Septic arthritis of the sacroiliac secondary to suppurative pyomyositis

Abstract

Pyomyositis is a subacute suppurative bacterial infection of muscle, caused by hematogenous spread and sometimes accompanied by the formation of abscesses. Although, it is a disease classically observed in tropical areas, in recent years an increase in its incidence has been described in temperate countries, especially in immunosuppressed people.
Its most frequent etiological agent is Staphylococcus aureus. The most common locations are the quadriceps, buttocks, and iliopsoas, the association with septic arthritis and osteomyelitis being exceptional.
In the pediatric population, it usually affects healthy people and athletes, and its appearance is related to intense physical exercise or minor trauma that, in many cases, can go unnoticed. The clinical presentation of acute pyomyositis is usually insidious, and can occur without fever, but with local symptoms such as pain, swelling, and functional limitation. Drainage of the abscess, followed by the administration of antibiotics leads to complete recovery. Primary pyomyositis is rare, and the diagnosis is delayed due to the deep location of the muscle and because the symptoms can confuse the diagnosis with septic arthritis of the hip.
We present this case due to the difficulty of its diagnosis and the complications derived from the delay in its diagnosis.