**5.1. Clinical signs and symptoms**

In general, two distinct clinical syndromes have been postulated to be associated with neonatal osteomyelitis: 1) a benign form, with little or no evidence of infection other than local swelling, and 2) a severe form, with the predominant manifestation of a sepsis-like syndrome with multiple bone sites being noted as manifestations [28]. In neonates, almost half of all cases involve two or more bones.

**Figure 1.** Anatomic depiction of blood supply to the epiphysis and metaphysis in the developing bone that influences the progression of osteomyelitis in the neonate (modified and redrawn from Kaye JJ et al, [53]).

Clinical symptoms and signs of osteomyelitis in the neonate are at first frequently unspecific and mild. They may include temperature instability, feeding intolerance, irritability or reduced movement, frequently giving rise to the suspicion of secondary sepsis. Fever is a rare condition that could be explained by a rather poorly developed immune system. As the disease progresses, more specific signs may become present, including disability, local swelling or erythema. Focal tenderness over a long bone should catch the physician's attention. In some cases subcutaneous abscess formation prompts the diagnosis of osteomyelitis. Hip, knee and shoulder are most frequently involved [7,28,29].
