Osteomyelitis

Osteomyelitis In-depth

Etiology

Osteomyelitis is almost always caused by infection with a microorganism which is capable of producing pus (pyogenic). Depending upon the virulence of the microorganism and the resistance of the host, osteomyelitis may be an acute or chronic infection.[2]

Epidemiology

Non-specific Infection
Numerous reports show that 90% of cases of osteomyelitis are caused by Staphylococcus aureus.
The remaining 10% are due to: Streptococci, Pneumococci, Meningococci, and Salmonella or Colon bacilli
Osteomyelitis can occur at any point in ones life but it more often occurs between the ages of three and fifteen years, which is the period of most active bone growth.
Osteomyelitis affects males more than females by a ratio of 3:1.
Osteomyelitis typically affects long bones.[2]

Types of Osteomyelitis

Acute Osteomyelitis (Occurs mostly in children who may develop chronic osteomyelitis if untreated)
Chronic Osteomyelitis (Occurs in adults)

Bone Distribution (click image)

[2]

Pathogenesis (click image)

Pyogenic microorganism enter a metaphysis through a nutrient artery and then set up a focus of infection in the metaphyseal sinusoidal veins. Afterwards the infection spreads laterally and in the process begins to lift the periosteum. The accumulation of pus prevents proper circulation of blood through the cortex and results in death of the bone deprived of blood. This portion of dead bone is called sequestra. The elevation of the periosteum along with the infection of the subperiosteal space induces new bone formation which may eventually enclose the dead portion of the shaft. This in known as the involucrum. In some cases drainage hole or cloacae are observed on the involucrum to allow pus to drain out into the soft tissue.[2]

Morphological Characteristics

Note: Not all cases show all characteristics of Osteomyelitis

Treatments