Benign Acute Childhood Myositis During Influenza B Outbreak

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.

Benign acute childhood myositis: A 5-year retrospective study

BACKGROUND

Benign acute childhood myositis (BACM) is a rare, transient, and self-limited inflammatory condition of the skeletal muscle that usually occurs after a viral infection. It affects pre-school and school-aged children at a median age of 6-9 years, with a male predominance. Patients can be managed with analgesia, rest, and adequate hydration at home.

METHODS

A retrospective review was carried out of patients' clinical records with an elevated level of creatine phosphokinase (CPK) who presented to the pediatric emergency department between January 1, 2015 and December 31, 2019.

RESULTS

Out of 174 cases of elevated CPK values, 100 corresponded to BACM-compatible clinical presentations (n = 96). There was a male predominance (77%) with a median age of 6 years. There were more cases registered in 2019 compared with the previous years. The most frequently reported prodromal symptoms were fever, cough, and rhinorrhea. Bilateral calf pain was the most frequently reported BACM symptom, followed by gait complaints and refusal to walk. Hospitalization was an independent predictor of CPK levels. In two cases there was myoglobinuria. The most common hematological findings were leukopenia and thrombocytopenia.

CONCLUSION

Our results regarding male predominance, median age, and hematological findings are similar to the published reports. The outbreak during 2019 coincided with the 2019/2020 flu season. During this period, influenza B was the most prevalent virus and it is known to be the most myotrophic one. Physicians often take into consideration CPK levels during inpatient admission. All patients recovered fully, emphasizing the fact that BACM is benign, self-limited, and with an excellent prognosis.

Benign acute childhood myositis associated with influenza A/B in the paediatric emergency department and the efficacy of early-onset oseltamivir

AIM

To investigate the association of benign acute childhood myositis (BACM) with respiratory viruses. Also, we aimed to assess the effect of antiviral treatment on the improvement and complications.

METHODS

This study was conducted at an urban-academic emergency department during four influenza-seasons (2016-2019), retrospectively. Demographics, clinical findings, laboratories, metabolic disease analyses and serological features were extracted from the medical records. Treatments, complications and outcomes were also recorded.

RESULTS

A total of 114 children were included. The median age was 7.0 (min 1.25-max 17) years and 78.9% were male. The most common symptoms were leg pain (91.2%), anorexia (54.4%), fever (45.6%), sore throat (42.1%) and walking difficulty (32.5%). On admission, the median creatine phosphokinase level was 3332 IU/L (range, 1634-50 185), median aspartate aminotransferase 107 U/L (range, 38-1798). In the multiplex polymerase chain reaction analysis, 40.4% influenza B, 36.8% influenza A, 7.8% adenovirus, 7.8% parainfluenza virus, 5.3% rhinovirus, 5.3% respiratory syncytial virus and 1.8% Mycoplasma pneumoniae were detected. Rhabdomyolysis was developed in 6.7% and acute renal failure was seen in two patients. Oseltamivir was given in 44 (38.6%) patients who had influenza A/B. Metabolic disease screening tests were performed in 33.3% of patients and metabolic diseases were detected in 4 (3.5%) patients. The median recovery time was lower in patients with oseltamivir treatment (4 (min 2-max 5) - 5 (min 3-max 10) days) (P < 0.001).

CONCLUSION

Rhabdomyolysis is more common in BACM due to the influenza A virus. The early use of oseltamivir treatment was significantly associated with a shorter recovery time.

A crawling case of benign acute childhood myositis

Benign acute childhood myositis is a relatively uncommon complication of viral illness, particularly influenza A and B infections. In this abstract, we present a case report of benign acute childhood myositis secondary to influenza. On presentation, he was ill-appearing, febrile and had significant calf pain that limited mobility. Examination revealed mildly erythematous throat and bilateral calf tenderness with pain on dorsiflexion bilaterally. A respiratory virus panel was positive for influenza A subtype H3 and he was found to have an elevated creatine phosphokinase. He was diagnosed with benign acute childhood myositis secondary to influenza type A infection and symptoms gradually resolved following supportive management. Management involves oral hydration, pain management, and follow-up to ensure resolution. Extensive laboratory evaluation and hospitalization are often unnecessary. Benign acute childhood myositis is self-limiting with an excellent prognosis and should be included in the differential for a child who develops difficulty walking, particularly when presentation follows a respiratory infection.

Don't Forget the Flu - Determining the Etiology of Infective Myositis in a Child: A Case Report

Introduction

Infective myositis is an acute, self-limited condition, rarely occurring in children with recent viral infections. The condition is often overlooked by emergency physicians when endeavoring to exclude other diagnoses included in the differential. Diagnosis of the condition can be difficult when based purely on clinical presentation because it shares symptoms with much more concerning neurological illnesses. A few simple laboratory tests are indicated to reach the correct diagnosis.

Case Report

The following case report describes a three-year-old female diagnosed with a recent upper respiratory tract infection presenting to the emergency department with complaints of fatigue and inability to walk. She was diagnosed with an influenza-like illness three days prior by her pediatrician, the symptoms of which had mostly resolved by the time of presentation.

Conclusion

Muscle weakness and abnormal, uncoordinated gait with an acute upper respiratory tract infection in a child may be cause for concern, prompting unnecessary work-up. Emergency physicians should be aware of the signs and symptoms of influenza-associated infective myositis in children, especially during influenza season.

Burden of influenza B virus infection and considerations for clinical management

Influenza B viruses cause significant morbidity and mortality, particularly in children, but the awareness of their impact is often less than influenza A viruses partly due to their lack of pandemic potential. Here, we summarise the biology, epidemiology and disease burden of influenza B, and review existing data on available antivirals for its management. There has long been uncertainty surrounding the clinical efficacy of neuraminidase inhibitors (NAIs) for influenza B treatment. In this article, we bring together the existing data on NAIs and discuss these alongside recent large randomised controlled trial data for the new polymerase inhibitor baloxavir in high-risk influenza B patients. Finally, we offer considerations for the clinical management of influenza B, with a focus on children and high-risk patients where disease burden is highest.

Benign acute childhood myositis: importance of early recognition

Cases of children presenting with limb or joint pain are relatively common and are due mainly to benign conditions. Early diagnosis will help reduce unnecessary invasive investigations so, although a relatively rare condition, benign acute childhood myositis (BACM), which presents with acute lower limb pain and an isolated rise in creatine kinase, should be considered. BACM is characterised by an infiltration of viruses into calf muscle fibres, 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. This article discusses the management of a 10-year-old boy with a classical presentation of BACM, alongside differentials and management for clinician consideration.