Primary Pyomyositis
Overview:
Primary Pyomyositis is a rare, subacute primary muscle infection most commonly as a result of a bacterium.
Most common muscles affected: large muscles
Quadriceps, Gluteal, Iliopsoas
Three stages of disease process:
1. Diffuse muscle infection
a. Insidious onset,progressive pain with low-grade fever, malaise, general muscle ache
2. Abscess formation
a. Tender soft tissue mass, muscle feels firm and wooden
b. Skin: swollen, erythematous, and warm
c. High fever, intense pain, swelling, erythema
3. Sepsis
a. Severe pain, local signs of infection, systemic sepsis
Causes:
Staphylococcus aureus has been found to be the cause in 77% of cases.
Streptococci, Escherichia coli, Salmonella enteritidus, Myocobacterium tuberculosis also causes in minority of cases.
Risk Factors:
Males, first and second decade of life.
Pathogenesis:
Infection due to transient bacteremia. Bacteremia episodes that affect the muscle. There is a blunt force trauma to muscle and or forceful contraction that creates a locus minoris for the bacterium.
Contraindications/Precautions:
Compartment syndrome, extension into adjacent tissue, sepsis, pericarditis, myocarditis, lung abscess, endocarditis, renal failure,
death.
Examination:
1. Walk with a limp or refuse to move hip.
2. Effected thigh held in flexion and external rotation.
3. Movements that put stretch of illopsoas are painful.
4. Hyperlordosis and scoliosos toward effected side.
5. Palpation: tender mass in the flank or just above inguinal ligament.
6. Deep, diffuse pain in the back, flank, or hip.
History
Trauma
Medications
Antibiotic treatment: cloxacillin, cloxacillin/aminoglycoside combo, first generation cephalosporin. Can be oral or IV. In case of abscess; always need of drainage
Diagnostic Tests/Imaging/Tests and Measures
Radiograph: first choice to rule out primary bone lesions
CT scan: Used for diagnosis
Ultrasonography: used for diagnosis
MRI: T2 weighted most useful
See Primary Myomyositis References
Primary Pyomyositis is a rare, subacute primary muscle infection most commonly as a result of a bacterium.
Most common muscles affected: large muscles
Quadriceps, Gluteal, Iliopsoas
Three stages of disease process:
1. Diffuse muscle infection
a. Insidious onset,progressive pain with low-grade fever, malaise, general muscle ache
2. Abscess formation
a. Tender soft tissue mass, muscle feels firm and wooden
b. Skin: swollen, erythematous, and warm
c. High fever, intense pain, swelling, erythema
3. Sepsis
a. Severe pain, local signs of infection, systemic sepsis
Causes:
Staphylococcus aureus has been found to be the cause in 77% of cases.
Streptococci, Escherichia coli, Salmonella enteritidus, Myocobacterium tuberculosis also causes in minority of cases.
Risk Factors:
Males, first and second decade of life.
Pathogenesis:
Infection due to transient bacteremia. Bacteremia episodes that affect the muscle. There is a blunt force trauma to muscle and or forceful contraction that creates a locus minoris for the bacterium.
Contraindications/Precautions:
Compartment syndrome, extension into adjacent tissue, sepsis, pericarditis, myocarditis, lung abscess, endocarditis, renal failure,
death.
Examination:
1. Walk with a limp or refuse to move hip.
2. Effected thigh held in flexion and external rotation.
3. Movements that put stretch of illopsoas are painful.
4. Hyperlordosis and scoliosos toward effected side.
5. Palpation: tender mass in the flank or just above inguinal ligament.
6. Deep, diffuse pain in the back, flank, or hip.
History
Trauma
Medications
Antibiotic treatment: cloxacillin, cloxacillin/aminoglycoside combo, first generation cephalosporin. Can be oral or IV. In case of abscess; always need of drainage
Diagnostic Tests/Imaging/Tests and Measures
Radiograph: first choice to rule out primary bone lesions
CT scan: Used for diagnosis
Ultrasonography: used for diagnosis
MRI: T2 weighted most useful
See Primary Myomyositis References
