A patient with pyomyositis may present with a number of clinical findings that change as the infection progresses.
Clinical stages progressing over days to weeks:
(1) invasion (early)
(2) suppuration (evolving)
(3) systemic manifestations with fully developed abscess
Initially there is cramping with mild pain and tenderness in the involved muscle without fever.
This is followed by low-grade fever, swelling, and increasing pain with tenderness. The affected muscle becomes indurated and firm ("woody").
Finally the area becomes fluctuant with erythema and marked tenderness. The person may show signs of sepsis with fever, malaise and chills.
Local Findings |
Pain and Tenderness |
Fever |
Systemic |
Stage |
cramping |
mild |
none |
none |
invasive |
swelling and induration |
moderate |
low grade |
none |
suppurative |
fluctuant, erythema |
marked |
present |
present |
fully developed systemic |
Sometimes a patient may present acutely with systemic findings without preceding stages.
A CT or MRI scan can be helpful in establishing the diagnosis and determining the extent of involvement.
Differential diagnosis:
(1) muscle strain
(2) synovitis
(3) thrombophlebitis
(4) neoplasm
Specialty: Infectious Diseases, Surgery, general, Surgery, orthopedic