Table 1.
Demographics and Clinical Presentation of Pyomyositis and Infectious Myositis
| Demographics and Clinical Information | Staphylococcal Species (N = 28) | Streptococcal Species (N = 7) | Culture-Negative (N = 16) | Other (N = 10) | Total (N = 61) | P Value |
|---|---|---|---|---|---|---|
| Age (mean ± SD) | 48 ± 16 | 47 ± 15 | 47 ± 21 | 52 ± 22 | 48 ± 18 | .94a |
| Male sex (No., %) | 24 (86%) | 3 (43%) | 8 (50%) | 5 (50%) | 40 (66%) | .02b |
| Body mass indexc (kg/m2) (mean ± SD) | 29 ± 4 | 27 ± 2 | 27 ± 3 | 27 ± 5 | 28 ± 4 | .49a |
| Diabetes mellitus (No., %) | 11 (39%) | 2 (29%) | 4 (25%) | 3 (30%) | 20 (33%) | .81b |
| Immunocompromising comorbidityd (No., %) | 3 (11%) | 1 (14%) | 1 (6%) | 5 (50%) | 10 (16%) | .03b |
| Clinical Presentation | ||||||
| Pyomyositis cases (No., %) | 24 (86%) | 5 (71%) | 8 (50%) | 6 (60%) | 43 (70%) | .06b |
| Myositis cases (No., %) | 4 (14%) | 2 (29%) | 8 (50%) | 4 (40%) | 18 (30%) | .06b |
| Intravenous drug use in past month (No., %) | 3 (11%) | 3 (43%) | 2 (13%) | 0 | 8 (13%) | .10b |
| Rigorous exercise in past month (No., %) | 3 (11%) | 0 | 1 (6%) | 0 | 4 (7%) | .88b |
| No. of days between symptom onset and presentation (median, range) | 7 (1–30) | 4 (2–21) | 3 (1–21) | 8 (1–30) | 5 (1–30) | .19a |
| Muscle pain (No., %) | 27 (96%) | 6 (86%) | 16 (100%) | 9 (90%) | 58 (95%) | .26b |
| Tenderness to palpation (No., %) | 18 (64%) | 5 (71%) | 13 (81%) | 6 (60%) | 42 (69%) | .60b |
| Strength or range of motion change (No., %) | 7 (25%) | 2 (29%) | 7 (44%) | 4 (40%) | 20 (33%) | .61b |
| Area of induration or palpable mass (No., %) | 9 (32%) | 2 (29%) | 3 (19%) | 3 (30%) | 17 (28%) | .86b |
| Subjective fever (No., %) | 13 (46%) | 5 (71%) | 7 (44%) | 5 (50%) | 30 (49%) | .70b |
| Malaise (No., %) | 11 (39%) | 3 (43%) | 5 (31%) | 6 (60%) | 25 (41%) | .57b |
| Night sweats (No., %) | 3 (11%) | 1 (14%) | 2 (13%) | 1 (10%) | 7 (11%) | 1.00b |
| Weight loss (No., %) | 3 (11%) | 0 | 0 | 1 (10%) | 4 (7%) | .55b |
| Altered mental status (No., %) | 6 (21%) | 0 | 2 (13%) | 2 (20%) | 10 (16%) | .66b |
| Temperature (mean ± SD, °F) | 100.0 ± 1.6 | 101.0 ± 2.2 | 100.0 ± 1.8 | 100.2 ± 2.3 | 100.1 ± 1.8 | .62a |
| White blood cell count (103/μL) (mean ± SD) | 15 ± 6 | 14 ± 4 | 12 ± 3 | 13 ± 6 | 14 ± 5 | .17a |
| ≥5% bands (No., %) | 6 (21%) | 3 (43%) | 1 (6%) | 1 (10%) | 11 (18%) | .18b |
| Blood culture positive (No., %) | 13 (46%) | 1 (14%) | 0 | 3 (30%) | 17 (28%) | .003b |
Abbreviations: SD, standard deviation.
aOne-way analysis of variance.
bFisher’s exact test.
cOne patient’s body mass index is missing from the streptococcal species group’s data.
dCirrhosis, person with human immunodeficiency virus, hematopoietic stem cell transplant, solid organ transplant, end stage renal disease, active malignancy, or receipt of immunosuppressive regimen.