Osteomyelitis and Septic Arthritis Flashcards
Infection begins in skin, passes through muscle/tendon, reaches bone
Contiguous spread
Devitalized bone acting as foreign body =
sequestrum –> chronic drainage, colonization, abx don’t reach bone
Risk factors for hematogenous spread
IV drug use IV lines (dialysis, cancer)
Presentation of osteomyelitis
Acute: pain, fever, pus, red/hot area
Chronic: drainage, non-healing ulcer, probe to bone
Metal device contaminated, spreads to bone
Surgical/trauma spread
Most common cause of septic arthritis
Bacterial (usually S. aureus but don’t forget Gonococcal)
Can also be viral, fungal, mycobacterial
Hematogenous likely organisms
Usually one organism
Usually S. aureus
May also be Coag - staph, gram - rods
Arthrocentesis in septic arthritis will show
High WBC (>50,000), High % neutrophil (>90%), high protein
perform crystal analysis to r/o
Risk factors for septic arthritis contiguous spread
Cellulitis, abscess, osteomyelitis next to joint, Diabetes
Blood infection reaches bone
Hematogenous spread
Labs for osteomyelitis
Inflammatory markers, High WBC
Risk factors for septic arthritis hematogeneous spread
IV drug use IV lines (dialysis, cancer) Sexual intercourse (gonococcal)
Contiguous likely organisms
Usually polymicrobial (travel via skin)
Usually S. aureus
Also streptococci, Coag - staph, gram - rods, anaerobes
Risk factors for contiguous spread:
uncontrolled diabetes
neuropathy
callus/foot deformity
Polymicrobial bloodstream infections are common in
IV drug users
