OSTEOMYELITIS IN THE NEONATE

Neonatal Osteomyelitis

Osteomyelitis is a serious and potentially life-threatening condition affecting the skeletal system of newborns. The condition is relatively rare in neonates but occurs at higher rates in high-risk pregnancies, in preterm infants, and with the use of invasive devices. As a result of the anatomy and immature immune system of newborns, neonates differ in presentation, diagnosis, and management of osteomyelitis compared to patients of other age groups. An understanding of these differences will assist clinicians in the prompt diagnosis and management of this neonatal infection and lead to improved long-term outcomes.

Frequency of Multifocal Disease and Pyogenic Arthritis of the Hip in Infants with Osteoarticular Infection in Three Neonatal Intensive Care Units

OBJECTIVE

To describe the clinical features of osteoarticular infection in infants cared for in neonatal intensive care units (NICUs) and to assess the presence of multifocal infection.

STUDY DESIGN

Retrospective medical record review with structured data abstraction of infants with osteomyelitis or pyogenic arthritis or both in NICUs at 3 children's hospitals over a 29-year period.

RESULTS

Of the 45 cases identified, 87% occurred in prematurely born infants, with a median gestational age of 27.4 weeks (IQR, 26, 31 weeks). Median postnatal age at diagnosis of infection was 33 days (IQR, 20, 50 days). Osteomyelitis was present without joint involvement in 53% and with joint involvement in 44% of cases. Methicillin-susceptible Staphylococcus aureus (71%) was the predominant pathogen, despite prevalent methicillin-resistant S aureus in community-associated infections. More than 1 bone was infected in 34% of cases. The femur (in 50% of patients) was the most frequently involved bone and the hip (in 20% of patients) was the most frequently involved joint. Bacteremia persisted for 4 or more days in 54% of patients with a positive blood culture despite active antimicrobial therapy.

CONCLUSIONS

Among infants with osteoarticular infection in NICUs, multifocal disease is common and frequently is unsuspected. Search for additional sites of infection including the hip is warranted following the diagnosis of osteoarticular infection at a single site. Involvement of contiguous joints should be suspected in cases of osteomyelitis; conversely the presence of pyogenic arthritis usually indicates extant osteomyelitis in a contiguous bone.

Extended field of view magnetic resonance imaging for suspected osteomyelitis in very young children: is it useful?

BACKGROUND

Osteomyelitis is a challenging diagnosis for clinicians, particularly in very young children. At our institution, the magnetic resonance imaging (MRI) protocol in suspected osteomyelitis for children 5 years of age or younger includes a large field of imaging regardless of the clinical site of concern.

OBJECTIVE

To determine if extended field of view (FOV) MRI contributes important information in young children with suspected osteomyelitis.

MATERIALS AND METHODS

A retrospective study was performed including children 5 years of age or younger with suspected osteomyelitis from January 2011 to September 2015. All children underwent coronal fluid-sensitive MRI from neck to feet. Focused imaging was performed as necessary on abnormal sites depicted on survey imaging. Two radiologists reviewed the imaging findings, which were compared to the clinical outcome.

RESULTS

We studied 51 children with a mean age of 2.2 years (range: 21 days-5.5 years); 53% were boys. Osteomyelitis was depicted by MRI in 20 subjects (39.2%). Survey coronal fluid-sensitive imaging was accomplished by adding a single fluid-sensitive series in 1 child, 2 series in 31 children, 3 series in 16 children and 4 series in 3 children. Survey imaging added a median total time of 6:51 min to the examination (range: 2.29-20.54 min). Extended FOV imaging added important information in 11/51 subjects (21.6%), in 6 cases (11.8%) of infection and in 5 cases (9.8%) by suggesting alternative diagnoses.

CONCLUSION

The addition of extended FOV MRI in young children with suspected osteomyelitis added important clinical information in 21.6% of patients while only adding a median of 6:51 min to the examination. It is our experience that in children ≤5 years of age with suspected osteomyelitis, extended FOV imaging adds important information and may result in changes in management.

Clinical analysis of 17 cases of neonatal osteomyelitis: A retrospective study

Although acute osteomyelitis is rare in neonates, it might result in severe sequelae such as joint destruction and growth failure if it is not diagnosed and treated early. However, few studies have focused on the clinical features and treatment of this disease.A retrospective review of 17 cases of neonatal osteomyelitis, for which the patients underwent medical treatment alone or combined with surgery at the Children's Hospital of Zhejiang University School of Medicine between January 2009 and September 2016, was conducted. Medical treatment included the use of antibiotics and supportive care. Surgery was performed in cases with subperiosteal abscess (>1 cm) or clinical deterioration despite antibiotic therapy.All of the patients (11 men and 6 women) were term neonates. The main complaints were redness or swelling around the affected bone and fever. The most common sites were the femur (29.4%) and humerus (23.5%). There were 14 (82.35%) cases with positive cultures: Staphylococcus accounted for 71.43% (n = 10), followed by Salmonella (n = 1), Streptococcus pneumoniae (n = 1), Klebsiella pneumoniae (n = 1), and Escherichia coli (n = 1). X-rays (n = 14), ultrasound (n = 6), computed tomography (CT) (n = 5), or magnetic resonance imaging (MRI) (n = 7) were performed. Three of 14 x-rays were not pathological at the onset of the disease, while the positive rate of MRI in detecting osteomyelitis was 100%. Eleven of 17 cases underwent surgical drainage, and higher white blood cell (WBC) counts were found in patients requiring surgery (P < .05). The prognosis for all patients was good without severe sequelae with a mean follow-up period of 49.47 ± 23.43 months.In conclusion, the prognosis of neonatal osteomyelitis with early active treatment is good. MRI is advocated for detecting early osteomyelitis. Additionally, neonates with higher WBC count together with osteomyelitis have an increased risk for surgery.

US Evaluation of Juvenile Idiopathic Arthritis and Osteoarticular Infection

Juvenile idiopathic arthritis (JIA) and osteoarticular infection can cause nonspecific articular and periarticular complaints in children. Although contrast material-enhanced magnetic resonance imaging is the reference standard imaging modality, musculoskeletal ultrasonography (US) is emerging as an important adjunct imaging modality that can provide valuable information relatively quickly without use of radiation or the need for sedation. However, diagnostic accuracy requires a systemic approach, familiarity with various US techniques, and an understanding of maturation-related changes. Specifically, the use of dynamic, Doppler, and/or multifocal US assessments can help confirm sites of disease, monitor therapy response, and guide interventions. In patients with JIA, ongoing synovial inflammation can lead to articular and periarticular changes, including synovitis, tenosynovitis, cartilage damage, bone changes, and enthesopathy. Although these findings can manifest in adult patients with rheumatoid arthritis, important differences and pitfalls exist because of the unique changes associated with an immature and maturing skeleton. In patients who are clinically suspected of having osteoarticular infection, the inability of US to evaluate the bone marrow decreases its sensitivity. Therefore, the US findings should be interpreted with caution because juxtacortical inflammation is suggestive, but neither sensitive nor specific, for underlying osteomyelitis. Similarly, the absence of a joint effusion makes septic arthritis extremely unlikely but not impossible. US findings of JIA and osteoarticular infection often overlap. Although certain clinical scenarios, laboratory findings, and imaging appearances can favor one diagnosis over the other, fluid analysis may still be required for definitive diagnosis and optimal treatment. US is the preferred modality for fluid aspiration and administering intra-articular corticosteroid therapy. ^© RSNA, 2017.

Group A Streptococcal Suppurative Arthritis and Osteomyelitis of the Shoulder With Brachial Plexus Palsy in a Newborn

Osteoarticular infections in the newborn period are rare. A serious complication is paralysis of the affected extremity resulting from either pain or direct involvement of the nerve. We report a newborn with combined osteomyelitis and suppurative arthritis caused by Streptococcus pyogenes presenting with right brachial plexus palsy.

Pediatric osteomyelitis: a scintigraphic case-based review

This review presents techniques to optimize bone scintigraphy for evaluation of the spectrum of abnormalities associated with pediatric osteomyelitis, with an emphasis on the approaches to patient preparation and positioning and to interpretation. The diagnosis of pediatric osteomyelitis can be challenging for several different reasons. Bone scintigraphy is especially useful when the site of osteomyelitis is unclear. Other imaging modalities, including radiography, ultrasonography, and magnetic resonance imaging, all have advantages and may have a role in evaluating the condition of the child with osteomyelitis. Pathophysiologic considerations unique to children contribute to a different clinical presentation of osteomyelitis in the pediatric population than that seen in adults. In addition, patient movement degrades image quality substantially, which is an important consideration for imaging children. Neonates have a higher incidence of multifocal osteomyelitis, and they represent a unique subset of the pediatric population with separate considerations. Several examples illustrate techniques to optimize imaging, as well as show the spectrum of abnormalities associated with pediatric osteomyelitis. Careful attention to bone scintigraphic technique ensures that high-quality images can be obtained, which will allow confident diagnosis of pediatric osteomyelitis.

The bone scan

Bone imaging continues to be the second greatest-volume nuclear imaging procedure, offering the advantage of total body examination, low cost, and high sensitivity. Its power rests in the physiological uptake and pathophysiologic behavior of 99m technetium (99m-Tc) diphosphonates. The diagnostic utility, sensitivity, specificity, and predictive value of 99m-Tc bone imaging for benign conditions and tumors was established when only planar imaging was available. Currently, nearly all bone scans are performed as a planar study (whole-body, 3-phase, or regional), with the radiologist often adding single-photon emission computed tomography (SPECT) imaging. Here we review many current indications for planar bone imaging, highlighting indications in which the planar data are often diagnostically sufficient, although diagnosis may be enhanced by SPECT. (18)F sodium fluoride positron emission tomography (PET) is also re-emerging as a bone agent, and had been considered interchangeable with 99m-Tc diphosphonates in the past. In addition to SPECT, new imaging modalities, including (18)F fluorodeoxyglucose, PET/CT, CT, magnetic resonance, and SPECT/CT, have been developed and can aid in evaluating benign and malignant bone disease. Because (18)F fluorodeoxyglucose is taken up by tumor cells and Tc diphosphonates are taken up in osteoblastic activity or osteoblastic healing reaction, both modalities are complementary. CT and magnetic resonance may supplement, but do not replace, bone imaging, which often detects pathology before anatomic changes are appreciated. We also stress the importance of dose reduction by reducing the dose of 99m-Tc diphosphonates and avoiding unnecessary CT acquisitions. In addition, we describe an approach to image interpretation that emphasizes communication with referring colleagues and correlation with appropriate history to significantly improve our impact on patient care.

MR imaging of the neonatal musculoskeletal system

Experience in magnetic resonance (MR) imaging of the neonatal musculoskeletal system is rapidly increasing. The exquisite ability of MR to image the soft tissues, especially cartilage, without radiation is its key strength. Although it is not practical or sensible to undertake MR imaging in conditions in which radiography and ultrasound provide adequate information, MR is proving to be a useful adjunct and problem-solving tool in many neonatal musculoskeletal conditions.

Gram-negative neonatal osteomyelitis: two case reports

Neonatal osteomyelitis is a rare and challenging diagnosis, particularly in the early onset period. Neonatal osteomyelitis is predominantly caused by Staphylococcus aureus with single bone involvement. Here, we report two cases of neonatal osteomyelitis in premature infants caused by Klebsiella pneumoniae with multiple bone lesions. Both cases presented with sepsis and meningitis and were initially diagnosed by incidental findings on plain films, with follow-up bone scan imaging. In both cases, diagnosis was timely and treatment was successful. These cases highlight the need to include neonatal osteomyelitis in the differential diagnosis when late-onset or prolonged neonatal sepsis is present, particularly because long-term outcome is dependent on rapid diagnosis and initiation of treatment.

[Coagulase-negative staphylococcal osteomyelitis in preterm infants: a proposal for a diagnostic procedure]

Acute osteomyelitis, although a rare complication in neonates, is a diagnostic and therapeutic challenge. Successful treatment to avoid functional sequelae depends on early recognition of infection and rapid initiation of therapy. Although Staphylococcus aureus is the most common causative agent, coagulase-negative Staphylococcus (CONS), well known for bloodstream infection, can be involved in neonatal osteomyelitis. Risk factors of osteomyelitis include prematurity and invasive procedures, such as long-term central venous catheterization. We report on 3 cases of acute CONS osteomyelitis in preterm infants presenting with prolonged CONS bacteremia. Bacteremia persisted despite antibiotic treatment in accordance with antibiograms and despite removal of the intravascular device. All catheter cultures were negative and osteomyelitis was not located on the limb where the central catheter had been inserted in all cases. Osteomyelitis diagnosis may be difficult in neonates because of the paucity of clinical signs. In our observations, (99m)Tc scintigraphy was the key investigation for diagnosis and detection of multiple sites of bone infection. The place of this investigation is discussed in relation to other imaging techniques. These observations suggest that in the context of persisting CONS bacteremia, a secondary bone infection should be considered. Scintigraphy is a discriminating diagnostic tool.

Role of MRI in paediatric musculoskeletal conditions

The aim of this review is to discuss the indications and use of MR imaging (MRI) in the paediatric musculoskeletal system. After briefly reviewing basic technical considerations the MRI appearance of the most relevant congenital, inflammatory, infectious, ischemic, and posttraumatic skeletal conditions, as well as benign and malignant bone and soft tissue tumours that are typical for the paediatric age group will be presented.

[Neonatal infections of the bones and joints]

Neonatal osteoarticular infections remain rare, with an estimated incidence of 1 to 3 cases per 1000 admissions to Neonatal Intensive Care Units. It usually results from bacteraemia and may thus be induced by IV catheters. More rarely it is due to direct inoculation secondary to cutaneous damage, or extension of soft tissue infection. The particularity of bone vascularization in the newborn explains the frequency of abscess formation in the periosteum or in soft tissues. The main pathogen involved is S. aureus (3/4 of cases), followed by group B streptococci and enterobacteriacae. Infection consists mainly of localised and slowly progressing abscesses. However, multifocal and severe infection is possible, in particular when caused by an IV catheter. Ultrasonography is the best initial investigation, possibly leading to surgical care. Medical treatment must include 2 synergistic antistaphyloccocal antibiotics, possibly associated with cefotaxime. The outcome is generally favorable, but orthopaedic consequences may emerge if the growth plate is involved. Rare specific causes, such as syphilis or tuberculosis, should also be evoked, but the clinical context is generally helpful for the diagnosis.

Infections of the Skeletal System

Infections of the skeletal system are caused by a variety of organisms and generally occur through two routes, direct inoculation or hematogenous spread. Treatment requires long-term antimicrobial therapy with or without surgery to remove devitalized bone, inflammatory debris, foreign material, and necrotic tissue. This article reviews the causative agents,common diagnostics, and nuances of antimicrobial therapy commonly used to treat infection. It also reviews the major classifications of skeletal infections (hematogenous bone infections, bone infection from exogenous sources, and septic arthritis), with details covering pathophysiology,clinical presentation, treatment, and prognosis.

Musculoskeletal infections in children

Serious musculoskeletal infections in children include osteomyelitis, septic arthritis, pyomyositis, and necrotizing fasciitis. The epidemiology, pathophysiology, and microbiology of each of these infections are reviewed. Specific diagnostic studies and management strategies are discussed. Prompt recognition and treatment is emphasized to prevent potential long-term sequelae.

Acute hematogenous osteomyelitis in children: recognition and management

Acute hematogenous osteomyelitis is most common in children and has the potential to cause life-long musculoskeletal deformities. Most cases are caused by Staphylococcus aureus. Haemophilus influenzae type b (Hib) is now rare in countries that routinely use the Hib vaccine. Although magnetic resonance imaging is the preferred modality in localized disease, scintigraphy is often preferred as the first line of investigation because it helps to clarify the location of infection and exclude the presence of multifocal disease. Where the presentation is typical, there is no underlying disease, there is a low prevalence of community-acquired methicillin-resistant S. aureus (CA-MRSA), and there is a good response to antibacterial therapy, a diagnostic bone aspirate or biopsy is not necessary. The first-line antibacterial choice in most circumstances is a beta-lactamase-resistant penicillin. If CA-MRSA is suspected, the first-line options include clindamycin, the addition of an aminoglycoside or, rarely, vancomycin. In most patients, the total duration of therapy can be substantially shorter than the traditional 6 weeks, and oral therapy can be commenced after a brief course of intravenous antibacterials. We recommend 3 days of intravenous therapy followed by 3 weeks of high-dose oral antibacterials, provided there is no underlying illness, the presentation is typical and acute, and there has been a good response to treatment initially. Any deviation from this requires more intensive confirmation of the diagnosis (with imaging and/or biopsy or aspiration), and prolongation of intravenous therapy and total duration of treatment. Close monitoring and follow-up for at least 2 years are advised to detect complications.

MRI of the marrow in the paediatric skeleton

Magnetic resonance imaging (MRI) has greatly advanced evaluation of marrow diseases of the paediatric skeleton. As with many other aspects of paediatric radiology it is important to recognize the normal variations in the appearance of the marrow that occur in the growing child. These normal variations need to be differentiated from diseases and conditions that affect the marrow. This review describes the normal changes that occur in children with age, and the appearances of the pathological changes seen in infection, infiltration, haematological disorders, transplantation and radiation therapy.

Management of septic arthritis

Septic arthritis in children remains a serious disease with the potential for significant systemic and musculoskeletal morbidity. Staphlococcus aureus is the most common cause of bone and joint infections in all age groups. Microbial invasion of the synovial space occurs typically results from hematogenous seeding. Diagnosis in neonates and young infants can be difficult since the clinical signs are much less specific in these age groups. Early diagnosis by needle aspiration of the affected joint and prompt initiation of appropriate antimicrobial therapy in conjunction with drainage of the affected joint is critical to avoid destruction of the articular cartilage and prevent disability. Septic arthritis in infants and children should always be managed by a pediatrician in close consultation with an orthopedic surgeon. Empiric antibiotic regimens should always include adequate anti-staphylococcal coverage. Antibiotic treatment should be started with appropriate doses of intravenous antibiotics. Switch to oral antibiotic therapy can be made when patient demonstrates clinical improvement. A minimum of 3-4 weeks of therapy is recommended. Close follow-up is warranted to monitor the growth of the affected limb until skeletal maturity.

Imaging of osteomyelitis and musculoskeletal soft tissue infections: current concepts

The diagnostic imaging of osteomyelitis can require the confluence of multiple imaging technologies. Conventional radiography should always be the first imaging modality. Sonography is most useful in the diagnosis of fluid collections in a joint or in the extra-articular soft tissues but is not useful for evaluating presence of osseous infection. CT scan can be a useful method to detect early osseous erosion and to document the presence of sequestrum, foreign body, or gas formation but generally is less sensitive than other modalities for the detection of bone infection. Nuclear medicine and MRI are the most sensitive and most specific imaging modalities for the detection of osteomyelitis. Nuclear medicine is particularly useful in identifying multifocal involvement, which is common in children. MRI provides more accurate information of the local extent of the soft tissues and possible soft tissue abscess in patients with musculoskeletal infection.

Imaging of musculoskeletal infections

Imaging studies play a critical role in the diagnosis and management of musculoskeletal infections in children. Conventional radiography is usually the first imaging study performed with other imaging modalities as needed. Ultrasound is helpful in detecting joint effusions and fluid collections in the soft tissue and subperiosteal regions, and may guide localization for aspiration or drainage. CT can demonstrate osseous and soft tissue abnormalities and is ideal for detecting gas in soft tissues. Nuclear scintigraphy and MR imaging are valuable because of their high sensitivity. Scintigraphy is particularly useful in identifying multifocal involvement, which is an important consideration in neonatal osteomyelitis and CRMO. MR imaging provides accurate information on both the soft tissues and bones and is our imaging study of choice for evaluating the local extent of musculoskeletal infections.

Role of scintigraphy in musculoskeletal and spinal infections

Clinical findings are still the mainstay for suspecting the diagnosis of musculoskeletal infections, especially osteomyelitis. No single complementary imaging technique has 100% specificity and sensitivity for every case of musculoskeletal infection. Depending on the age of the patient, presence of orthopedic hardware, location of infection, underlying bone, and systemic conditions, the choice of imaging modalities must be tailored to the patient's condition. Plain radiographs are performed first and may be sufficient. In children, bone scan is highly accurate to diagnose osteomyelitis. Labeled leukocytes with complementary bone or bone marrow studies are recommended for orthopedic hardware or diabetic foot. Finally, gallium scanning is useful for the diagnosis of vertebral osteomyelitis. Current radiopharmaceuticals used for diagnosing infection also label inflammation. Newer products, as Infecton, should in the future allow better differentiation between infection and sterile inflammation.

Septic arthritis in children

Because of its seriousness, septic arthritis should be considered early in the differential diagnosis of any child presenting with joint inflammation. Physicians who care for children should be aware of the early signs and symptoms of septic arthritis and be aggressive about establishing the diagnosis so that treatment is not delayed. Early orthopedic consultation and a low threshold for performing arthrocentesis are prudent. Prolonged and appropriate antimicrobial therapy is warranted to achieve optimal results.