known compounds (6-15) from the leaves of Blumea balsamifera (L.) DC. The skeletons of nine known sesquiterpeniods belong to guaiane and eudesmane. The structures of the new compounds including their absolute configurations were elucidated by comprehensive spectroscopic analysis, and quantum-chemical electronic circular dichroism (ECD) calculation. Compounds 3 and 4 showed significant inhibitory effects on influenza A virus (H3N2) with IC₅₀ values of 46.23 μg/mL and 38.49 μg/mL, respectively. It was the first report on the anti-influenza A virus constituents from B. balsamifera.

Improving immunological insights into the ferret model of human viral infectious disease

Ferrets are a well‐established model for studying both the pathogenesis and transmission of human respiratory viruses and evaluation of antiviral vaccines. Advanced immunological studies would add substantial value to the ferret models of disease but are hindered by the low number of ferret‐reactive reagents available for flow cytometry and immunohistochemistry. Nevertheless, progress has been made to understand immune responses in the ferret model with a limited set of ferret‐specific reagents and assays. This review examines current immunological insights gained from the ferret model across relevant human respiratory diseases, with a focus on influenza viruses. We highlight key knowledge gaps that need to be bridged to advance the utility of ferrets for immunological studies.

A paediatric influenza update 100 years after the Skyros island Spanish flu outbreak

This year marks the 100th anniversary of the 1918 Spanish flu outbreak on the Greek Aegean Sea island of Skyros, which devastated its population in less than 30 days. According to Constantinos Faltaits's annals published in 1919, the influenza attack on the island of Skyros commenced acutely ‘like a thunderbolt’ on the 27th of October, 1918 and was exceptionally severe and fatal. At that time, the viral cause of the influenza had not been detected, while the total number of victims of the Spanish flu outbreak has been estimated to have surpassed 50 million, worldwide. Almost one century after this Aegean Sea island's tragedy, the ‘4th Workshop on Paediatric Virology’, organised on the 22nd of September, 2018 in Athens, Greece, was dedicated to the 100 years of the ‘Spanish’ flu pandemic. This review article highlights the plenary and key lectures presented at the workshop on the recent advances on the epidemiology, clinical management and prevention of influenza in childhood.