Infectious myositis
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Infectious myositis is an acute, subacute, or chronic infection of skeletal muscle.It is most often seen in young adults. Although viruses, bacteria (including mycobacteria), fungi, and parasites can cause myositis. The most common infectious agent is the bacterium, S aureus (77% of cases). Pyomyositis, or bacterial myositis, was once considered a tropical disease but is now seen in temperate climates, particularly with the emergence of HIV infection. Other risk factors for infectious myositis include rhabdomyolysis, muscle trauma, cellulitis, infected insect bites, injection of illicit drugs, and diabetes mellitus. Typically, only a single muscle is affected The most common site of infection is the quadriceps muscle. Drainage of the muscle abscess followed by administration of antibiotics remains the mainstay of treatment. Complications of untreated pyomyositis may include a compartment syndrome, progression of infection to osteomyelitis and septic arthritis, and even death.
Diagnosis
CT
- Enlargement and decreased attenuation of the affected muscle with effacement of surrounding fat planes.
- Intramuscular fluid collections may be observed
- Contrast material can help differentiate necrotic from viable musculature and to demonstrate a rim-enhancing abscess if present.
Patient #1
Patient #2
