**Neonatal Osteomyelitis**

**Neonatal Osteomyelitis**

Lidia Decembrino, Nunzia Decembrino and Mauro Stronati Mauro Stronati Additional information is available at the end of the chapter

Lidia Decembrino, Nunzia Decembrino and

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.69675

#### **Abstract**

Osteomyelitis in neonates is relatively uncommon, but burdened with an increased hos‐ pital stay and possible long‐term sequelae if not diagnosed on time. It differs from that of older children for etiology, clinical and radiological findings, and treatment. Due to anatomic contiguity, osteomyelitis may coexist with septic arthritis. Soft‐tissue swelling or joint effusion is often associated. Our aim is to review the literature to provide the most recent data related to epidemiology, clinical presentation, diagnosis, treatment, and outcome.

DOI: 10.5772/intechopen.69675

**Keywords:** neonatal osteomyelitis, septic arthritis, antibiotics, imaging studies, micro‐organisms

#### **1. Introduction**

Osteomyelitis (OM) refers to an infection of the bone that affects around 8/100,000 children [1]. For neonatal OM, an estimated incidence of 1–7/1000 hospital admissions has been reported [2, 3]. Due to their immature immune response, neonates are more susceptible than older children. Preterm infants are at a higher risk because of frequent blood withdrawal, invasive monitoring, diagnostic and treatment procedures, parent's nutrition, ventilatory support, perinatal hypoxia and prolonged NICU stay [4–7]. The long bones are the most frequently affected sites, especially of lower extremities, femur and tibia. Sites less commonly involved include the upper limbs, the pelvis, the clavicle, and the rib [8]. The presence of interosse‐ ous collateral arteries makes vertebral bodies less susceptible to infarction from septic emboli and more able to clear bacteria secondary to septic embolization. This explains the low inci‐ dence of vertebral body infection in neonates compared to older children and adults [9]. Few studies have focused on race differences. In low‐risk neonates with OM, an accompanying

Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons

fracture should be considered [10]. Sternal OM is extremely rare, but has been reported [11]. Neonates are most vulnerable to multifocal infection [12, 13]. **Pathophysiology.** Osteomyelitis in neonates is usually due to hematogenous spread of bacterial infections or less frequently to direct inoculation as a result of a trauma or puncture wounds or surgery, infected cephalo‐ hematoma [14–16]. In preterm infants, direct injection of bacteria can result from heel or veni‐ puncture and artery or vein umbilical catheterization. Indirect contamination from a nearby infection, for example, cellulitis is also possible. Premature rupture of membranes, transpla‐ cental infection, and urinary tract infections has been described as risk factors too [17, 18]. A few cases of neonatal Gram‐negative germ osteoarthritis have been reported, associated with a vesico‐ureteral reflux (VUR) or hydronephrosis by the same microorganism [19, 20]. The most susceptible areas to haematogenous seeding of infection are metaphyseal of long bones, in particular the areas adjacent to the cartilaginous growth plate (physis) that is highly vascu‐ larized with slow intravascular flow. Abscess can result from the passage of bacteria through gaps from the sinusoidal veins to the capillaries into the tissue, where they are provided an ideal environment to grow. These abscesses frequently rupture into the joint [21]. Acute hae‐ matogenous OM and septic arthritis of the adjacent joint coexist in up to 76% of all cases as a result of a unique vascular anatomy characterized by the presence of vascular connections between the metaphysis and the epiphysis, particularly before the appearance of a secondary ossification center. Involvement of the shoulder or hip joints is noted when the intracapsular metaphyseal end of the humerus or femoral are involved from infection.

(MRSA), community‐acquired strains of methicillin‐resistant *Staphylococcus aureus* (CA‐ MRSA) and *Kingella kingae* have emerged as being relevant in recent years and are responsible for serious infections [28]. *Candida albicans* OM needs to be considered in neonates, especially if preterms with specific risk factors. The presentation is more subtle and subacute, even in the absence of fever and elevated inflammatory markers. The progression is prolonged. OM from *Haemophilus influenzae* type b (Hib) has declined significantly; thanks to the introduction

Neonatal Osteomyelitis

99

http://dx.doi.org/10.5772/intechopen.69675

Differential diagnosis may be difficult and cellulitis, septic arthritis, subcutaneous abscess, fractures, and bone tumors should be taken into account. CNS disease (cerebral hemorrhage), trauma, scurvy, and child abuse are to be considered in the case of pseudoparalysis. Allagui et al. [29] described a case of acute OM of the clavicle in a 30‐day‐old newborn, with clinical symptoms simulating obstetric brachial plexus palsy. Laboratory tests are necessary to con‐ firm a clinical diagnosis of OM. Neonates with OM may have a normal leukocyte count that is elevated in only half of the patients with or without thrombocytosis. The C‐reactive protein (CRP) and erythrocyte sedimentation rate (ESR) are almost always elevated (except in small bone infections). It is important to obtain blood, bone, or joint aspirate cultures if necessary, to identify the causative organism, before any antibiotics are given. Because OM usually is a consequence of sepsis, hence lumbar puncture should be considered. Any potential source of infection should be examined, including intravascular catheter tips. Serum procalcitonin may be used as a sensitive and specific marker in the diagnosis of acute OM [30] more suitable as an aid for rule‐in diagnosis rather than for exclusion. Its diagnostic performance is better for a lower cut‐off value compared to a conventional cut‐off of 0.5 ng/ml which is specific but less sensitive [31]. A bone biopsy is advisable if the patient does not respond to the standard

Imaging (computed tomography (CT) scan, radiography, bone scan, US and/or MRI) is used to identify the site of an infection, the presence of liquid collections for diagnostic aspira‐ tion and/or biopsy, to differentiate a unifocal from multifocal disease and to identify pres‐ ent or impending complications, such as joint or extradural involvement. Montgomery et al. [32] showed that the use of advanced imaging (CT scan, bone scan, and/or MRI) in infants younger than 4 months of age may shorten hospital stays, decrease the number of operative procedures required, and possibly limit infection‐related sequelae. MRI has become the gold standard to evaluate musculoskeletal infection. It has the capability of assessing the osseous, articular and muscular structures simultaneously and does not require ionizing radiation. In particular MRI plays an important role in defining the extent of soft tissue involvement, defin‐ ing drainable fluid collections and bone biopsy sites pre‐operatively and thereby decreasing

of the Hib vaccine.

therapy.

**5. Imaging studies**

**4. Differential diagnoses**
