Osteomyelitis of the sacrum

In the axial skeleton, osteomyelitis of the os sacrum is rare, although it occurs more frequently than tuberculosis of the sacrum. Secondary osteomyelitis as a complication of tumours, metastases or inflammatory processes of the adjacent areas is seen more often than primary sacral osteomyelitis.     

Diagnostic Features of Emphysematous Osteomyelitis

Emphysematous osteomyelitis (EO) is a rare, aggressive, and potentially fatal variant of osteomyelitis related to gas-forming organisms. Imaging plays a vital role in diagnosis. The purpose of this study was to describe a novel and distinct imaging sign of EO, by analysis of the imaging characteristics of 3 newly identified cases of EO as well as all reported cases in the literature. Literature review and retrospective study in 2 tertiary care medical centers was conducted. During the course of clinical care over the last year, we have observed 2 cases of EO. An Institutional Review Board approved 1-year systematic retrospective review of our institutional radiology information system identified 1 additional case of EO. We conducted a MEDLINE literature search to identify all published EO case reports using key phrases. The imaging in all published cases was reviewed. To address the specificity of imaging characteristics, we identified cases demonstrating variants of intraosseous gas that were not caused by EO. We found 31 individual case reports of EO via MEDLINE search. Of the published cases, 25 of the 31 cases contained images of sufficient extent and quality for image analysis. Including our 3 cases, a total of 34 cases were identified. Of the 34 cases, 28 had images of sufficient quality and extent to determine the presence or absence of the “pumice stone” pattern. The “pumice stone” sign was identified in 27 of 28 cases (96%). The most commonly affected sites of infection include the pelvic bones (38%; 13 of 34), vertebral bodies (32%; 11 of 34), and femurs (24%; 8 of 34). Adjacent soft tissue inflammation and emphysema was evident in 23 of 29 cases (79%). Cortical destruction, a key diagnostic feature of traditional osteomyelitis, was absent in 79% of cases of EO. We describe the “pumice stone sign” as a radiological sign to identify EO. We found it present in 96% of all currently known cases of EO. EO commonly involves the pelvic bones (38%), vertebral bodies (32%), and femur (24%). Key features also include adjacent soft tissue emphysema (79%) and absence of cortical destruction (79%).     

Osteomyelitis: detection with US

To evaluate the role of ultrasound (US) in the detection of osteomyelitis, the authors prospectively studied 48 patients clinically suspected of having osteomyelitis. A sonographic diagnosis was made if fluid was seen directly in contact with bone, without intervening soft tissues. Twelve of the 48 patients were subsequently found to have osteomyelitis. In 10 of them, US demonstrated abnormal fluid adjacent to the bone. This fluid was thought to represent an inflammatory exudate dissecting in a subperiosteal and/or extraperiosteal location. Eight of the 48 patients had soft-tissue fluid collections. The rest of the patients either had no abnormalities or had cellulitis. The authors conclude that US can be useful in the detection of osteomyelitis.     

Osteomyelitis in infants and children

Infection of the pediatric skeletal system is a dramatic diagnostic and therapeutic challenge. The consequences of a missed diagnosis could lead to long-lasting functional sequelae. This disease has multiple aspects according to the clinical presentation and evolution, the causative microorganism, the site of infection, and, finally, the patient's age and immunological status. The choice of the most appropriate imaging modality according to the clinical presentation is very important to assess the diagnosis, the extent of the disease, and to obtain the causative germ when needed; thus, plain films, ultrasound, nuclear medicine, computed tomography, and MR imaging are discussed, each of them having pros and cons. This multimodality approach of the musculoskeletal infections is mandatory to guide surgery, to deliver an appropriate antibiotic therapy, and to reduce the rate of long-term functional sequelae.     

Osteomyelitis, acute and chronic

In certain patient populations, osteomyelitis is a significant clinical problem. The judicious use of plain film radiographs and radionuclide bone imaging by the imaging consultant has a critical role in the early detection and diagnosis of osteomyelitis. This complementary imaging approach produces the highest and greatest accuracy in the documentation of skeletal infections. Inadvertent delay in the initiation of appropriate therapy can be obviated utilizing these imaging techniques and undue morbidity averted.     

Osteomyelitis in infants and children

Infection of the pediatric skeletal system is a dramatic diagnostic and therapeutic challenge. The consequences of a missed diagnosis could lead to long-lasting functional sequelae. This disease has multiple aspects according to the clinical presentation and evolution, the causative microorganism, the site of infection, and, finally, the patient's age and immunological status. The choice of the most appropriate imaging modality according to the clinical presentation is very important to assess the diagnosis, the extent of the disease, and to obtain the causative germ when needed; thus, plain films, ultrasound, nuclear medicine, computed tomography, and MR imaging are discussed, each of them having pros and cons. This multimodality approach of the musculoskeletal infections is mandatory to guide surgery, to deliver an appropriate antibiotic therapy, and to reduce the rate of long-term functional sequelae.     

Osteomyelitis: clinical update for practical guidelines

Bone infections represent a diagnostic or therapeutic challenge for the infectivologist, orthopaedic surgeon, radiologist and nuclear medicine physician. Staphylococcus aureus is the major bacterium responsible for bone infections although Mycobacterium tuberculosis is emerging as an infectious agent in Italy because of immigration from Africa and Asia. Osteomyelitis requires long and expensive antibiotic treatment, including rifampicin administered parenterally for several weeks and the use of antimicrobial-impregnated cement in prosthesis substitution. Sometimes it is necessary to carry out surgical debridement of a necrotic bone or the consolidation of compromised bones and joint prosthesis implants. Radiographs and bone cultures are mainstays for the diagnosis of bone infections but are often useless in the lengthy management of these patients. Diagnosis of skeletal infections still includes conventional radiography but magnetic resonance imaging is essential in haematogenous and spinal infections. Bone scans are still useful in acute osteomyelitis whereas scintigraphy using labelled white blood cells is preferred in infections of peripheral bone segments or joint prosthesis. In the axial skeleton a combination of an agent for detecting inflammation ((67)Ga citrate) and a metabolic agent ((99m)Tc-methylene diphosphonate) enables an infection and an area of increased metabolic activity to be distinguished. [(18)F]Fluorodeoxyglucose positron emission tomography, where available, has a significant impact in the study of infections using radionuclides: high-resolution tomographic images represent an effective alternative to gallium in the assessment of inflammation of spine lesions but a comparison with morphological examinations (computed tomography or magnetic resonance imaging) is essential.     

Osteomyelitis. A morphological and histological review

Summary Osteomyelitis is an infection of the bone marrow caused by both non-specific and specific agents. Non-specific endogenic osteomyelitis represents the most frequent form, followed by the specific form caused by Mycobacterium tuberculosis infection. Typically, the non-specific form occurs in children and young adults, and the sites most frequently affected are the distal and the proximal ends of the tibia and femur. In tuberculosis, osteomyelitis is predominantly located in the vertebral bodies. In rare cases osteomyelitis can be caused by viruses, fungi or echinococcus. It may also occur as so-called acute endogenic osteomyelitis, such as plasmocellular osteomyelitis and Brodie's abscess. Histologically, dense infiltration of leucocytes, granulation tissue and bone sequesters can be seen. In tuberculosis granulomas with central necrosis, epithelioid cells and giant cells of Langhans type are characteristically found. Most forms of acute osteomyelitis can be successfully treated with antibiotics, leading to complete healing without complications. Only a few reported cases develop into a secondary, chronic form. Eingegangen am 18. Juni 1996 Angenommen am 24. Juni 1996     

Osteomyelitis of the tarsal bones in children

The radiographic findings in seven children with tarsal osteomyelitis are described. The bones involved were the calcaneus, talus, cuboid, and navicular. The lesions appeared as single, subchondral, reasonably well-defined round lucencies measuring up to 12 mm in diameter. Bone scans were positive. The lesions healed slowly with surrounding sclerosis but no periosteal reaction.