bone and joint infections Flashcards
-septic arthritis -pott's disease -osteomyelitis -prosthetic bone + joint infection
Define septic arthritis
infectious agent in a joint leading to arthritis
Define osteomyelitis
infection and inflammation of bone marrow
Difference between acute + chronic septic arthritis
acute = PYOGENIC (fever + malaise) chronic= non pyogenic
Most common organism causing septic arthritis
staphylococcus aureus
- gram positive cooci
- 60% all cases
Pathogenesis is septic arthritis
infection in joint
- activates innate immune system - immune cells lead to pro-inflammatory cytokine release - joint destruction
- toxins + enzyme released by the pathogen itself - joint destruction
Most commonly affected joint in septic arthritis
knee joint = 50% cases
Biggest risk factors for septic arthritis in adults
- pre-exisitng arthritis = OA/RA
- trauma (surgery/joint replacement)
Biggest cause for septic arthritis in kids
idiopathic
followed by pre-existing infection
Synovial joint examination results in septic arthritis
SF- purlent (yellow-puss)
- high leukocytes count - gram stain positive (1/3rd cases) - low glucose (respiration for pathogens)
Blood test results in septic arthritis
- raised ESR or CRP (inflammation)
- neutrophilia (esp in kids)
Radiological changes in septic arthritis
-soft tissue swelling
-joint capsule distension
(>2wks before changes seen - joint destruction already occurred)
Differential diagnosis for septic arthritis
- gout
- pseudogout
- OA
- RA
Radiological features for septic arthritis
similar presentation to OA
- narrowing joint space
- bone erosions
- effusion
BUT CYST FORMATION + NO OSTEOPHYTES
Management of septic arthritis
- DRAINAGE - debridement + wash out (lowers bacterial load)
- broad spectrum antibiotics (prior to blood culture)
- blood culture
- gram specific antibiotics
Name some broad spectrum antibiotics
CI-PRO-FLOXA-CIN
PIPER-A-CILLIN