Influenza-associated myositis: a single-centre, 5-year retrospective study

Cellular mechanisms of acute rhabdomyolysis in inherited metabolic diseases

Acute rhabdomyolysis (RM) constitutes a life-threatening emergency resulting from the (acute) breakdown of skeletal myofibers, characterized by a plasma creatine kinase (CK) level exceeding 1000 IU/L in response to a precipitating factor. Genetic predisposition, particularly inherited metabolic diseases, often underlie RM, contributing to recurrent episodes. Both sporadic and congenital forms of RM share common triggers. Considering the skeletal muscle's urgent need to rapidly adjust to environmental cues, sustaining sufficient energy levels and functional autophagy and mitophagy processes are vital for its preservation and response to stressors. Crucially, the composition of membrane lipids, along with lipid and calcium transport, and the availability of adenosine triphosphate (ATP), influence membrane biophysical properties, membrane curvature in skeletal muscle, calcium channel signaling regulation, and determine the characteristics of autophagic organelles. Consequently, a genetic defect involving ATP depletion, aberrant calcium release, abnormal lipid metabolism and/or lipid or calcium transport, and/or impaired anterograde trafficking may disrupt autophagy resulting in RM. The complex composition of lipid membranes also alters Toll-like receptor signaling and viral replication. In response, infections, recognized triggers of RM, stimulate increased levels of inflammatory cytokines, affecting skeletal muscle integrity, energy metabolism, and cellular trafficking, while elevated temperatures can reduce the activity of thermolabile enzymes. Overall, several mechanisms can account for RMs and may be associated in the same disease-causing RM.

Influenza and Aging: Clinical Manifestations, Complications, and Treatment Approaches in Older Adults

Influenza, a highly contagious respiratory viral illness, poses significant global health risks, particularly affecting older and those with chronic health conditions. Influenza viruses, primarily types A and B, are responsible for seasonal human infections and exhibit a propensity for antigenic drift and shift, contributing to seasonal epidemics and pandemics. The severity of influenza varies, but severe cases often lead to pneumonia, acute respiratory distress syndrome, and multiorgan failure. Older adults, especially those over 65 years of age, face increased risks of immune senescence, chronic comorbidities, and decreased vaccine efficacy. Globally, influenza affects millions of people annually, with significant morbidity and mortality among older. Epidemiological patterns vary with climate, and risk factors include age, immunocompromised status, and preexisting chronic conditions. In older adults, influenza frequently results in hospitalization and death, which is exacerbated by immunosenescence and biological organ changes associated with aging. Clinical manifestations range from mild symptoms to severe complications such as viral pneumonia and multiorgan failure. Diagnosis often relies on antigen or molecular tests, with radiological examination aiding in severe cases. Treatment primarily involves antiviral agents, such as oseltamivir and peramivir, with the greatest benefit observed when initiated early. Management of severe cases may require hospitalization and supportive care, including addressing complications, such as secondary bacterial infections and cardiovascular events. This article highlights the need for improved vaccination strategies and novel treatments, including monoclonal antibodies and adoptive T cell therapies, to better manage severe influenza infections in vulnerable populations such as older.

Benign Acute Myositis in Children: A Case Series

Benign acute myositis is a rare and transient condition that usually occurs after a viral upper respiratory infection. Several viruses have been associated with this process particularly influenza B. Viral myositis frequently occurs in school-age children with a male predominance. Patients complain about symmetrical calf muscle pain and uncoordinated gait and functional impairment. The presentation is associated with increased creatine phosphokinase. Benign acute myositis is a self-limiting condition with an excellent prognosis. Myoglobinuria is uncommon but severe. We report a case series of three patients presented with viral myositis. Pediatricians must be aware of this pathology to reach an early diagnosis and avoid unnecessary diagnosis investigations. It is also important to reach out to myoglobinuria, which can lead to renal impairment.

Benign acute childhood myositis: a scoping review of clinical presentation and viral etiology

Benign acute childhood myositis is a benign phenomenon often associated with influenza in children. The aim of this scoping review was to analyze the typical clinical picture and characteristics of benign acute childhood myositis patients. Furthermore, we aimed to analyze the epidemiology and viral findings. We performed a systematic scoping review. We searched PubMed, Scopus, Web of Science, and CINAHL databases in August 2023. We included observational studies that focused on children and reported at least 10 children. Our main outcome was to describe the typical clinical picture of benign acute childhood myositis patients. Furthermore, we aimed to report the typical laboratory findings and virus findings. A total of 211 studies were screened, and 22 studies were included in this review. The included studies were mainly from Europe (13 studies) and Asia (5 studies). Two studies were prospective, and the rest were retrospective. The mean age of the patients was 6.8 (CI 5.8-7.8) years. Benign acute childhood myositis appeared to be more prevalent among boys in all studies. The most prevalent symptoms were bilateral leg pain (pooled prevalence 92%), followed by fever (80%) and inability to walk (56%). Hospitalization rates varied between 4 and 100%, and the mean hospital stay was 3.6 (CI 3.3-3.9) days. Influenza B was the most common virus detected, followed by influenza A. Other reported viruses included herpes simplex, coxsackie-, enteroviruses, adeno-, respiratory syncytial, and parainfluenza viruses. All studies reported creatinine kinase levels, and the reported mean values varied between 100 and 4000 U/L, whereas only five studies reported C-reactive protein which was only slightly elevated.

CONCLUSION

According to a systematic assessment of published literature, benign acute childhood myositis patients were typically school-aged children, presenting with bilateral leg pain, fever, and inability to walk. Influenza A and B were the most reported viruses, but multiple other viruses have been associated with benign acute childhood myositis. These patients have high creatinine kinase values, but their hospital stay was rather short. Overall, this review provides important information for clinicians on the characteristic presentation of benign acute childhood myositis, and these findings may help to better identify these patients and reduce unnecessary tests.

WHAT IS KNOWN

• Benign acute childhood myositis has been mainly associated with influenza viruses, especially B influenza. • Typical patients have been reported to be under school-aged children, and boys have been reported to have a higher incidence.

WHAT IS NEW

• Many non-influenza viruses were also associated with benign acute childhood myositis, such as herpes simplex, coxsackie-, entero-, adeno-, respiratory syncytial, and parainfluenza viruses. • Typical symptoms are bilateral calf pain, fever, and inability to walk and creatine kinase levels were reposted to be increased.

Viral Myositis in a Pediatric Patient Following Influenza Infection: A Case Report

Viral myositis is an uncommon sequela associated with influenza virus infection, more common in children. We report a case of a three-year-old girl who developed viral myositis after suffering from influenza A infection. The patient was found to have leg pain associated with difficulty in walking. The diagnosis was confirmed by physical examination and elevated creatine kinase (CK) level. Supportive measures, including rehydration and mitigation of fever, were sufficient. Antiviral therapy was not required. This case also underscores the importance of early diagnosis and supportive medical care in managing children with viral myositis. Persistently elevated levels of CK are also useful in diagnosis as they provide evidence of muscle damage sustained during virus infection. The immediate concern would be the reassurance of caregivers regarding cases that will almost always be resolved with supportive care instead of worsening progressively. Prevention of unnecessary courses of management will decrease the patient's anxiety and the parents' fears.

Neurological involvement related to the influenza virus in children: A 5-year single-centre retrospective study

INTRODUCTION

Inflammation related to influenza virus infection can lead to multiple neurological presentations. Encephalitis is one of them, mostly accompanied by seizures, with different profiles depending on the epidemics and previous medical conditions.

MATERIALS AND METHODS

All children presenting neurological symptoms and positive for influenza virus RNA detection in a respiratory sample between November 2018 and April 2023, hospitalized in the Department of Paediatric Neurology of Toulouse Children's Hospital, were retrospectively analysed.

RESULTS

Among the 1,277 children diagnosed with influenza in our centre, 131 (10.3 %) were hospitalized for neurological features. The year 2020-2021 was marked by zero incidence of positive influenza tests, associated with the COVID-19 pandemic. Among the 131 patients included, 71.6 % were under 5 years old. Most of them (80.9 %) were infected by influenza A virus. The first neurological symptoms were mainly seizures in 73.3 % of patients. Possible or confirmed encephalitis was observed in 29 % of cases, including one acute necrotizing encephalopathy. Few children (6.1 %) presented with acute myositis. Twenty-seven patients (20.6 %) had a personal history of significant previous neurological disorders. Most patients (88.5 %) displayed a rapid favourable outcome, marked by the disappearance of their neurological symptoms within the first 2 days. Anti-epileptic drugs were introduced in 1.5 % of cases, and adapted in 16.8 %, mainly in patients with febrile status epilepticus and an abnormal EEG.

CONCLUSION

Neurological features were frequently associated with influenza infection in children; most were transient. Effects on long-term neurodevelopmental outcomes need to be clarified as our follow-up was limited, especially in children with pre-existing neurological conditions.

Clinical Characteristics of 118 Pediatric Patients With Acute Benign Myositis Associated With Influenza A Virus Infection

OBJECTIVE

The objective of this study was to investigate the clinical and laboratory features of acute benign myositis associated with influenza A virus infection in children.

METHODS

A retrospective analysis was performed on the clinical data of 118 children with acute benign myositis associated with influenza A virus infection who were admitted to the Children's Hospital of Chongqing Medical University during the epidemic period of influenza A from February 2023 to May 2023.

RESULTS

(1) Most of the 118 children were preschool- or school-age. The most common symptom was sudden lower limb pain after fever, and bilateral calf myalgia was more common. The muscle enzyme spectrum ranged from 187.21 to 32191.00 μg/L (median: 3053 μg/L). Creatine kinase isoenzymes ranged from 5.15 to 749.7 μg/L (median 41.82 μg/L). Myoglobin ranged from 102.79 to 1200 μg/L (median 674.9 μg/L). (3) Examination: electromyography, muscle color Doppler ultrasound, radiograph and cardiac color Doppler ultrasound in Benign acute childhood myositis in children were rarely positive. (4) Treatment and prognosis: besides bed rest and a reduction of physical activity, oseltamivir treatment, drugs to improve energy metabolism, fluid replacement and alkalinization of symptomatic treatment. All children had a good prognosis without sequelae.

CONCLUSIONS

This study summarized and analyzed the clinical characteristics of acute benign myositis associated with influenza A infection in children with the aim of allowing rapid and early diagnosis of the disease and reducing unnecessary diagnostic tests and treatments. Closely monitoring myalgia and the muscle enzyme spectrum is recommended to exclude other neuromuscular and metabolic diseases.

Urea/Creatinine Ratio's Correlation with Creatine Kinase Normalization in Pediatric COVID-19 Patients with Myositis: Evaluating Prognostic and Predictive Value

Coronavirus disease 2019 (COVID-19) has been chiefly linked with substantial respiratory complications. However, emerging studies have brought attention to the occurrence of severe muscle inflammation (myositis) related to COVID-19, potentially leading to multi-organ failure and increased mortality. Myositis is generally characterized by heightened serum creatine kinase (CK) levels. Acute myositis is characterized by an infiltration of viruses into calf muscle fibers, which may cause a subsequent inflammatory response leading to calf muscle pain. Symptomatic and supportive management, along with explanation and reassurance, is all that is required in managing this condition. While the association between myositis and severe outcomes has been recognized in adults, it remains less understood in the pediatric population. The current retrospective study, conducted at Policlinico San Marco University Hospital in Catania, aimed to analyze clinical and laboratory factors associated with myositis in pediatric patients with SARS-CoV-2 infection. Between January 2022 and January 2023, ten pediatric patients diagnosed with myositis and SARS-CoV-2 infection were evaluated. The study highlighted clinical manifestations such as fever, calf muscle pain, and abnormal gait. Lab results showed elevated CK levels among other findings. All patients underwent treatment, with the majority recovering without complications. A notable correlation was observed between CK levels, blood urea nitrogen (BUN), and the urea/creatinine ratio (UCR). The study also discusses potential pathophysiological mechanisms behind SARS-CoV-2's impact on skeletal muscles, emphasizing an indirect inflammatory response. Our findings underscore that while myositis in children with SARS-CoV-2 infection appears to follow a benign and self-limiting trajectory, it is crucial to monitor specific markers for early intervention and management. Further research is warranted to elucidate the underlying mechanisms and improve clinical outcomes.

Rhabdomyolysis in Pediatric Patients with SARS-CoV-2 Infection

Background: Rhabdomyolysis is a rare but severe complication in adult patients with Coronavirus disease 2019 (COVID-19), which can result in acute kidney injury and death; however, it is rarely reported in pediatric patients. Methods: In this study, we retrospectively reviewed the clinical features and outcomes of rhabdomyolysis in pediatric patients aged 0–18 years with COVID-19 who were hospitalized at Taipei Tzu Chi Hospital, an epicenter of COVID-19 in northern Taiwan. Results: We treated eight patients with rhabdomyolysis during the omicron variant-Severe acute respiratory syndrome coronavirus 2 (omicron variant-SARS-CoV-2) community outbreak and none during the alpha variant endemic. These eight patients shared stereotypical presentations, including the presence of bilateral calf pain after defervescence. The creatinine kinase (CK) levels were between 1346 and 6937 U/L on admission, and clinical course was uneventful after aggressive saline hydration. Conclusion: Rhabdomyolysis is not a rare complication in pediatric patients with the omicron-SARS-CoV-2 infection, and reassurance of a good prognosis is important to alleviate family anxiety.

Patterns of Viral Arthropathy and Myalgia Following COVID-19: A Cross-Sectional National Survey

Introduction

Viral arthropathy is an increasingly recognized sequela of several viral pathogens including alphaviruses, hepatitis, and potentially coronaviruses. Case reports of viral arthropathy and myalgia associated with SARS-CoV-2 infection (COVID-19) both during active disease and following resolution of acute COVID-19 symptoms are becoming more prevalent. We sought to describe the prevalence of viral arthropathy and myalgia associated with COVID-19, as well as to identify factors that may predict these symptoms.

Methods

A national, cross-sectional survey was conducted using a questionnaire administered online. Subjects self-reporting previous confirmed COVID-19 were recruited using the Amazon Mechanical Turk crowdsourcing platform. Questionnaire items included demographics, frequency and severity of common COVID-19 symptoms, requirement for hospitalization or mechanical ventilation, subject recall of arthropathy or myalgia onset, duration, and severity, as well as WOMAC score. Binary logistic regression was used to identify potential predictive co-variates for the development of either arthropathy or myalgia.

Results

A total of 3222 participants completed the arthropathy/myalgia questionnaire with 1065 responses remaining for analysis following application of exclusion criteria, data integrity review, and omission of respondents with confounding conditions. Of the 1065 cases, 282 (26.5%) reported arthralgia and 566 (53.2%) reported myalgia at some point during or after COVID-19 with 9.9% and 6.0% reporting onset of arthralgia or myalgia, respectively, after resolution of acute COVID-19 symptoms. The presence of several commonly reported COVID symptoms or indicators of disease severity was predictive of arthralgia including hospitalization (OR 3.7; 95% CI 2.4 to 5.8), sore throat (OR 2.3; 95% CI 1.5 to 3.5), fatigue (OR 2.9; 95% CI 1.7 to 4.9), and ageusia/anosmia (OR 1.7; 95% CI 1.1 to 2.7).

Discussion

Based on these results, new-onset arthropathy and myalgia following COVID-19 resolution may be an increasingly encountered etiology for pain.

Duvira Antarctic polysaccharide inhibited H1N1 influenza virus-induced apoptosis through ROS mediated ERK and STAT-3 signaling pathway

BACKGROUND

The H1N1 influenza virus causes acute respiratory tract infection, and its clinical symptoms are very similar to those of ordinary influenza. The disease develops rapidly. If the flu is not treated, complications such as pneumonia, respiratory failure, and multiple organ damage can occur, resulting in a high fatality rate. Influenza virus mutates rapidly. At present, there is no specific drug for H1N1, so it is an urgent need for clinical care to find new drugs to treat H1N1.

MATERIALS AND METHODS

The polysaccharide derived from Durvillaea Antarctica green algae has a certain antiviral effect. In this study, the results of CCK-8, apoptosis cycle detection, JC-1 and Western blotting proved that Duvira Antarctic polysaccharide (DAPP) has the ability to inhibit H1N1 infection.

RESULTS

CCK-8 test showed that the DAPP with concentration at 32 μg/mL had no toxicity to MDCK cells. In addition, DAPP reduced cell apoptosis by inhibiting the ERK signaling pathway. Meanwhile, DAPP could increase the expression of STAT3 and significantly inhibited proinflammatory cytokines.

CONCLUSIONS

In summary, these results suggested that DAPP may be potential with the ability to resist the H1N1 influenza virus.

Neuromuscular Complications of SARS-CoV-2 and Other Viral Infections

In this article we review complications to the peripheral nervous system that occur as a consequence of viral infections, with a special focus on complications of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). We discuss neuromuscular complications in three broad categories; the direct consequences of viral infection, autoimmune neuromuscular disorders provoked by viral infections, and chronic neurodegenerative conditions which have been associated with viral infections. We also include discussion of neuromuscular disorders that are treated by immunomodulatory therapies, and how this affects patient susceptibility in the current context of the coronavirus disease 2019 (COVID-19) pandemic. COVID-19 is associated with direct consequences to the peripheral nervous system via presumed direct viral injury (dysgeusia/anosmia, myalgias/rhabdomyolysis, and potentially mononeuritis multiplex) and autoimmunity (Guillain Barré syndrome and variants). It has important implications for people receiving immunomodulatory therapies who may be at greater risk of severe outcomes from COVID-19. Thus far, chronic post-COVID syndromes (a.k.a: long COVID) also include possible involvement of the neuromuscular system. Whether we may observe neuromuscular degenerative conditions in the longer term will be an important question to monitor in future studies.

Evaluation of Influenza Patients Admitted in 2019–2020 Flu Season

Objective Influenza viruses are among the most common respiratory pathogens for all age groups, and may cause seasonal outbreaks. The aim of our study was to describe the clinical characteristics of influenza cases in the 2019–2020 flu season and to study the risk factors for hospital admission and complications.

Methods This was a retrospective study in 251 children (group 1: nonhospitalized; group 2: hospitalized) with influenza in the 2019–2020 flu season. Data on demographic features, influenza type, complaints, complications, and hospitalization length were collected and recorded.

Results Influenza A was detected in 199 (79.3%) patients, and influenza B was detected in 52 (20.7%); 43.4% of patients were girls and 56.6% were boys. The mean age of the patients was 3.91 ± 3.3 years (16 days to 18 years). A total of 52 (20.7%) patients were hospitalized. The age of the patients in group 2 was lower than that in group 1 (3.1 vs. 4.2 years, p = 0.03). Group 2 patients were more likely to have creatine kinase (CK) elevation, febrile seizures, and physical examination abnormalities. Group 2 patients were also more likely to have influenza A. Patients with febrile seizures, chronic diseases, abnormal physical examination findings, developed complications, and additional drug use apart from oseltamivir in the treatment were also more likely to require hospitalization.

Conclusion Infants and children with chronic diseases, history of febrile seizures, complications, and the use of drugs other than antiviral drugs should be carefully evaluated in case they need hospitalization. Increasing vaccination rates, initiation of antiviral treatment for selected patients, and close monitoring of patients in risk groups can decrease morbidity and mortality. Myalgias are a common complaint in patients with acute influenza infection. Previous studies suggest CK measurement be part of the work-up for the hospitalized patient with acute influenza infection.