Benign Acute Childhood Myositis During Influenza B Outbreak

Area of Science:

• Pediatrics
• Infectious Diseases
• Neurology

Background:

• Benign acute childhood myositis (BACM) is a common post-viral syndrome in children, typically following upper respiratory infections.
• It presents with severe calf pain, leading to difficulty walking, and is associated with elevated serum creatinine kinase and AST.
• BACM is generally self-limiting, resolving within a week.

Purpose of the Study:

• To describe a case series of BACM in Polish children during influenza outbreaks.
• To investigate the clinical presentation and workup of BACM.
• To evaluate the association between BACM and influenza B infection.

Main Methods:

• Retrospective case series analysis of children diagnosed with BACM in Poland during 2012/2013 and 2014/2015 influenza seasons.
• Clinical data, presentation, and diagnostic workup were reviewed.
• Serological testing for influenza B specific IgG antibodies was performed.

Main Results:

• A significant association was found between BACM and influenza B infection.
• Specific IgG against influenza B virus was detected in 83% of children with BACM.
• Influenza B was confirmed as prevalent during the studied epidemic seasons in Poland.

Conclusions:

• Influenza B is strongly associated with the development of benign acute childhood myositis in children.
• BACM diagnosis should consider recent influenza B infection, especially during outbreaks.
• Prompt recognition and supportive care are key for managing BACM.