osteomyelitis and septic arthritis

acute osteomyelitis

more common in children

sx onset with 2 wks post infection

chronic osteomyelitis

more common in adults

sx persist months or yrs post infection

risk factors for osteomyelitis

DM, PVD, open fx, IV drug use, catheter use, surgery

staph aureus

most common pathogen to cause osteomyelitis and septic arthritis

streptococci

second most common cause of septic arthritis

salmonella

osteomyelitis pathogen in those with sickle cell disease

N. gonorrhoeae

pathogen scene in sexually active pts

staph epidermidis

pathogen seen in prosthetic joint involvement

Mycobacterium tuberculosis

osteomyelitis pathogen seen in cases of vertebral involvement, Pott disease

also can cause septic arthritis

Pasteurella multocida

osteomyelitis pathogen seen in cases with dog/cat bites

Pseudomonas and Candida

pathogens seen in IV drug users and hospital infection

Borrelia burgdoferi

septic arthritis pathogen seen in endemic areas

hematogenous spread- osteomyelitis

originates or transported by blood

most common etiology in children

vertebrae most common site in adults

staph most common pathogen

contiguous spread

associated with surgery, trauma, wounds, poor vascularity

from adjacent skin (cellulitis) for septic arthritis

bacterial, mycobacterial, fungal

direct inoculation

penetrating injures, open fx, surgical contamination

biofilm formation

bacteria create biofilm during osteomyelitis making it difficult for abx to penetrate

osteomyelitis presentaiton

**draining sinus tract

swelling, erythema, tenderness, reduced ROM, ulcers

acute vs chronic osteomyelitis sx

lethargy, localized pain, erythema vs chronic pain

osteomyelitis labs

elevated CRP

elevated ESR

leukocytosis- present in acute, not chronic

biopsy and culture to dx

osteomyelitis imaging

initial test: x-ray, takes 10-14 days post infection to see findings

findings: periosteal rxn, lytic lesions, blastic findings, sequestrum, involucrum

MRI may show necrosis, abscess, sinus tracts

osteomyelitis tx

empiric abx, then guided by culture

surgical debridement

most common joints for septic arthritis

knee > hip > shoulder

what joint is commonly affected for IV drug users with septic arthritis

sternoclavicular joint

risk factors for septic arthritis

increased age, DM, RA, prosthetic joints, IV drug use, skin infection, alcohol use, sexual activity

septic arthritis presentation

fever, joint pain, joint is warm, erythematous, swollen

septic arthritis labs

elevated CRP

elevated ESR

arthrocentesis- WBC >50,000 is diagnostic**, gram stain and culture

arthrocentesis

best initial test for septic arthritis eval

can provide pain relief and valuable diagnostics like WBC, culture, crystals

straw color can indicate inflammation- meniscus tear or arthritis

red and icky- likely septic

septic arthritis imaging

xrays can give a baseline of joint damage

US can guide aspirations

MRI for deep joint effusion or osteomyelitis

septic arthritis tx

surgical emergency- I&D and IV abx (empiric then culture guided)

Since ESR and CRP are elevated with any inflammation, what do you use it for

can be used to monitor if tx is working