Bone and Soft-Tissue Disorders
= acute / subacute / chronic infection of skeletal muscle
Organism: viruses, bacteria (including mycobacteria), fungi, parasites; S. aureus (77%)
Pyomyositis / Bacterial Myositis
Risk factors: underlying HIV infection (17%), strenuous activity, rhabdomyolysis, muscle trauma (hematoma as nidus for infection)
Others: skin infection, infected insect bite, injection of illicit drug, underlying diabetes mellitus
Location: usually single muscle; multiple in 1143%; quadriceps m. >gluteal m. >iliopsoas m. >upper extremity
Iliopsoas abscess: TB of spine (formerly), GI / GU infection (currently)
Stages:
CT:
Cx:
DDx: cellulitis (involvement of SQ tissue >muscle group)