A Rare Full-Term Newborn Case of Rib Osteomyelitis with Suspected Preceding Fracture.

Acute osteomyelitis is uncommon in full-term neonates and occurs most frequently in those with critical illnesses, often following episodes of sepsis, skin infection, umbilical catheterization, urinary tract anomalies, or a complicated delivery. Here, we report a very rare case of acute rib osteomyelitis due to Staphylococcus aureus in a 13-day-old full-term male neonate. Ultrasonography (US) enabled diagnosis and revealed a coexisting costochondral junction rib fracture, which was not detected on routine chest radiography. Following a 29-day course of intensive parenteral antibiotic therapy, the patient was discharged in good health at 42 days of age without any scar formation. Due to its accessibility and safety, US can be a promising modality for detecting acute osteomyelitis in neonates with clinically highly suspected conditions in the neonatal intensive care unit setting, particularly those involving thin and mobile bones subject to respiratory motion. However, further studies are required to assess the utility of US in these cases and negative results. In low-risk neonates with osteomyelitis, an accompanying fracture should be considered.