Journal of Perinatology (2009) 29, 254–255 r 2009 Nature Publishing Group All rights reserved. 0743-8346/09 $32 www.nature.com/jp IMAGING CASE REPORT Osteopenia of prematurity, staphylococcal rib osteomyelitis

TE Herman and MJ Siegel Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO, USA

Journal of Perinatology (2009) 29, 254–255; doi:10.1038/jp.2008.204 the erythrocyte sedimentation rate was 10 mm hÀ1 (normal 0 to 20), and the C-reactive protein level was 42.7 mg lÀ1 (normal 0 to Case presentation 10). The alkaline phosphatase was 510 IU lÀ1 (normal 100 to A 770 g infant boy was born to a Gravida 1, para 0 mother by 310 IU lÀ1). Plasma calcium and phosphorus levels were normal. caesarean section following premature rupture of membranes. The infant had initial Apgars of 4 at 1 min, 6 at 5 min and 8 at 10 min. Denouement and discussion He was intubated immediately after birth and initially treated in an The patient underwent incision and drainage of the left chest wall outside hospital intensive care nursery until day 114 of life, when lesion adjacent to the ninth rib. The fluid obtained from this he was transferred to our neonatal intensive care unit because of persistent respiratory failure, bronchopulmonary dysplasia and retinopathy of prematurity (Figure 1). At the time of transfer the infant was found to have staphylococcal sepsis, which was treated with vancomycin. He subsequently developed and was treated for Candidal and Klebsiella urinary tract infections while in the hospital. At 2 months of life, diffuse and focal soft tissue swelling of the chest was appreciated and chest and rib radiographs were obtained. These were repeated 1 week later when swelling was more focal (Figure 2). Diffuse osteopenia, healing rib fractures and a focal expansile lytic lesion of the left ninth rib and right seventh were present. A chest wall sonogram was obtained (Figure 3) over the area of short tissue swelling. On the day of the sonogram the white cell count was 24 000, having been 15 000 3 weeks before,

Figure 1 Frontal film of chest at admission. The ribs and scapula are well Figure 2 (a) Frontal chest at 2 months of life, (b) Frontal chest 1 week later. mineralized. Minimal right upper lobe infiltrate is present. The skeleton has become demineralized. On the chest radiograph at 2 months of life the posterior rib margins and scapula are difficult to visualize. The end of the Correspondence: Dr TE Herman, Mallinckrodt Institute of Radiology, St Louis Children’s right seventh rib (black arrow) is expanded and there is a destructive lesion seen Hospital, Washington University School of Medicine, 510 South Kingshighway Blvd., St Louis, in the left ninth rib (white arrow). On the radiograph 1 week later, the ends of the MO 63110, USA. right seventh rib (R7) and left ninth rib (L9) are more expanded (white arrows). E-mail: [email protected] The cortex of both ribs is destroyed posteriorly. There is marked overlying soft Received 23 July 2008; accepted 1 August 2008 tissue swelling (curved white arrow). Splenomegaly is also present. Osteopenia of prematurity TE Herman and MJ Siegel 255

Figure 4 Frontal chest radiograph. After completion of therapy there is minimal residual deformity of the right seventh and left ninth ribs (arrows), but the osseous structures of the chest are now otherwise normal and well mineralized.

features include soft tissue swelling, tenderness and decreased motion. Neonatal osteomyelitis most frequently involves the humerus and femur.2 In both sites septic arthritis often accompanies the osteomyelitis and the infant frequently has swelling and marked decreased motion, referred to as pseudoparalysis in 95% of cases.3 Radiographic findings of osteomyelitis usually require 7 to 14 days to appear. The findings of osteomyelitis are focal lytic Figure 3 (a) Transverse and (b) longitudinal sonographic images of the chest lesion, particularly metaphyseal in long bones, periosteal reaction, wall over the area of soft tissue swelling. A well defined heterogeneous, hypoechoic soft tissue swelling. Treatment of acute osteomyelitis is drainage of mass (M) is present immediately anterior to the echogenic wall of the adjacent abscess cavities and intravenous antibiotics.3 (ninth) rib (R), consistent with a subperiosteal abscess. Osteopathy of prematurity is a multietiologic metabolic bone disease resulting in reduced bone mineralization and fractures. The most common risk factors are inadequate supply of calcium and subperiosteal abscess grew a pure culture of oxacillin-sensitive phosphorus, immobility, parenteral nutrition, diuretic or steroid Staphylococcus aureus, indicating acute osteomyelitis of the rib. therapy.4 Treatment is aimed at beginning enteral feedings as soon The osteopenia and rib fractures with slightly elevated alkaline as possible to allow efficient absorption of phosphate, and adequate phosphatase led to a diagnosis of osteopenia of the premature. The doses of Vitamin D. infant was treated with Vitamin D supplementation, high mineral formula (EPF 24) and 42 days of intravenous oxacillin. Mineralization returned to normal as did the alkaline phosphatase. References Cardiac sonography was repeated at intervals and remained normal 1 Korakaki E, Aligizakis A, Manoura A, Hatzidaki E, Saitakis E, Anatoliotaki M et al. without endocarditis. The rib lesions and osteopenia resolved Methicillin-resistant Staphylococcus aureus osteomyelitis and septic arthritis in (Figure 4), and the infant was discharged in good condition. neonates: diagnosis and management. Jpn J Infect Dis 2007; 60: 129–131. Acute osteomyelitis is uncommon in neonates.1 The most 2 Weissberg ED, Smith AL, Smith DH. Clinical features of neonatal osteomyelitis. common organism isolated is S. aureus.1,2 Factors which may Pediatrics 1974; 53: 505–510. 3 Knudsen CJM, Hoffman EB. Neonatal osteomyelitis. J Bone Joint Surg 1990; 72B: predispose to the development of acute osteomyelitis in neonates 846–851. are prematurity, omphalitis, umbilical catheterization, prolonged 4 Harrison CM, Johnson K, McKechnie E. Osteopenia of prematurity: a national survey and 1–3 hospitalization, pneumonia or meningitis. Common clinical review of practice. Acta Paediatr 2008; 97: 407–413.

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