As more individuals were coronavirus disease 2019 (COVID-19) vaccinated, unexpected side effects appeared. Herein, we present the case of a 30-year-old
male patient with
myopathy in both
extremities after the second
dose of the Pfizer-BioNTech (
BNT162b2)
COVID-19 vaccine. Symptoms, swelling and
pain, started from the proximal upper and
lower extremities and extended to the distal parts. Although he underwent massive hydration, the
muscle enzyme level continuously increased. He complained of
dysphagia and
dysarthria.Microscopically,
muscle biopsy showed multifocal or scattered
macrophage infiltration and degenerated myofibers. In contrast to general
myopathy including inflammatory
myositis and
rhabdomyolysis,
vaccine-induced inflammatory
myositis shows a prolonged increase in
muscle enzyme levels and multifocal
macrophage infiltration with
necrosis of the
muscle fibers. Symptoms improved with
glucocorticoid and immunosuppressive
treatment. If vaccinated individuals experience severe and continuous
muscle pain and swelling, clinicians should consider
vaccine-induced inflammatory
myositis,
measure the
muscle enzyme levels, and perform
muscle biopsy for a definite
diagnosis.