TABLE 2.
Patient Characteristics by Arthritis Type
| Characteristics | Septic Arthritis | Lyme Arthritis | Other Arthritis |
|---|---|---|---|
| (N = 26) | (N = 32) | (N = 180) | |
| Demographics | |||
| Age, y, median (IQR) | 7.5 (5.6–10.7) | 7.9 (4.0–11.3) | 5.6 (4.0–10.7)a |
| Male sex, n/N (%) | 12/26 (46) | 14/32 (44) | 106/180 (59) |
| Race, n/N (%) | |||
| White | 22/24 (92) | 22/29 (76) | 122/163 (75) |
| African American | 0/24 (0) | 2/29 (7) | 4/163 (2) |
| Other | 2/24 (8) | 5/29 (17) | 34/163 (21) |
| Hispanic ethnicity, n/N (%) | 1/23 (4) | 2/22 (9) | 25/148 (17) |
| Presentation during peak Lyme season, n/N (%) | 16/26 (62) | 15/32 (47) | 74/180 (41) |
| Clinical history, n/N (%) | |||
| Presence of fever | 22/26 (85)a | 9/32 (28) | 69/180 (38) |
| Antibiotic pretreatment | 4/26 (15) | 1/32 (3) | 18/180 (10) |
| Inability to bear wt | 25/26 (96) | 24/26 (92) | 135/170 (79) |
| Laboratory studies | |||
| Peripheral WBC count (cells per μL × 103),a median (IQR) | 10.8 (8.5–12.8) | 10.5 (9.3–13.2) | 11.0 (8.8–14.6) |
| Peripheral ANC count (cells per μL × 103),a median (IQR) | 7.8 (5.4–9.5) | 6.8 (5.9–9.0) | 7.2 (5.0–10.0) |
| ESR, mm/h, median (IQR) | 59 (40–84)a | 36 (25–55) | 27 (14–47) |
| CRP, mg/dL, median (IQR) | 10.4 (7.2–17.1)a | 2.0 (1.2–5.0) | 1.8 (0.3–4.6) |
| Synovial fluid WBC count, cells per µL, median (IQR) | 126 130a (8300–209 332) | 53 954a (33 789–73 375) | 20 267a (2500–64 012) |
| Synovial fluid ANC, cells per μL, median (IQR) | 123 000 (78 392–190 440) | 50 290 (36 333–62 040) | 15 362 (1645–54 196) |
| Positive blood culture result, n/N (%) | 8/22 (36)a | 0/32 (0) | 4/180 (2) |
| Positive Gram-stain synovial fluid result, n/N (%) | 17/26 (65)a | 0/32 (0) | 0/180 (0) |
| Positive synovial fluid culture result, n/N (%) | 25/26 (96)a | 0/32 (0) | 0/180 (0) |
| Radiology studies performed, n/N (%) | |||
| Radiograph | 24/26 (92) | 30/32 (94) | 155/180 (86) |
| Ultrasound | 21/26 (81) | 29/32 (91) | 166/180 (92) |
| MRI | 12/26 (46) | 7/32 (22) | 49/180 (27) |
| Clinical management | |||
| Arthroscopic joint irrigation | 26 (100)a | 13 (41) | 55 (31) |
| Hospitalized | 26 (100)a | 26 (81) | 113 (63) |
a
Statistical difference using pairwise comparisons (P < .05).