Changing spectrum of primary pyomyositis in North India

Abstract

Recent data have demonstrated the changing epidemiology of primary pyomyositis worldwide. Our hospital-based retrospective study investigated the clinical and microbiological spectrum of primary pyomyositis between 2013 and 2021 in PGIMER (Chandigarh), India. Over a quarter had predisposing conditions, mainly diabetes mellitus and immunosuppressive therapy. Fever, muscle pain, local swelling and breathlessness were the usual presentations, with quadriceps, iliopsoas and gluteal muscles commonly affected. Staphylococcus aureus was the predominant cause, with c.50% methicillin-resistant strains. Almost two-thirds presented with metastatic infection (stage 3 pyomyositis), frequently with septic lung emboli. Patients with methicillin-sensitive and resistant Staphylococcus aureus had a similar incidence of metastatic infection. In-hospital mortality was c.10% and was strongly associated with a high international normalised ratio. Primary pyomyositis remains a significant problem, with a dramatic increase in community-associated methicillin-resistant Staphylococcus aureus.

Keywords: Primary pyomyositis; Staphylococcus aureus; infectious myositis; methicillin-resistant Staphylococcus aureus; septic lung emboli; tropical.