0521779407-B01 CUNY1086/Karliner 0 521 77940 7 June 4, 2007 20:52
Bacterial Arthritis 215■Immunosuppressed conditions: immunosuppressive medications,
HIV, diabetes mellitus
■IV drug abuse
Sign & Symptoms
■Abrupt onset of inflammatory arthritis, monoarticular 80–90%
■Any joint possible; knee most often in adults & hip frequent in chil-
dren
■Joint pain, moderate to severe; worse w/ motion
■Marked limitation of active & passive range of motion
■Distinguish septic bursitis (eg, prepatellar or olecranon) from true
joint sepsis
■Systemic signs & symptoms of infection: fever (∼60%), chills (∼10%)
■Presentation varies w/ age/risk factors & organism involved
➣Children: younger–systemic symptoms w/ high fever, often asso-
ciated osteomyelitis; hip often involved, held in flexion; H.
influenzae common in younger children (incidence declining
due to vaccination)
➣Adults: lower extremity joints especially
➣Elderly: gram-negative bacteria a concern
➣Prosthetic joint infections: early after surgery–acute signs &
symptoms (Staphylococcus sp & Streptococcus sp), late infec-
tions more indolent
➣N. gonorrhoeae: most common form of infectious arthritis (∼1%
of patients w/ GC); vesicopustular or hemorrhagic skin lesions
often present; monoarthritis, oligoarthritis, migratory arthritis,
tenosynovitis possibletests
Lab Tests
■CBC: leukocytosis w/ shift to left
■Elevated ESR & CRP
Specific Diagnostic Tests
■Arthrocentesis required: examine for cell count, crystals, Gram stain
& cultures for routine & anaerobic bacteria, consider mycobacterial
& fungal smears & cultures
■Joint fluid inflammatory: WBC typically >50,000 cells/cc, >80%
neutrophils; glucose less than half serum level
■Synovial fluid Gram stain often positive (50–70%), but not sensitive
(60%) for presence of bacteria; culture diagnostic (positive in 70–
90% of cases but only 10–50% w/ N. gonorrhoeae)