Pediatric Acute Osteomyelitis – Beyond Neonatal To 18 Months

Etiology:
— Hematogenous spread from asymptomatic or symptomatic bacteremia or by direct extension from skin wound
— Infection starts in marrow space with significant edema with proliferation of excess white blood cells and bacterial growth and through bony canals the infected fluid permeates outward and elevates the periosteum
— Most commonly Staphylococcus aureus
Imaging:
— Most commonly occurs at metaphysis and metaphyseal equivalents (apophyses, areas at the junction of bone and cartilage in flat bones) both of which are highly vascular with slow blood flow
— Before epiphyseal ossification centers appear (18 months) infection can cross growth plate into epiphysis as there is free communication between vessels of epiphysis and metaphysis and these transphyseal vessels can serve as a path of spread of infection from metaphysis to epiphysis
— Infection can spread into joint space or subperiosteal space or soft tissues or diaphysis of bone
— Most common regions involved are extremities and pelvis
— See continuous periosteal reaction, deep soft tissue edema
DDX:
Complications: Subperiosteal abscess, intramedullary abscess
Treatment: Antibiotics
Clinical: Multicentric in 10%

Radiology Cases of Acute Osteomyelitis – Beyond Neonatal To 18 Months

Radiograph of osteomyelitis beyond neonatal to 18 months — AP (left) and lateral radiographs (right) of the elbow show extensive periosteal reaction of the distal humerus and proximal ulna and an effusion of the elbow joint.

Radiograph of osteomyelitis beyond neonatal to 18 months — AP radiograph of the elbow shows a lucent destructive lesion in the distal ulna without periosteal reaction.

Radiograph of osteomyelitis beyond neonatal to 18 months — CXR at presentation (above) is unremarkable. AP radiograph of the left shoulder obtained 5 days later (below) shows displacement and destruction of the epiphysis of the proximal humerus.

Radiograph of osteomyelitis with Brodie's abscess — AP radiograph of the knee at presentation (upper left) shows lucent lesions of the metaphysis and epiphysis which show some interval healing on a followup AP radiograph of the knee taken 2 months later (upper right). The patient was lost to followup and did not complete antibiotic therapy and returned to clinic 2 years later and the AP radiograph at that time (lower left) shows a lucent sinus tract extending from the epiphysis to the metaphysis that persists on the next AP radiograph of the knee obtained 1 year later (lower right).