Osteomyelitis Flashcards
Define Osteomyelitis
Inflammatory condition of bone caused by an infecting organism
Aetiology of Osteomyelitis
Haematogenous spread of infection, from direct inoculation of micro-organisms into bone, or from a contiguous focus of infection
Most common is S. aureus
Others: streptococci, enterobacteriaceae, anaerobic bacteria
Children - S. aureus, group B strep
Sickle cell - Salmonella spp
Older children - mycobacterium TB + salmonella
Risk factors of osteomyelitis
Previous osteomyelitis IV drug misuse (often involves long bones or vertebrae) Diabetes HIV infection Recent surgery Distant or local infections Sickle cell anaemia Rheumatoid arthritis CKD Immunocompromise URTI or varicella
Symptoms of Osteomyelitis
Limp or reluctance to bear weight (esp. in children)
Non-specific pain (1-3 months duration)
Malaise and fatigue
Local back pain + systemic symptoms (worsened by physical activity | may radiate to the abdomen, hip, leg, scrotum, groin
Fever
Limb deformities
Signs of Osteomyelitis on examination
Paravertebral muscle tenderness
Local inflammation, tenderness, erythema or swelling
Spinal cord or nerve root compression signs
Scars, fracture fixation
Reduced range of movement
Reduced sensation (diabetic foot infection)
Limb deformity
Tenderness to percussion
Meningitis
Investigations for osteomyelitis
Do NOT delay treatment waiting for results
Bone sample + biopsy: positive for infection or shows a tumour/granulomatous disease
FBC: raised WCC acute, normal chronic
ESR/CRP: raised in acute, normal chronic
Cultures: may be positive
X-ray affected area: Normal initially -> osteopenia 6-7 days after infection, bone destruction, periosteal thickening, joint effusion -> intra-medullary scalloping, cavities and “fallen leaf” sign
PCR: may be positive for infection that has not come up on cultures
Histology: May identify infecting organisms or acute or chronic inflammatory cells, dead bone, active bone resorption, small sequestra, or malignancy
