11.5 · Bone disorders: Osteomyelitis

Osteomyelitis

Infectious bone disease

Exogenous osteomyelitis

Most common form; pathogens enter the joint through fractures, penetrating wounds, bites, surgery, or diabetic foot infection

Hematogenous osteomyelitis

Pathogens are carried in the blood from a site of infection elsewhere in the body; usually in infants, children, and the elderly

Primary causative organism of osteomyelitis

Staphylococcus aureus, though also other bacteria, fungi, parasites, and viruses

Site of hematogenous osteomyelitis in children

Metaphyseal region close to the growth plate in long bones, where blood flow favours bacterial attachment

Sequestrum

Dead bone in the cortex after purulent exudate within bone and beneath periosteum cuts off blood supply

Involucrum

New layer of bone laid down by osteoblasts on top of the sequestrum after lifting of the periosteum

Osteomyelitis site in adults

Usually the axial skeleton, since long bones no longer have conditions favouring bacterial attachment

Osteomyelitis manifestations

Pain and loss of movement of the affected area, with systemic bacteremia signs of chills and fever

Osteomyelitis complication

Can become chronic with established abscesses in bone that are very difficult to treat

Osteomyelitis treatment

Antibiotics, debridement, and drainage of pus