Influenza myocarditis and myositis: case presentation and review of the literature

Lesions and viral antigen distribution in bald eagles, red-tailed hawks, and great horned owls naturally infected with H5N1 clade 2.3.4.4b highly pathogenic avian influenza virus

An epidemic of highly pathogenic avian influenza (HPAI) began in North America in the winter of 2021. The introduced Eurasian H5N1 clade 2.3.4.4b virus subsequently reassorted with North American avian influenza strains. This postmortem study describes the lesions and influenza A virus antigen distribution in 3 species of raptors, including bald eagles (Haliaeetus leucocephalus, n = 6), red-tailed hawks (Buteo jamaicensis, n = 9), and great horned owls (Bubo virginianus, n = 8), naturally infected with this virus strain based on positive reverse transcriptase polymerase chain reaction and sequencing results from oropharyngeal swabs. The birds presented with severe neurologic signs and either died or were euthanized because of the severity of their clinical signs and suspected influenza virus infection. Gross lesions were uncommon and included forebrain hemorrhages in 2 eagles, myocarditis in 1 hawk, and multifocal pancreatic necrosis in 3 owls. Histological lesions were common and included encephalitis, myocarditis, multifocal pancreas necrosis, multifocal adrenal necrosis, histiocytic splenitis, and anterior uveitis in decreasing frequency. Influenza A viral antigen was detected in brain, heart, pancreas, adrenal gland, kidney, spleen, liver, and eye. In conclusion, bald eagles, red-tailed hawks, and great horned owls infected with the HPAI clade 2.3.4.4b virus strain and showing neurological signs of illness may develop severe or fatal disease with histologically detectable lesions in the brain that are frequently positive for viral antigen.

Role for advanced heart failure therapies in the management of influenza B-associated fulminant myocarditis with recovery

A woman presented to the emergency department for syncope after developing influenza-like symptoms. She tested positive for influenza B. The patient rapidly decompensated into cardiogenic shock over 2 days, requiring aggressive pharmacological therapy and temporary mechanical circulatory support. She made a full recovery. This case highlights the importance of early intervention, urgent transplant evaluation and guideline directed medical therapy in the treatment of fulminant myocarditis secondary to influenza B infection.

The Cardiovascular Manifestations of COVID-19

The Coronavirus 2019 (COVID-19) pandemic, caused by the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) virus, has resulted in unprecedented morbidity and mortality worldwide. While COVID-19 typically presents as viral pneumonia, cardiovascular manifestations such as acute coronary syndromes, arterial and venous thrombosis, acutely decompensated heart failure (HF), and arrhythmia are frequently observed. Many of these complications are associated with poorer outcomes, including death. Herein we review the relationship between cardiovascular risk factors and outcomes among patients with COVID-19, cardiovascular manifestations of COVID-19, and cardiovascular complications associated with COVID-19 vaccination.

Cardiovascular Complications of Viral Respiratory Infections and COVID-19

Viral respiratory infections (VRI) are the most prevalent type of infectious diseases and constitute one of the most common causes of contact with medical care. Regarding the pathophysiology of the cardiovascular system, VRI can not only exacerbate already existing chronic cardiovascular disease (such as coronary artery disease or heart failure) but also trigger new adverse events or complications (e.g., venous thromboembolism), the latter particularly in subjects with multimorbidity or disease-related immobilization. In the current paper, we provide a narrative review of diverse cardiovascular complications of VRI as well as summarize available data on the pathology of the circulatory system in the course of coronavirus disease 2019 (COVID-19).

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%).

Virus Infection and Systemic Inflammation: Lessons Learnt from COVID-19 and Beyond

Respiratory infections with newly emerging zoonotic viruses such as SARS-CoV-2, the etiological agent of COVID-19, often lead to the perturbation of the human innate and adaptive immune responses causing severe disease with high mortality. The responsible mechanisms are commonly virus-specific and often include either over-activated or delayed local interferon responses, which facilitate efficient viral replication in the primary target organ, systemic viral spread, and rapid onset of organ-specific and harmful inflammatory responses. Despite the distinct replication strategies, human infections with SARS-CoV-2 and highly pathogenic avian influenza viruses demonstrate remarkable similarities and differences regarding the mechanisms of immune induction, disease dynamics, as well as the long-term sequelae, which will be discussed in this review. In addition, we will highlight some important lessons about the effectiveness of antiviral and immunomodulatory therapeutic strategies that this pandemic has taught us.

Case report: the management for a gestational hypertensive woman with influenza A virus pneumonia and peripartum cardiomyopathy

Background

Peripartum cardiomyopathy (PPCM) is defined as an idiopathic cardiomyopathy occurring in the last month of pregnancy or the first 6 months postpartum without an identifiable cause. PPCM is suspected to be triggered by the generation of a cardiotoxic fragment of prolactin and the secretion of a potent antiangiogenic protein from the placental, but no single factor has been identified or defined as the underlying cause of the disease. Influenza virus can cause PPCM through immune-mediated response induced by proinflammatory cytokines from host immunity and endothelial cell dysfunction. We report a case in a parturient woman undergoing a cesarean delivery, who had influenza A pneumonia and PPCM.

Case presentation

A parturient woman at 40 weeks and 1 day of gestation who had experienced gestational hypertension accompanied by pulmonary edema developed hypotension after undergoing an emergency cesarean delivery. An elevation of N-terminal prohormone of brain natriuretic peptide (NT-proBNP) was noted, and echocardiography revealed a left ventricular ejection fraction of 20%. She underwent a nasopharyngeal swab test, in which influenza A antigen was positive. She was diagnosed as having PPCM and received anti-viral treatment. After antiviral treatment, hemodynamic dysfunction stabilized. We present and discuss the details of this event.

Conclusion

PPCM is a heart disease that is often overlooked by medical personnel. Rapid swab tests, serum creatine kinase measurement, and echocardiography are imperative diagnostic approaches for the timely recognition of virus-associated cardiomyopathy in peripartum women with influenza-like disease and worsening dyspnea, especially during the epidemic season. Prompt antiviral treatment should be considered, particularly after PPCM is diagnosed.

Supplementary information

The online version contains supplementary material available at 10.1186/s12884-022-04814-9.

The viral distribution and pathological characteristics of BALB/c mice infected with highly pathogenic Influenza H7N9 virus

Background

The highly pathogenic Influenza H7N9 virus is believed to cause multiple organ infections. However, there have been few systematic animal experiments demonstrating the virus distribution after H7N9 virus infection. The present study was carried out to investigate the viral distribution and pathological changes in the main organs of mice after experimental infection with highly pathogenic H7N9 virus.

Methods

Infection of mice with A/Guangdong/GZ8H002/2017(H7N9) virus was achieved via nasal inoculation. Mice were killed at 2, 3, and 7 days post infection. The other mice were used to observe their illness status and weight changes. Reverse transcription polymerase chain reaction and viral isolation were used to analyse the characteristics of viral invasion. The pathological changes of the main organs were observed using haematoxylin and eosin staining and immunohistochemistry.

Results

The weight of H7N9 virus-infected mice increased slightly in the first two days. However, the weight of the mice decreased sharply in the following days, by up to 20%. All the mice had died by the 8th day post infection and showed multiple organ injury. The emergence of viremia in mice was synchronous with lung infection. On the third day post infection, except in the brain, the virus could be isolated from all organs (lung, heart, kidney, liver, and spleen). On the seventh day post infection, the virus could be detected in all six organs. Brain infection was detected in all mice, and the viral titre in the heart, kidney, and spleen infection was high.

Conclusion

Acute diffuse lung injury was the initial pathogenesis in highly pathogenic H7N9 virus infection. In addition to lung infection and viremia, the highly pathogenic H7N9 virus could cause multiple organ infection and injury.

Myocarditis occurrence with cancer immunotherapy across indications in clinical trial and post-marketing data

Antibodies targeting the PD-1, PD-L1, and CTLA-4 immune checkpoint axis have been used in a variety of tumor types. They achieve anti-tumor activity through activating the patient’s own immune system to target immune response evading cancer cells. However, this unique mechanism of action may cause immune-related adverse events, irAEs. One of these irAEs is myocarditis which is associated with an alarming mortality rate. In this study we presented clinical cases of myocarditis from safety trial datasets submitted to the U.S. Food and Drug Administration, FDA. Additionally, we analyzed over fourteen million FDA Adverse Event Reporting System, FAERS, submissions. The statistical analysis of the FAERS data provided evidence of significantly increased reporting of myocarditis in patients administered immune checkpoint inhibitors alone, in combination with another immune checkpoint inhibitor, the kinase inhibitor axitinib, or chemotherapy, for all cancer types, when compared to patients administered chemotherapy. All combination therapies led to further increased reporting odds ratios of myocarditis. We further analyzed the occurrence of myocarditis by stratifying the reports into sub-cohorts based on specific cancer types and treatment/control groups in major cancer immunotherapy efficacy trials and confirmed the observed trend for each cohort.

Pathological and clinical effects of interleukin-6 on human myocarditis

BACKGROUND

Numerous basic studies have shown a relationship between interleukin-6 (IL-6) and the development or severity of myocarditis. However, there has been no study in which the effect of IL-6 levels in patients with myocarditis was evaluated.

METHODS

We enrolled control patients (n = 12) and consecutive patients with acute myocarditis (n = 13), including lymphocytic, eosinophilic, and giant cell myocarditis, and investigated the pathological and clinical effects of IL-6 on human myocarditis.

RESULTS

The serum IL-6 level in patients with myocarditis (16.7 [9.9, 103.8] pg/mL) was significantly higher than that in the control patients (1.4 [1.0, 1.9] pg/mL) (P<0.001). Immunohistochemical analysis showed that IL-6 was expressed in infiltrating inflammatory cells of endomyocardial biopsy samples from all patients with myocarditis. Moreover, the log-transformed value of serum IL-6 level showed significant positive correlations with serum creatine kinase (CK) level, CK-MB level, peak CK level, peak CK-MB level and C-reactive protein level (all P ≤ 0.005) and a negative correlation with the left ventricular (LV) ejection fraction (p = 0.014). We divided the patients with myocarditis into a low IL-6 group (9.9 [4.5, 14.2] pg/dL, n = 7) and a high IL-6 group (108.9 [51.1, 130.9] pg/dL, n = 6). The degree of infiltration of IL-6-expressing inflammatory cells in myocardial samples obtained from patients in the high IL-6 group was significantly more severe than that in samples obtained from patients in the low IL-6 group. Furthermore, patients in the high IL-6 group significantly more frequently received catecholamine therapy (P = 0.005), venoarterial extracorporeal membrane oxygenation (P = 0.029), and artificial respirator support (P = 0.021) in the acute phase of myocarditis.

CONCLUSION

The results suggest that there is a strong impact of IL-6 on cardiac injury and dysfunction in patients with myocarditis.

Rare complication of four extremity compartment syndrome requiring fasciotomy from influenza A viral myositis

Influenza A and B commonly cause benign respiratory disease in humans, but can cause more severe illness in high-risk populations. We report an unusual case of a previously healthy adult patient who presented with myositis and severe rhabdomyolysis secondary to influenza A infection that resulted in atraumatic compartment syndrome of all four extremities, each requiring emergent fasciotomy. The patient was subsequently managed with delayed primary closure and skin grafting in the operating room. Prompt recognition of this rare complication by the team resulted in no limb amputations. On his first follow-up appointment, 1 month after discharge, he had regained full functionality in both his hands and his feet were both close to 50% of baseline and improving with physical therapy.

Influenza Myocarditis: A Literature Review

Viral myocarditis is not uncommon but the role of the influenza virus in causing myocarditis is less studied. It is difficult to diagnose influenza myocarditis. Due to bacterial and viral co-infection during influenza outbreaks, it becomes more difficult to distinguish influenza myocarditis from other causes. Our article provides current information on influenza myocarditis. We did a literature search using appropriate terms and reviewed articles published by November 2020. Our study highlights the incidence of influenza myocarditis and the need to become aware of this condition, especially during epidemics and pandemics. Our study highlights that although influenza myocarditis is a rare condition, it can be fatal. There should be increased awareness about the condition. By the early diagnosis and treatment of influenza myocarditis, we can prevent fatal complications.

Myopericarditis and myositis in a patient with COVID-19: a case report

BACKGROUND

Concurrent myopericarditis and myositis can present in patients with pre-existing systemic inflammatory diseases. Here we present a case of myopericarditis and myositis associated with COVID-19, in the absence of respiratory symptoms.

CASE SUMMARY

We present a middle-aged female with a history of hypertension and previous myopericarditis. The patient was admitted with symptoms of central chest pain, and ECG and echocardiographic features of myopericarditis. Her symptoms did not improve, and CT thorax suggested possible SARS-CoV-2 infection for which she tested positive, despite no respiratory symptoms. Whilst on the ward, she developed bilateral leg weakness and a raised creatine kinase (CK), and magnetic resonance imaging (MRI) of her thighs confirmed myositis. A cardiac MRI confirmed myopericarditis. She was treated with colchicine 500 μg twice daily, ibuprofen 400 mg three times day, and prednisolone 30 mg per day, and her symptoms and weakness improved.

DISCUSSION

We describe the first reported case of concurrent myopericarditis, and myositis associated with COVID-19. Conventional therapy with colchicine, non-steroidal anti-inflammatory drugs, and glucocorticoids improved her symptoms, and reduced biochemical markers of myocardial and skeletal muscle inflammation.

Acute Influenza B Infection Presenting as Cardiac Tamponade: A Case Report

Influenza A and B acute infections usually affect primarily the respiratory system. In rare cases, however, the cardiovascular system is also compromised either via the direct effect of the virus or via the worsening of preexisting cardiac conditions. We present a rare case of acute Influenza B infection presenting as pericardial effusion and cardiac tamponade.

A healthy 32-year-old female was presented to the emergency room with influenza-like symptoms for four days, where she was monitored for a few hours and was subsequently discharged to home after testing positive for Influenza B by polymerase chain reaction (PCR). On the fifth day, she returned to the emergency room with worsening symptoms, primarily exertional dyspnea. She was hypotensive and tachycardic and temporarily improved with fluid administration. She was transferred to the intensive care unit, where a bedside point of care ultrasound (POCUS) and later a formal transthoracic echocardiogram revealed that she had pericardial effusion with sonographic signs of cardiac tamponade. Emergent pericardiocentesis was performed and resulted in hemodynamic and symptomatic improvement. The pericardial drain that was initially left in place and continued to drain pericardial fluid (700 ccs in total), was removed 3 days later, after echocardiographic confirmation of the resolution of the pericardial effusion. She completed a five-day course of Oseltamivir and was subsequently discharged home safely.

In summary, our case describes an acute Influenza B infection that was complicated by pericardial effusion and cardiac tamponade. It also highlights the importance of bedside POCUS and echocardiography in the early diagnosis and treatment of cardiac tamponade cases, frequently with pericardiocentesis as in our case.

Myocarditis and inflammatory cardiomyopathy: current evidence and future directions

Inflammatory cardiomyopathy, characterized by inflammatory cell infiltration into the myocardium and a high risk of deteriorating cardiac function, has a heterogeneous aetiology. Inflammatory cardiomyopathy is predominantly mediated by viral infection, but can also be induced by bacterial, protozoal or fungal infections as well as a wide variety of toxic substances and drugs and systemic immune-mediated diseases. Despite extensive research, inflammatory cardiomyopathy complicated by left ventricular dysfunction, heart failure or arrhythmia is associated with a poor prognosis. At present, the reason why some patients recover without residual myocardial injury whereas others develop dilated cardiomyopathy is unclear. The relative roles of the pathogen, host genomics and environmental factors in disease progression and healing are still under discussion, including which viruses are active inducers and which are only bystanders. As a consequence, treatment strategies are not well established. In this Review, we summarize and evaluate the available evidence on the pathogenesis, diagnosis and treatment of myocarditis and inflammatory cardiomyopathy, with a special focus on virus-induced and virus-associated myocarditis. Furthermore, we identify knowledge gaps, appraise the available experimental models and propose future directions for the field. The current knowledge and open questions regarding the cardiovascular effects associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are also discussed. This Review is the result of scientific cooperation of members of the Heart Failure Association of the ESC, the Heart Failure Society of America and the Japanese Heart Failure Society.

Cardiac injury associated with severe disease or ICU admission and death in hospitalized patients with COVID-19: a meta-analysis and systematic review

BACKGROUND

Cardiac injury is now a common complication of coronavirus disease (COVID-19), but it remains unclear whether cardiac injury-related biomarkers can be independent predictors of mortality and severe disease development or intensive care unit (ICU) admission.

METHODS

Two investigators searched the PubMed, EMBASE, Cochrane Library, MEDLINE, Chinese National Knowledge Infrastructure (CNKI), Wanfang, MedRxiv, and ChinaXiv databases for articles published through March 30, 2020. Retrospective studies assessing the relationship between the prognosis of COVID-19 patients and levels of troponin I (TnI) and other cardiac injury biomarkers (creatine kinase [CK], CK myocardial band [CK-MB], lactate dehydrogenase [LDH], and interleukin-6 [IL-6]) were included. The data were extracted independently by two investigators.

RESULTS

The analysis included 23 studies with 4631 total individuals. The proportions of severe disease, ICU admission, or death among patients with non-elevated TnI (or troponin T [TnT]), and those with elevated TnI (or TnT) were 12.0% and 64.5%, 11.8% and 56.0%, and 8.2% and. 59.3%, respectively. Patients with elevated TnI levels had significantly higher risks of severe disease, ICU admission, and death (RR 5.57, 95% CI 3.04 to 10.22, P < 0.001; RR 6.20, 95% CI 2.52 to 15.29, P < 0.001; RR 5.64, 95% CI 2.69 to 11.83, P < 0.001). Patients with an elevated CK level were at significantly increased risk of severe disease or ICU admission (RR 1.98, 95% CI 1.50 to 2.61, P < 0.001). Patients with elevated CK-MB levels were at a higher risk of developing severe disease or requiring ICU admission (RR 3.24, 95% CI 1.66 to 6.34, P = 0.001). Patients with newly occurring arrhythmias were at higher risk of developing severe disease or requiring ICU admission (RR 13.09, 95% CI 7.00 to 24.47, P < 0.001). An elevated IL-6 level was associated with a higher risk of developing severe disease, requiring ICU admission, or death.

CONCLUSIONS

COVID-19 patients with elevated TnI levels are at significantly higher risk of severe disease, ICU admission, and death. Elevated CK, CK-MB, LDH, and IL-6 levels and emerging arrhythmia are associated with the development of severe disease and need for ICU admission, and the mortality is significantly higher in patients with elevated LDH and IL-6 levels.

Association Between Cardiac Injury and Mortality in Hospitalized Patients Infected With Avian Influenza A (H7N9) Virus

OBJECTIVES

To evaluate the prevalence of cardiac injury and its association with mortality in hospitalized patients infected with avian influenza A (H7N9) virus.

DESIGN

Retrospective cohort study.

SETTING

A total of 133 hospitals in 17 provinces, autonomous regions, and municipalities of mainland China that admitted influenza A (H7N9) virus-infected patients between January 22, 2015, and June 16, 2017.

PATIENTS

A total of 321 patients with influenza A (H7N9) virus infection were included in the final analysis.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Demographics and clinical characteristics were collected from medical records. Cardiac injury was defined according to cardiac biomarkers, electrocardiography, or echocardiography. Among the 321 patients, 203 (63.2%) showed evidence of cardiac injury. Compared with the uninjured group, the cardiac injury group had lower PaO2/FIO2 (median, 102.0 vs 148.4 mm Hg; p < 0.001), higher Acute Physiology and Chronic Health Evaluation II score (median, 17.0 vs 11.0; p < 0.001), longer stay in the ICU (10.0 vs 9.0 d; p = 0.029), and higher proportion of in-hospital death (64.0% vs 20.3%; p < 0.001). The proportion of virus clearance until discharge or death was lower in the cardiac injury group than in the uninjured group (58.6% vs 86.4%; p < 0.001). Multivariable-adjusted Cox proportional hazards regression analysis showed that cardiac injury was associated with higher mortality (hazards ratio, 2.06; 95% CI, 1.31-3.24) during hospitalization.

CONCLUSIONS

Cardiac injury is a frequent condition among hospitalized patients infected with influenza A (H7N9) virus, and it is associated with higher risk of mortality.

Severe myocarditis due to influenza A(H1N1)pdm09 viral infection in a young woman successfully treated with intravenous zanamivir: A case report

In patients with influenza-related myocarditis, prompt diagnosis and treatment are important. Intravenous zanamivir can be an alternative to oral oseltamivir, especially in severe cases and when drug intestinal malabsorption is suspected or proven.

Frequency of troponin elevations in patients with influenza infection during the 2017-2018 influenza season

Background

With the increased number of influenza cases observed during the 2017 – 2018 season, patients may be at a greater risk of cardiac related complications as a sequela of viral illness. We described the frequency of troponin elevations in patients with influenza infection during the 2017 – 2018 influenza season.

Methods

This was a retrospective, single-center observational study. All patients aged 18 years or older and had laboratory confirmed influenza viral infection were included in the study. Troponins were considered elevated if greater than 0.3 ng/mL. Electronic health records were reviewed for demographics, laboratory values, coronary artery disease history, electrocardiography, echocardiography results, and incidence of inpatient mortality.

Results

A total of 1,131 patients had lab confirmed influenza infection. Majority of the influenza strains were influenza A, 76.2% (n = 863), and the rest of the influenza strains comprised of influenza B, 23.8% (n = 270). Thirty three (2.9%) patients had elevation of troponin levels greater than 0.3 ng/mL. Most of the patients with elevated troponin levels had influenza A infection (90.9%, n = 30), of which H3 subtype was the most common (48.5%, n = 16). Fifteen patients (45.5%) had a myocardial infarction, 20 (60.6%) had left ventricular abnormalities visualized on echocardiogram, and four (12.1%) died while inpatient.

Conclusions

Our results describe the frequency of troponin elevations in patients with influenza infection at our institution during the 2017 – 2018 influenza season.

Influenza

Influenza A and B viruses are orthomyxoviruses with three important envelope glycoproteins: hemagglutinin (HA), neuraminidase (NA), and matrix proteins. Influenza viruses have developed ways to evade the body's immune response using an antigenic variation known as antigenic shift (replacement of HA and NA antigens with novel subtypes from noninfluenza viruses) and drift (mutations within antibody-binding sites in HA and or NA). Because of new influenza viruses constantly emerging from antigenic shift and drift, new influenza vaccines are required each year. Human-to-human transmission of influenza occurs each winter and early spring through small-particle aerosols or droplets. The influenza virus attacks epithelial cells of the upper and lower respiratory tract, with the potential for secondary bacterial infection and acute respiratory distress syndrome (ARDS). The symptoms of influenza infection include fever, headache, cough, sore throat, myalgia, and nasal congestion. Lower respiratory tract manifestations such as pneumonia and bronchiolitis are virtually indistinguishable from other viral infections. Children with certain comorbidities, such as chronic lung disease and severe neurologic impairment, are at higher risk of influenza-related complications. The most reliable test for influenza is reverse transcription polymerase chain reaction (RT-PCR). Rapid antigen tests have lower sensitivity and specificity and are not reliable during periods of low influenza activity. Antiviral treatment with NA inhibitors can shorten the duration of fever, symptoms, and hospitalization, especially when started within 48 hours of influenza illness onset. Prevention of influenza through annual influenza vaccination is recommended for all children 6 months of age and older. The vaccines contain three or four influenza subtypes, chosen depending on the circulating strains. The two formulations approved for children are the inactivated influenza vaccine (IIV) and live-attenuated influenza vaccine (LAIV).

A Fatal Case of Influenza B Myocarditis with Cardiac Tamponade

Background

Influenza B is generally regarded as a less severe counterpart to influenza A, typically causing mild upper respiratory symptoms. Myocardial involvement with influenza B is a rare complication, better described in children than adults. However, when it occurs, it can lead to profound myocarditis with progression to shock requiring aggressive supportive care.

Case Presentation

We present a case of cardiac tamponade in the setting of influenza B infection in a previously healthy 57-year-old woman, with progression to refractory shock and death. Autopsy revealed myocardial necrosis with infiltration of CD3+ lymphocytes, and little evidence of viral pneumonia.

Conclusions

Myocarditis is a rare complication of influenza B in adults, and subsequent pericardial effusion with tamponade physiology is a previously unreported event in an otherwise healthy adult without other medical comorbidities. While rare, this is a serious and potentially fatal complication that clinicians should be aware of when evaluating a patient with suspected viral illness who is exhibiting shock physiology.

Severe epidemic myalgia with an elevated level of serum interleukin-6 caused by human parechovirus type 3: a case report and brief review of the literature

BACKGROUND

Human parechovirus type 3 (HPeV-3) is known to cause cold-like symptoms, diarrhea, or severe infections such as sepsis in infants and children. In adults, HPeV-3 infection is rarely diagnosed because the symptoms are generally mild and self-limiting; however, this infection has been linked to epidemic myalgia, regardless of the presence of underlying diseases, immunosuppression, or sex.

CASE PRESENTATION

We describe an adult case of severe systemic myalgia and orchiodynia after infection with HPeV-3, which was transmitted from the child of the patient. Interleukin-6 (IL-6) level was found to be elevated in the patient's serum.

CONCLUSION

Severe myalgia associated with HPeV-3 infection is potentially caused by an elevated serum level of IL-6.

The Prevalence and Findings of Subclinical Influenza-associated Cardiac Abnormalities among Japanese Patients

Objective Although life-threatening cardiac complications in influenza infection are rare, subclinical influenza-associated cardiac abnormalities may occur more frequently. We investigated the prevalence of subclinical cardiac findings. Methods After obtaining their written informed consent, 102 subjects were enrolled in the present study. The study subjects underwent a first set of examinations, which included electrocardiography (ECG), echocardiography, and the measurement of their cardiac enzyme levels. Those with one or more abnormal findings among these examinations were encouraged to undergo a repeat examination 2 weeks later. Results Among the 102 subjects enrolled, 22 (21.6%) were judged to have cardiac findings, including ST-T abnormalities, pericardial effusion, diastolic dysfunction, and cardiac enzyme elevation. Eighteen of these 20 subjects underwent a second screening at a median of 14 days later, and it was found that 11 of the 18 subjects were free from cardiac findings on this second examination. This suggested that the abnormalities were only transient and they therefore might have been associated with influenza. Approximately 20% of the influenza patients enrolled had cardiac findings, including ST-T segment abnormalities, pericardial effusion, and cardiac enzyme elevation. Conclusion Among the 102 patients who were studied, the cardiac findings were only mild and transient; however, physicians should be aware of influenza infection-associated cardiac abnormalities because such abnormalities may not be rare.

The hidden burden of influenza: A review of the extra-pulmonary complications of influenza infection

Severe influenza infection represents a leading cause of global morbidity and mortality. Although influenza is primarily considered a viral infection that results in pathology limited to the respiratory system, clinical reports suggest that influenza infection is frequently associated with a number of clinical syndromes that involve organ systems outside the respiratory tract. A comprehensive MEDLINE literature review of articles pertaining to extra‐pulmonary complications of influenza infection, using organ‐specific search terms, yielded 218 articles including case reports, epidemiologic investigations, and autopsy studies that were reviewed to determine the clinical involvement of other organs. The most frequently described clinical entities were viral myocarditis and viral encephalitis. Recognition of these extra‐pulmonary complications is critical to determining the true burden of influenza infection and initiating organ‐specific supportive care.

Impact of A/H1N1 influenza in children at a Brazilian University Hospital

BACKGROUND

A/H1N1 influenza is a viral disease that affects a significant part of the population mainly in winter, leading to increased number of medical consultations, hospitalizations and consequently care spending in emergency.

METHODS

This is a case-series retrospective study, involving patients admitted to a tertiary hospital in southern Brazil in 2016 with a clinical diagnosis of acute respiratory infection of the influenza type and laboratory confirmation of influenza A/H1N1.

RESULTS

64 patients were included, mostly male, median age of 48.3 months. Chronic underlying diseases were found in 73% of the patients, and these patients evolved to the most unfavorable outcome. About vaccination, of the 57 patients with an age range for vaccination, only 28% had complete vaccination coverage. The main clinical manifestations found in the included patients were fever, cough, intercostal indrawing, wheezing, tachypnea and pulmonary crackles. These patients were mainly followed-up with laboratory tests and chest X-ray. Consolidation was evident in 43% of patients followed by interstitial infiltrate in 33%. A five-day course of neuraminidase inhibitor was prescribed for all patients, as recommended by the WHO, but due to the complications, 73% of the patients required antibiotic therapy, and 61% oxygen therapy. The majority of patients had a favorable outcome, but 11 required intensive care and one died.

CONCLUSIONS

A/H1N1 influenza persists as an important public health problem, mainly due to high morbidity and hospitalization rates. It is important to identify patients with A/H1N1 influenza and clinical situations with higher risk of complications. Through this study, it is possible to analyze the characteristics of pediatric patients with A/H1N1 influenza and mainly to emphasize assistance of populations with comorbidities, since they present higher rates of complications and death.

Non-invasive differentiation of idiopathic inflammatory myopathy with cardiac involvement from acute viral myocarditis using cardiovascular magnetic resonance imaging T1 and T2 mapping

BACKGROUND

Idiopathic inflammatory myopathy (IIM) is a group of autoimmune diseases with systemic myositis which may involve the myocardium. Cardiac involvement in IIM, although often subclinical, may mimic clinical manifestations of acute viral myocarditis (AVM). Our aim was to investigate the usefulness of the combined analysis of cardiovascular magnetic resonance (CMR) T1 and T2 mapping parameters measured both in the myocardium and in the thoracic skeletal muscles to differentiate AVM from IIM cardiac involvement.

METHODS

Sixty subjects were included in this retrospective study (36 male, age 45 ± 16 years): twenty patients with AVM, twenty patients with IIM and cardiac involvement and twenty healthy controls. Study participants underwent CMR imaging with modified Look-Locker inversion-recovery (MOLLI) T1 mapping and 3-point balanced steady-state-free precession T2 mapping. Relaxation times were quantified after endocardial and epicardial delineation on basal and medial short-axis slices, as well as in different thoracic skeletal muscle groups present in the CMR field-of-view. ROC-Analysis was performed to assess the ability of mapping indices to discriminate the study groups.

RESULTS

Mapping parameters in the thoracic skeletal muscles were able to discriminate between AVM and IIM patients. Best skeletal muscle parameters to identify IIM from AVM patients were reduced post-contrast T1 and increased extracellular volume (ECV), resulting in an area under the ROC curve (AUC) of 0.95 for post-contrast T1 and 0.96 for ECV. Conversely, myocardial mapping parameters did not discriminate IIM from AVM patients but increased native T1 (AUC 0.89 for AVM; 0.84 for IIM) and increased T2 (AUC 0.82 for AVM; 0.88 for IIM) could differentiate both patient groups from healthy controls.

CONCLUSION

CMR myocardial mapping detects cardiac inflammation in AVM and IIM compared to normal myocardium in healthy controls but does not differentiate IIM from AVM. However, thoracic skeletal muscle mapping was able to accurately discern IIM from AVM.

Pharmacokinetics of Oral and Intravenous Oseltamivir Treatment of Severe Influenza B Virus Infection Requiring Organ Replacement Therapy

BACKGROUND AND OBJECTIVES

Patients with severe influenza virus infection, multi-organ failure and organ replacement therapy may absorb and metabolize neuraminidase inhibitors differently. Systematic pharmacokinetic/pharmacodynamic clinical trials are currently lacking in this high-risk group. Inadequate dosing increases the risk of treatment failure and drug resistance, especially in severely ill patients with elevated virus loads. This study aims to explore the impact of organ replacement therapy on oseltamivir drug concentrations.

METHODS

Serial pharmacokinetic/pharmacodynamic measurements and Sieving coefficients were assessed in two patients with severe influenza B infection requiring organ replacement therapy.

RESULTS

Patient #1, a 9-year-old female with severe influenza B virus infection, biventricular assist device, and continuous veno-venous hemodiafiltration, received 75 mg oral oseltamivir twice-daily for 2 days, then intravenous oseltamivir with one-time renoprotective dosing (40 mg), followed by regular intravenous administration of 100 mg twice-daily. Plasma oseltamivir carboxylate concentrations were stable initially, but only regular administration of 100 mg resulted in virus load decline and clinical improvement. Patient #2, a 28-year-old female with influenza B virus infection requiring extracorporeal membrane oxygenation, received 75 mg oral oseltamivir twice-daily, resulting in erratic oseltamivir blood concentrations. In both patients, drug concentrations remained well within safety margins.

CONCLUSIONS

In severe cases with multi-organ failure, administration of 100 mg intravenous oseltamivir twice-daily provided reliable drug concentrations, as opposed to renoprotective and oral dosing, thereby minimizing the risk of treatment failure and drug resistance. Evidence-based pediatric dosing recommendations and effective intravenous antiviral treatment modalities are needed for intensive care patients with life-threatening influenza disease.

A case of influenza type a myocarditis that presents with ST elevation MI, cardiogenic shock, acute renal failure, and rhabdomyolysis and with rapid recovery after treatment with oseltamivir and intra-aortic balloon pump support

We present a 59-year-old black male with history of type-1 diabetes and alcohol abuse. Patient became critically ill after a 5-day period of burning throat discomfort. On arrival patient was lethargic, in cardiogenic shock with a blood pressure of 81/47mmHg. Immediate diagnoses included diabetic ketoacidosis, acute renal failure, and possible septic shock. He was intubated, resuscitated with intravenous fluids, maintained on three inotropic agents, and given empiric wide spectrum antibiotics. An ECG showed a new ST elevation MI and an echocardiogram showed severe LV dysfunction. Cardiac catheterization showed clean coronaries. With appropriate treatment patient recovered 10days later.

Fulminant lymphocytic myocarditis associated with orbital myositis and diaphragmatic paralysis

Although the clinical presentation of myocarditis is very diverse, ranging from mild dyspnea to hemodynamic collapse, myocarditis accompanied with extracardiac myositis is extremely rare. We report a single case of fulminant myocarditis associated with orbital myositis and diaphragmatic paralysis in a 40-year-old man, which was successfully managed by immunosuppressive therapy with steroid.

Discordant Electrocardiogram Left Ventricular Wall Thickness and Strain Findings in Influenza Myocarditis

A 42-year-old man presented with a viral prodrome and tested positive for influenza A. He rapidly deteriorated developing cardiogenic shock, rhabdomyolysis, and acute kidney injury. Patient improved 1 week later with supportive measures including vasopressors, inotropes, and an intraaortic balloon pump. We report this case as it highlights the discordance between echocardiographic ventricular wall thickening as a result of myocardial edema, and electrocardiographic findings at presentation, with a reversal in findings at time of resolution. Additionally, there was some suggestion of a regional pattern to the reduced longitudinal strain.

Transient cardiac injury during H7N9 infection

BACKGROUND

Recent reports have characterized virological and clinical features of the novel reassortant avian-origin influenza A (H7N9) virus. However, cardiovascular involvement during H7N9 infection is still unclear. In this study, we evaluate cardiac injury among H7N9-infected patients.

MATERIALS AND METHODS

A total of 40 patients who were laboratory-confirmed with H7N9 infection were retrospectively included and grouped by Acute Physiology and Chronic Health Evaluation II (APACHE II) score into four subgroups I(0-10), II(11-20), III(21-30) and IV(31-71). Cardiovascular complications and markers of cardiac injury including creatinine kinase (CK), CK iso-enzyme (CK-MB), cardiac troponin I (cTNI) and brain natriuretic peptide (BNP) were assessed. Electrocardiogram (ECG) and echocardiography (ECHO) were also performed.

RESULTS

Half of patients manifested with cardiovascular complications, with hypotension (47.5%) and heart failure (40.0%) the most prevalent. CK, CK-MB and cTNI showed marked increase with H7N9 virus infection but significantly decreased after H7N9 viral tests turned negative. More than half of patients presented with an abnormal ECG, but most of them are benign changes. ECHO examination showed different degree of impairment of cardiac function. Pulmonary artery systolic pressure was increased in all groups. Cardiac damage was more evident in patients with higher APACHE II score.

CONCLUSIONS

H7N9 virus exerts a transient impairment on the cardiovascular system. Patients with a higher APACHE II score are more susceptible to cardiac damage.

Management of fulminant myocarditis: a diagnosis in search of its etiology but with therapeutic options

Fulminant myocarditis is a clinical syndrome with signs of acute heart failure, cardiogenic shock, or life-threating rhythm disturbances in the context of suspected myocarditis. It is not an etiological diagnosis, but may have different underlying causes and pathogenetic processes - viral, bacterial, toxic, and autoreactive. Clinical management of the disease entity at the acute stage involves hemodynamic monitoring in an intensive care unit or similar setting. Rapid routine work-up is mandatory with serial EKGs, echocardiography, cardiac MRI, heart catheterization with endomyocardial biopsy for histology, immunohistology, and molecular analysis for the underlying infection and pathogenesis. Heart failure therapy is warranted in all cases according to current guidelines. For fulminant autoreactive myocarditis, immunosuppressive treatment is beneficial; for viral myocarditis, IVIg can resolve the inflammation, reduce the viral load, and even eradicate the microbial agent. ECMO, IABP, ventricular assist devices, LifeVest, or ICD implantation can bridge to recovery or to heart transplantation.

Atypical clinic presentation of pandemic influenza A successfully rescued by extracorporeal membrane oxygenation - Our experience and review of the literature

The novel pandemic influenza A (H1N1) caused an epidemic of critical illness, and some patients developed severe acute respiratory distress syndrome (ARDS) or severe cardiopulmonary failure despite the use of conventional management. Extracorporeal membrane oxygenation (ECMO) support may successfully rescue these severely ill patients. We demonstrate the causative role of H1N1 in refractory ARDS of a previously healthy 15-year-old man who presented to the intensive care unit with a hypoxic and persistent cardiogenic shock refractory to conventional management as the leading symptom of influenza A. Because of compromised cardiopulmonary function, venovenous ECMO was applied 24 h after admission. Despite that the patient was manifesting heart failure, we decided the placement of venovenous ECMO because we believed that the real problem was the uncontrollable hypoxia and hypercapnia. A normal left ventricular ejection fraction was documented on a 2D echocardiography on day 2. The patient, after 6 days of ECMO, recovered completely and was successfully weaned from the mechanical ventilator on the 9th day after admission. The patient was discharged from the hospital on the 15th day. This experience showed that ECMO can be lifesaving for severe H1N1 infection also in patients with atypical clinical presentation of influenza.

Productive infection of human skeletal muscle cells by pandemic and seasonal influenza A(H1N1) viruses

Besides the classical respiratory and systemic symptoms, unusual complications of influenza A infection in humans involve the skeletal muscles. Numerous cases of acute myopathy and/or rhabdomyolysis have been reported, particularly following the outbreak of pandemic influenza A(H1N1) in 2009. The pathogenesis of these influenza-associated myopathies (IAM) remains unkown, although the direct infection of muscle cells is suspected. Here, we studied the susceptibility of cultured human primary muscle cells to a 2009 pandemic and a 2008 seasonal influenza A(H1N1) isolate. Using cells from different donors, we found that differentiated muscle cells (i. e. myotubes) were highly susceptible to infection by both influenza A(H1N1) isolates, whereas undifferentiated cells (i. e. myoblasts) were partially resistant. The receptors for influenza viruses, α2-6 and α2-3 linked sialic acids, were detected on the surface of myotubes and myoblasts. Time line of viral nucleoprotein (NP) expression and nuclear export showed that the first steps of the viral replication cycle could take place in muscle cells. Infected myotubes and myoblasts exhibited budding virions and nuclear inclusions as observed by transmission electron microscopy and correlative light and electron microscopy. Myotubes, but not myoblasts, yielded infectious virus progeny that could further infect naive muscle cells after proteolytic treatment. Infection led to a cytopathic effect with the lysis of muscle cells, as characterized by the release of lactate dehydrogenase. The secretion of proinflammatory cytokines by muscle cells was not affected following infection. Our results are compatible with the hypothesis of a direct muscle infection causing rhabdomyolysis in IAM patients.

Influenza B-induced refractory cardiogenic shock: a case report

Background

An association between influenza A viruses and myocarditis was noted during the 1918 influenza pandemic. Since then, the link between the influenza B virus and fulminant myocarditis or cardiogenic shock has been rarely reported.

Case presentation

In February 2013, a 50 year-old-woman without known heart disease presented in profound cardiogenic shock with a left ventricular ejection fraction of 10%. Her presentation was preceded by six days of fever, chills, myalgia and fatigue. She had a junctional tachycardia, a troponin I of 12.6 ng/ml and her coronary angiography demonstrated normal coronary arteries. Percutaneous extracorporeal membrane oxygenation was required. An endotracheal aspirate at admission was positive for influenza B. All other respiratory, blood and urine cultures were negative. On day 7, a repeat echocardiography demonstrated significant recovery of left ventricular function with an ejection fraction of 50%. She was later discharged home in good condition.

Conclusions

Influenza B infection can be complicated by fulminant cardiomyopathy leading to cardiogenic shock in adults without preexisting cardiac disease.

Myocardial dysfunction during H1N1 influenza infection

PURPOSE

The purpose of the study is to evaluate the incidence and hemodynamic consequences of right ventricular (RV) and left ventricular (LV) dysfunction in critically ill patients with H1N1 infection.

PATIENTS AND METHODS

This is a retrospective analysis of all patients admitted to the intensive care unit of an academic hospital between October 2009 and March 2011 with severe H1N1 infection. Hemodynamic measurements and respiratory conditions were noted daily during the intensive care unit stay.

RESULTS

Forty-six patients were admitted with severe H1N1 infection. Echocardiography was obtained in 39 patients on admission: 28 (72%) had abnormal ventricular function, of whom 13 (46%) had isolated LV abnormalities, 11 (39%) had isolated RV dysfunction, and 4 (14%) had biventricular dysfunction. Echocardiography was repeated in 19 of the 39 patients during their hospitalization: RV function tended to worsen with time, but LV function tended to normalize. The ventricular abnormalities were not associated with history, severity of the respiratory failure, or hemodynamic status. However, patients with ventricular dysfunction needed more aggressive therapy, including more frequent use of vasopressor and inotropic agents and of rescue ventilatory strategies, such as inhaled nitric oxide, prone positioning, and extracorporeal membrane oxygenation.

CONCLUSIONS

These observations emphasize the high incidence of cardiac dysfunction in patients with H1N1 influenza infections.

Myocarditis Associated with Influenza A H1N1pdm2009

Acute myocarditis is a well-known complication of influenza infection. The frequency of myocardial involvement in influenza infection varies widely, with the clinical severity ranging from asymptomatic to fulminant varieties. The worst cases can result in death due to impaired cardiac function, although such fulminant myocarditis associated with influenza infection is rare, as shown by previous papers. Following the 2009 influenza pandemic, we reported on the clinical features of a cohort of 15 patients in Japan with H1N1pdm2009 myocarditis. In our subsequent survey of the literature for case reports or series of patients with myocarditis associated with H1N1pdm2009, we identified 58 detailed cases. We discuss here the high prevalence of fulminant myocarditis (36/58, 62%) among patients reported to have myocarditis associated with H1N1pdm2009. Mechanical circulatory support was required in 17 of the patients with fulminant myocarditis, 13 of whom recovered. We stress the need for increased awareness of influenza-associated myocarditis; such knowledge will facilitate earlier diagnosis and treatment of this fatal complication during future influenza pandemics.

Leptin, insulin and thyroid hormones in a cohort of Egyptian obese Down syndrome children: a comparative study

BACKGROUND

Obesity is a major worldwide health problem. It is commonly observed in Down syndrome individuals than in the general population. The reason for increased risk of obesity in DS is unclear.The current study was designed to clarify differences in some obesity- related hormones in a group of prepubertal Down syndrome children.

METHODS

Thirty six Egyptian children with Down syndrome were enrolled in this study, divided according to their body mass index (BMI) into 23 obese and13 non obese. Another group of 43 non Down children were recruited, they were divided according to their BMI into 20 patients having simple obesity and 23 non obese, as control groups. Fasting blood samples were collected for estimation of fasting blood glucose (FBG), insulin, leptin, free thyroxin (FT4), thyroid stimulating hormones (TSH) and creatine kinase (CK). Insulin resistance was assessed by Homeostasis Model Assessment method (HOMA-IR). The ratio of leptin to BMI (LEP/BMI) was used as an index of leptin resistance.

RESULTS

Median values of FBG, insulin, and HOMA-IR were significantly higher in Down versus non Down groups, while median values of leptin and leptin resistance were non-significantly different among Down versus non Down groups. Median TSH values were non- significantly different between obese Down and obese non Down. Although the median values of TSH and FT4 were within normal range in Down groups, four cases of subclinical hypothyroidism were encountered. Leptin levels were correlated with insulin and IR but not with TSH in Down groups.

CONCLUSION

Increased circulating leptin, a marker of leptin resistance in obese children with Down syndrome seems to be similar to that in children with simple obesity. Elevated FBG and insulin in obese Down children highlights the presence of early IR. Associated myopathy evidenced by mildly elevated CK levels could be an added factor for obesity in such group of patients.

New treatments for influenza

Influenza has a long history of causing morbidity and mortality in the human population through routine seasonal spread and global pandemics. The high mutation rate of the RNA genome of the influenza virus, combined with assortment of its multiple genomic segments, promote antigenic diversity and new subtypes, allowing the virus to evade vaccines and become resistant to antiviral drugs. There is thus a continuing need for new anti-influenza therapy using novel targets and creative strategies. In this review, we summarize prospective future therapeutic regimens based on recent molecular and genomic discoveries.