Ultrasonography of musculoskeletal infections in children

Ultrasonography is an important modality for evaluation of musculoskeletal infections in children because it is rapid, nonionising and very sensitive for (infectious) fluid collections and joint effusions. Moreover, the images are not degraded by metallic or motion artefacts (as with CT and MRI) and finally, ultrasonography offers the possibility of fine-needle aspiration to confirm the infectious nature of a fluid collection without unnecessary contamination of adjacent anatomical compartments. Ultrasonography should be combined with radiography because both imaging techniques are complimentary. The purpose of this article is to emphasise the role of ultrasonography in the diagnosis of various diseases in childhood, including cellulitis, subcutaneous abscess, necrotizing fasciitis, pyomyositis, infectious bursitis and arthritis, osteomyelitis, foreign bodies and infectious lymphadenitis. Along with conventional radiography, ultrasonography is a very valuable modality for early diagnosis and follow-up of musculoskeletal infections in children.     

Ultrasonography of acute musculoskeletal disease

With technical improvements (higher frequency and extended field-of-view sonography) the ability of ultrasound to detect pathology in the musculoskeletal system has been greatly increased. As in MRI, and unlike conventional radiography, soft tissue lesions in muscles, tendons and occasionally in joints can be shown directly. An advantage is real-time imaging of joints during stress. A disadvantage is limited demonstration of internal structures within joints. This paper provides an overview of various pathologies with emphasis on acute disorders. Received: 19 January 1999; Revised: 8 March 1999; Accepted: 27 April 1999     

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.     

Imaging-guided biopsy in musculoskeletal infections

Biopsies may be required in patients suspected to have musculoskeletal infections to confirm the diagnosis and also to identify the causative organism. Imaging-guided biopsies have gained increased acceptance to obtain various types of tissues for diagnosis. Under image guidance, biopsies are done percutaneously, usually under local anesthesia. They are relatively safe, and complications are significantly less compared with open biopsies. In this article, we review the planning, indications, technique, and complications of imaging-guided percutaneous biopsy performed for musculoskeletal infections.     

Role of ultrasound in musculoskeletal infections

Ultrasound is able to play a key role in the management of musculoskeletal soft tissue infections. It is an easily accessible imaging modality that can be used immediately after plain radiographs have been obtained. Quick diagnosis is essential in the clinical setting of musculoskeletal infection because delay can lead to significant morbidity. In addition to its diagnostic capabilities, US offers a safe, real-time, and convenient technique to perform immediately a guided-needle aspiration of any suspicious fluid collection. US provides the most efficient way to document quickly an infection of the musculoskeletal soft tissues and to identify the offending micro-organism.     

Magnetic resonance imaging of musculoskeletal infections

In summary, MRI has a high sensitivity for the detection of inflammatory disease involving the musculoskeletal system. Because of the usual anatomic pattern of involvement in the vertebral column, there is also a high specificity. In the appendicular skeleton and pelvis, it is unclear whether MRI can add to the sensitivity and specificity of radionuclide studies in uncomplicated cases of acute infection. However, it can be performed more rapidly and provides greater anatomic detail and delineation of the extent of marrow involvement than radionuclide studies. MRI can be used in both acute and chronic osteomyelitis to guide a diagnostic interventional test to the appropriate site. It is capable of excluding involvement of the medullary canal, and it is better than radionuclide studies for differentiating soft tissue infection with periostitis from osteomyelitis. It has only a limited role in the immediate postoperative period, and in the presence of metallic implants, an indium-labeled leukocyte scan may be more appropriate. Finally, it must be remembered that the current data base of MRI is small and that further refinement of its role in the evaluation of inflammatory processes will be forthcoming.     

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.     

Imaging of musculoskeletal and spinal infections in AIDS

The diagnosis of common and opportunistic infections in patients with HIV begins with clinical suspicion and involves relatively standard methodology. Musculoskeletal infection is sometimes the first manifestation of an HIV infection. In patients with HIV, the infections tend to be more advanced at presentation, occur in unusual sites, are caused by a wider spectrum of pathogens, and tend to show an inadequate or delayed response to therapy. The index of suspicion for musculoskeletal infections should be high when reviewing imaging studies of patients with HIV.     

Imaging of musculoskeletal disorders in children

A review of the year's literature on musculoskeletal disorders in infants and children includes many advances in imaging principles, especially MR imaging pulse sequences. We have not attempted to review these advances because the principles are essentially the same in children as in adults. We have confined this review to several topics including the importance of differentiating the findings in osteogenesis imperfecta from those in the abused child, limb-lengthening procedures in infants and children, the treatment of slipped upper femoral capital epiphysis, spinal anomalies, and skeletal abnormalities associated with cloacal exstrophy. A brief comment on cervical spine films in pediatric trauma patients is also included.     

Gadolinium-DTPA: value in MR imaging of extraspinal musculoskeletal infections

To determine if paramagnetic contrast agents can improve the detection, delineation, and characterization of extraspinal musculoskeletal infections (MSI) on magnetic resonance (MR) imaging, 42 patients with clinical suspicion of MSI underwent MR imaging before and after intravenous administration of gadolinium-DTPA. The lesions consisted of 27 proven infections and 15 noninfective conditions. Specificity and accuracy in identifying infective lesions averaged 80% and 84%, respectively, on precontrast studies and 80% and 89% on the enhanced examinations, with no statistically significant difference. Rim enhancement around abscess loculi was the only pathognomonic sign of infection seen in ten patients with chronic osteomyelitis and pyogenic or tuberculous infections. In 17 patients with acute osteomyelitis, brucellosis, or mycetoma, detection and delineation of the lesions were best on precontrast studies, while postcontrast examinations resulted in underestimation of the extent of abnormalities in all cases. We conclude that intravenous gadolinium-DTPA has limited usefulness in the MR evaluation of extraspinal MSI. Correspondence to: M. C. Haddad     

Ultrasonography of normal and abnormal appendix in children

Appendicitis is the most common acute surgical emergency of childhood. Since the original report by Puylaert in 1986, the use of ultrasonography in the diagnosis of appendicitis has been the subject of considerable study. Among the reported diagnostic criteria, the maximal outer diameter (MOD) of the appendix is accepted as the one of the most reliable criteria used to differentiate between a normal appendix and acute appendicitis. However, MOD measurement is subject to inaccuracies because luminal distention by non-compressible, non-inflammatory material such as fecal material, or increased maximal mural thickness due to reactive mucosal lym-phoid hyperplasia, or a medical cause due to a generalized gastrointestinal disease, such as Crohn’s disease, can cause the measurement to exceed the upper limits of normality. The aim of this article is to introduce the spectrum of ultrasonographic findings in the normal andabnormal appendix and eventually to reduce unneces-sary surgery in children.     

Ultrasonography of the genitourinary tract in children.

The author discusses the utility of ultrasound in investigating the genitourinary tract in neonates, infants, and children, and emphasizes the inter-dependence of ultrasonography and uroradiology.     

Ultrasonography of the kidney following renal biopsy in children

The frequency of renal and perirenal hematomas following percutaneous renal biopsy using a cutting needle was studied by means of ultrasonography in 30 children and young adults aged 3-16 years. Hematomas occurred in 64.5 percent of the biopsies but caused significant clinical symptoms in one patient only.     

Multifocal musculoskeletal tuberculosis in children: appearances on computed tomography

PURPOSE AND PATIENTS: The incidence of skeletal tuberculosis (TB), which once accounted for a majority of cases of extrapulmonary tuberculosis, has fallen significantly in recent years with the advent of effective drug therapy. Disseminated bone involvement in TB is very uncommon but it may still occur in countries where TB is endemic. We present the imaging findings of four children ranging in age from 2 to13 years, each of whom had multiple osseous stigmata of tuberculous infection. They presented to us over a period of 9 months. RESULTS AND CONCLUSION: Three of four children had calvarial lesions, with involvement of the bony orbit in one, and large abscesses were present in the chest wall and the mediastinum of another. Lesions along the dorsal spine were demonstrated in three cases, two of which showed epidural extensions. Bone lesions in the thoracic cage accompanying those in the spine were also seen in two children, one of whom had a solitary destructive focus in a rib distant from the site of vertebral involvement. Bone lesions involving the first metacarpal in one case and the scapular wing in two others are also described. The diagnosis in each of the cases was confirmed by the identification of epitheloid giant cells and caseous necrosis or tubercle bacilli in fine needle aspirates or on tissue culture studies.     

Renal parenchymal infections in children.

The excretion urogram-nephrotomogram is the most important imaging study in the diagnosis of renal parenchymal infection in children. If renal parenchymal infections are discovered before significant necrosis has occurred, vigorous treatment with appropriate parenteral antibiotics may result in resolution without the need for surgical drainage.     

Brain and meningeal infections in children

Summary The radiological changes found with infections of the brain and meninges are described. In most cases, the changes seen are not specific. — The value of the brain scan in demonstrating an abscess of the brain in a child is stressed.

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Hirn- und meningiale Infektionen bei Kinder

Zusammenfassung In der vorliegenden Arbeit werden die röntgenologischen Veränderungen beschrieben, die bei Infektionen des Gehirns und der Meningen beobachtet werden. In der Mehrzahl der Fälle sind diese Veränderungen nicht spezifisch. Der Wert der Hirnszintigraphie bei Hirnabszessen wird betont.

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Infections cérébrales méningées chez l'enfant. Considérations radiologiques

Résumé Les auteurs décrivent les modifications observées sur le cerveau et les méninges en cas d'infections. Dans la plupart des cas, les modifications notées ne sont pas spécifiques. Les auteurs insistent sur la valeur du Scanning dans le cas d'un abcès cérébral chez un enfant.