Osteomyelitis

Osteomyelitis is an infection involving bone, caused by bacteria in most cases. It may be severe, and it may affect any bone. The pathogen may enter the bone directly (non-hematogenous osteomyelitis), usually after trauma or wounds, or from the blood (haematogenous osteomyelitis).

Acute osteomyelitis develops within days or weeks. It's most common in children < 5 years, where haematogenous spreading of S. aureus is the most common cause. It also occurs in adults, where direct spread from a trauma, ulcer, or from haematogenous spreading after IV drug use is the most common cause.

Chronic osteomyelitis is a form of osteomyelitis that develops insidiously over months or years. It's usually related to bone ischemia or necrosis, due to how ischaemic or necrotic bone is not reached by antibiotics and the immune system, proving grounds for a chronic infection. Chronic osteomyelitis results in bone destruction and sequestrum formation. It's difficult to treat and it often recurs. In adults, chronic osteomyelitis is a common complication of acute osteomyelitis.

Clinical features

Symptoms include bone pain and fever.

Diagnosis and evaluation

Acute phase reactants are usually elevated and leukocytosis is usually present. Blood culture must be obtained. Bone biopsy and subsequent bone culture is the gold standard for diagnosis but is not always necessary, if the diagnosis can be made with reasonable certainty without it.

Imaging

Conventional radiography may not visualise pathology in the first 2 weeks of the disease. If the symptoms have lasted <2 weeks, CT or MRI is indicated. If it has lasted more than 2 weeks, radiography is sufficient and will show osteolysis, periosteal reaction, and bone destruction.

Management

Management is usually conservative, with broad-spectrum IV antibiotics. In refractory cases or cases where there is an abscess, surgery may be necessary.

Brodie abscess

Brodie abscess is a cystic region of pus and necrosis encapsulated by a rim of sclerotic bone. It occurs in the setting of chronic osteomyelitis in the metaphysis of long bones. It typically affects the distal tibia and is relatively more common in younger patients. It's managed with surgical opening, antibiotics, and autologous bone implantation.

Sclerosing osteomyelitis of Garré

Sclerosing osteomyelitis of Garré is a form of chronic (bacterial) osteomyelitis which lacks signs of active infection. It causes sclerosis and bony proliferation. It typically affects children and young adults, usually localised to the mandible secondary to a dental infection, but it can also affect the metaphysis or diaphysis of long bones. It's managed by surgery and antibiotics.