Osteomyelitis is an infection of the bone. The three different modes of acquiring the infection are hematogenous, direct inoculation, and local invasion. In children, osteomyelitis is mostly hematogenous in origin and is usually caused by a bacterial infection. Risk factors for the hematogenous osteomyelitis in children are sepsis, hemoglobinopathies, and immunodeficiency disorders. The anatomic characteristic feature of the growing bone in children plays an important role in the pathogenesis and clinical feature of the disease. In children, the most common site of hematogenous osteomyelitis are in the long bones.

In children, osteomyelitis presents with nonspecific, systemic symptoms of low-grade fever and malaise, which is gradual in onset over several days to weeks. As the infection progresses, the patient presents with local symptoms of warmth, swelling, pain, and decreased mobility. The most common organisms causing hematogenous osteomyelitis in the normal host is Staphylococcus aureus. Other organisms causing hematogenous osteomyelitis are group A and B Streptococcus. Among children with sickle cell disease (SCD), Salmonella and other gram-negative organisms, such as Escherichia coli, can also cause osteomyelitis in addition to the typical organisms described above.

Osteomyelitis in SCD: Infections are a major cause of morbidity and mortality for patients with SCD. SCD patients are more susceptible to bacterial infections due to factors such as defective opsonins, and early loss of splenic function. These patients are more susceptible to osteoarticular infections, and osteomyelitis is one of the common infectious complications presenting in children with SCD.

Although S. aureus is the most common infectious agent causing osteomyelitis in the normal host, there still exists a controversy as to whether S. aureus or Salmonella is the most common infectious agent causing osteomyelitis in SCD patients. In their reviews, Burnett et al. and Chamber et al. have concluded that Salmonella is more common pathogen, followed
by S. aureus in causing osteomyelitis infection in SCD. This has important implications for both the diagnosis and treatment of the disease.