Primary pyomyositis and disseminated septic pulmonary emboli: a reactivated staphylococcal infection?

Abstract

Staphylococcal pyomyositis is a severe invasive soft tissue infection with high mortality rate that is increasingly being recognized even in temperate climates. In most cases predisposing factors are identified that include either source of skin penetration or/and impaired host immunocompetence. A case of primary, community-acquired pyomyositis of the left iliopsoas muscle in a 59-year-old immunocompetent woman, which was complicated with septic pulmonary emboli within 24h after hospital admission, is presented. The patient was subjected to abscess drainage under computed tomography guidance. Both pus aspiration and blood cultures revealed methicillin-susceptible Staphylococcus aureus. Given the absolute absence of predisposing factors and a remote history of staphylococcal osteomyelitis in the same anatomical region 53 years ago, reactivation of a staphylococcal soft tissue infection was postulated. Systematic review of the literature revealed a few interesting cases of reactivated staphylococcal infection after decades of latency, although the exact pathophysiological mechanisms still need to be elucidated.

Secondary myopathy due to systemic diseases

“…Pyomyositis of the iliopsoas muscle may be complicated by septic pulmonary embolism . These patients may require abscess drainage under CT‐guidance . Presence of intramuscular hemangiomas seems to predispose for pyomyositis, as reported in a 4‐year‐old child with fatal meningitis .…”

“…The main etiologic agent of bacterial polymyositis is Staphylococcus aureus . Staphylococcal pyomyositis is a severe infection with high mortality being increasingly recognized in temperate climates . Pyomyositis may originate from a focal infection such as arthritis, sacroiliitis, a spinal abscess, or from bacteremia or sepsis.…”

“…Pyomyositis may be diagnosed with ultrasound and culture of the aspirate . Pyomyositis of the iliopsoas muscle may be complicated by septic pulmonary embolism . These patients may require abscess drainage under CT‐guidance .…”

“…A rare cause of systemic myositis may be infection with campylobacter jejuni . Predisposing factors include skin penetration or impaired host immunocompetence (HIV‐1, transplant recipient) .…”

Obturator internus pyomyositis manifested as sciatica in a patient with subacute bacterial endocarditis

“…[3,11–13] The infection usually affects the extremities and pelvic muscles. [3,7,11] Sciatica cause by pyomyositis of the piriformis or gluteal muscles has been reported in a few patients.…”