Acute Hematogenous Osteomyelitis

Abstract

1. Dennis A. Conrad, MD* 1. *Professor of Pediatrics and Associate Chairman for Continuing Medical Education, Department of Pediatrics/Division of Infectious Diseases, University of Texas Health Science Center at San Antonio; Medical Director, Infection Control, CHRISTUS Santa Rosa Children's Hospital, San Antonio, Tex. After completing this article, readers should be able to: 1. Describe the pathophysiology of acute hematogenous osteomyelitis. 2. Correlate most common infectious causes of osteomyelitis with the age of the patient. 3. Recognize the typical clinical manifestations of acute hematogenous osteomyelitis. 4. Explain the appropriate use of ancillary information obtained by laboratory determinations and imaging studies to establish the diagnosis of acute hematogenous osteomyelitis. 5. Discuss the medical and surgical principles of management in the treatment of acute hematogenous osteomyelitis. The most common type of osteomyelitis, an infection of bone, that occurs in children is acute hematogenous osteomyelitis. Infection initially is established in the metaphyseal region of tubular bones, beginning as a metaphysitis following seeding by bacteria. The appendicular skeleton is the most common site of osteomyelitis. The lower extremity, especially the femur, is involved more often than the upper extremity, where the humerus is most likely to be infected. The pelvic bones or clavicles are less likely to be involved than the long bones of the extremities. The most common bone involved in acute hematogenous osteomyelitis in children is the femur. The axial skeleton is less likely to be the site of acute hematogenous osteomyelitis. Manifestations of osteomyelitis involving the axial skeleton are most commonly discitis, vertebral osteomyelitis, and infection involving the ribs and cranial bones. In most cases, the preceding bacteremia leading to acute hematogenous osteomyelitis is cryptic and asymptomatic, although osteomyelitis can be a focal complication of clinically symptomatic bacteremia and even overt septicemia. The nidus of infection begins in the valveless sinusoidal loops of the venules at their reflection at the epiphysis and is attributed to slow and nonlaminar blood flow through this vascular …