Staphylococcus is the organism responsible for 90% of cases of acute osteomyelitis . Other organisms include Haemophilus influenzae and Salmonella; infection with the latter may occur as a complication of sickle cell anaemia.
Osteomyelitis can be due either to metastatic haem atogenous spread (e.g. from a boil) or to local infection. Malnutrition, debilitating disease and decreased immunity may playa part in the pathogenesis.
Chronic osteomyelitis may follow an acute infection.
Another variety of chronic osteomyelitis is due to infection being localized to form a chronic abscess within the bone (Brodie’s abscess). Patients may be asymptomatic for months or years or may have intermittent local pain. Treatment of osteomyelitis is with immobilization and antibiotic therapy with flucloxacillin and fusidic acid.
This is usually due to haematogenous spread from a primary focus in the lungs or gastrointestinal tract. The disease starts in intra-articular bone. The spine is commonly involved (Pott’s disease), with damage to the bodies of two neighbouring vertebrae leading to vertebral collapse and later abscess formation (‘cold abscess’). Pus can track along tissue planes and discharge at a point far from the affected vertebrae. Symptoms consist of local pain and later swelling if pus has collected. Systemic symptoms of malaise, fever and night sweats occur. Treatment is as for pulmonary tuberculosis (see p. 686) together with immobilization.