Osteomyelitis in hospitalized children with chickenpox: imaging findings in four cases

The most common complications of chickenpox are skin and soft-tissue infections. Pneumonia and CNS involvement occur less often, and skeletal complications are considered rare. The purpose of this study was to evaluate the imaging findings of osteomyelitis in children after chickenpox.

We retrospectively reviewed the records of children admitted to our institution because of chickenpox and analyzed the imaging findings in those who had skeletal involvement. Ninety-seven patients were admitted between January 1991 and January 1993 because of chickenpox or a complication thereof. Four previously healthy patients, three boys and one girl, between 1 and 6 years old had osteomyelitis. Staphylococcus aureus was isolated from bone in one patient, and group A beta-hemolytic streptococcus was isolated from blood cultures in another. No organism was grown in the other two; necrotic bone was recovered from one lesion and the other healed with periosteal formation of new bone typical of osteomyelitis. All patients were treated with IV antibiotics, and their recoveries were uncomplicated.

Conventional radiographs showed loss of fat planes in three patients and destruction of bone in two. Bone scintigraphy showed increased uptake of radionuclide in early and late phases in three patients. Uptake in one case was extensive, with a central area of relatively little uptake corresponding to a subperiosteal fluid collection. CT in two and MR imaging in one showed subperiosteal fluid collections surrounding the involved bones in association with bone and marrow changes.

Osteomyelitis was the fourth most common complication of chickenpox in our series. The appearances on conventional radiographs and scintigrams are indistinguishable from those of typical bacterial osteomyelitis. However, CT and MR imaging showed subperiosteal fluid collections in three of four patients, an appearance only occasionally seen with typical osteomyelitis.