Imaging characteristics and epidemiologic features of atypical mycobacterial infections involving the musculoskeletal system

Nontuberculous mycobacterial myositis in dermatomyositis with long-term use of immunosuppressant: a case report

Inflammatory myopathies, such as polymyositis and dermatomyositis, are systemic inflammatory disorders that affect skeletal muscles and internal organs. The treatment of inflammatory myopathies usually involves long-term use of high doses of steroids and/or immunosuppressants, making patients susceptible to opportunistic infections. Unfortunately, infections are a leading cause of morbidity and mortality in patients with inflammatory myopathies. Musculoskeletal nontuberculous mycobacterial infections are rare. Nontuberculous mycobacterial infections are easily overlooked owing to their rarity, leading to delayed diagnosis and treatment, indolent clinical course, and difficulty isolating the pathogen. Nontuberculous mycobacterial infections are a growing health concern because of their increasing incidence and the need for prolonged treatment. In patients with connective tissue diseases, immunosuppressant use may lead to an increased risk of nontuberculous mycobacterial infection with a poor prognosis, which highlights the need for early diagnosis and treatment. Herein, we report the case of a 59-year-old man diagnosed with dermatomyositis, who had prolonged use of immunosuppressants and developed a disseminated soft tissue infection in both thighs caused by Mycobacterium abscessus. Multimodal images were obtained using magnetic resonance imaging, ultrasonography, and computed tomography. A strong suspicion of possible combined opportunistic infections and appropriate staining is essential in diagnosing nontuberculous mycobacterial myositis.

Imaging findings of vertebral osteomyelitis caused by nontuberculous mycobacterial organisms: Three case reports and literature review

RATIONALE

Prompt diagnosis of nontuberculous Mycobacterial (NTM) vertebral osteomyelitis is challenging, yet necessary to prevent serious morbidity and mortality. Here, we report 3 cases of vertebral osteomyelitis caused by NTM with imaging findings.

PATIENT CONCERNS

Case 1, a 58-year-old male patient, was admitted to our hospital because of the presence of a pulmonary mass for 6 months with cough and chest pain.Case 2, a 50-year-old male patient, had fever and cough for 3 years and was diagnosed with tuberculosis. Antituberculosis treatment was ineffective, accompanied by lymph node enlargement and osteosclerotic changes involving vertebral bodies.Case 3, a 66-year-old female patient, was admitted to our hospital with a mass on the top of her head for 1 month, which ruptured in the last 2 weeks.

DIAGNOSES

Case 1: Sputum culture revealed Mycobacterium (M.) avium.Case 2: The final culture results of the lymph node biopsy samples were M. intracellulare.Case 3: Culture results of the sputum and pus from the abscess were M. gordon.We found sclerosing lesions in the spine in all 3 NTM patients, which were easily misdiagnosed as metastatic tumors. In 2 cases, there was bone destruction in the ilium with limbic sclerosis, and there were abscesses near the ilium and in front of the sacrum in 1 case.

INTERVENTIONS

Case 1 was transferred to other specialist hospital.Case 3 received surgical treatment for cranial lesions and abscess drainage.Case 2 and case 3 received targeted treatment for nontuberculous mycobacteria in our hospital.

OUTCOME

The condition of case 1 was unknown.Recovery of case 2 was uneventful because of prolonged illness; however, inflammation gradually improved overall.Case 3 had no recurrence following surgical treatment.

LESSONS

In our 3 cases of NTM vertebral osteomyelitis, bone lesions were often misdiagnosed as bony metastases because of the presence of multiple sclerotic lesions. Diagnoses were challenging and delayed. It is important to consider osteomyelitis by NTM when disseminated osteosclerosis with or without osteolytic bone lesions is present in conjunction with continuous inflammatory symptoms and signs. Moreover, an open biopsy of the lesion should be performed for a definitive diagnosis.

Lumbar Intervertebral Disc and Discovertebral Segment. Part 2: An Imaging Review of Pathologic Conditions With Anatomic Correlation

The lumbar intervertebral disc is a complex anatomic structure that can be affected by a number of distinct pathologic processes. Categories of the disease include degenerative changes, subclinical or overt trauma, infectious lesions, inflammatory insults, metabolic disease, and tumors. Abnormalities affecting the intervertebral disc may assume atypical appearances or alterations may as well mimic pathologic processes related to degeneration that can be asymptomatic. Although the imaging findings of degenerative diseases of the vertebral column have been emphasized extensively, the assembly of pathologic conditions associated with the discovertebral segment has not received adequate attention. This manuscript reviews and illustrates a range of abnormalities affecting the discovertebral segment, providing a detailed analysis of postmortem material, in the realm of a close anatomic-imaging correlation. Knowledge of the characteristic morphology and patterns of abnormal conditions affecting the intervertebral disc and discovertebral segment can help radiologists narrow the differential diagnosis in a broad spectrum of disease processes.

Non-tuberculous Mycobacterial Infection of the Musculoskeletal System Detected at Two Tertiary Medical Centres in Henan, China, 2016-2020

Non-tuberculous mycobacterial (NTM) infection of the musculoskeletal system is rare but poses a grave threat to public health. These infections yield non-specific symptoms that remain undetected until the development of the later stages of the disease. In this study, we performed a retrospective review of 25 cases of musculoskeletal NTM infection at two tertiary medical centres over a 5-year period to determine the clinical features and improve the current clinical diagnosis and treatment. The most common mycobacterial species detected were Mycobacterium fortuitum in eleven patients, Mycobacterium abscessus in eight patients, Mycobacterium houstonense in three patients, Mycobacterium avium in two patients, and Mycobacterium smegmatis in one patient. The sites of infection included the limbs and joints, most commonly the knee (ten patients) and foot (six patients). The median duration from the onset of symptoms to diagnosis was 2.5 months (0.8-13.5 months). Deep sinus tracts extending to the surgical site were observed in 60% of the patients (15/25), and granulomatous inflammation and granulomatous inflammation with necrosis occurred in 60% of the patients (15/25). All patients underwent surgical treatment for infection control, and all patients, except one, received antimycobacterial therapy based on drug sensitivity assays. The median duration of the antimicrobial chemotherapy was 5 months (range: 3-20 months). At the final follow-up, 24 patients presented with absence of recurrence and one patient succumbed owing to heart failure after debridement. Our findings highlight the importance of vigilance and improvements in the diagnostic methods for musculoskeletal NTM infection. Aggressive surgical treatment and antimycobacterial drug treatment can help achieve satisfactory results.

Vertebral osteomyelitis caused by Mycobacteroides abscessus subsp. abscessus resulting in spinal cord injury due to vertebral body fractures

Nontuberculous mycobacteria (NTM) rarely cause vertebral osteomyelitis; however, the clinical characteristics of vertebral osteomyelitis caused by NTM are poorly understood due to its rarity. A 74-year-old man with lung cancer was treated with prednisolone for immune checkpoint inhibitor-associated immune-related adverse events. He had been experiencing mild back pain without febrile episodes for five months, and was admitted to the hospital for worsening back pain and progressive paraplegia. Magnetic resonance imaging showed spinal cord compression at T4-5 due to fractures of the T5 and T7 vertebral bodies. The culture of a sample of pus from the T7 vertebral body obtained at the time of spinal fusion surgery yielded the Mycobacteroides abscessus (M. abscessus) complex. The patient was diagnosed with vertebral osteomyelitis caused by M. abscessus complex and treated with clarithromycin, amikacin, and imipenem; clarithromycin was later replaced by sitafloxacin because of inducible macrolide resistance. However, his neurologic deficits were irreversible, and he died due to a deteriorating general condition. The strain was identified up to subspecies level as M. abscessus subsp. abscessus by hsp65 and rpoB sequencing and nucleic acid chromatography. Although vertebral osteomyelitis due to NTM is rare, delayed diagnosis can lead to serious complications or poor outcomes. A prolonged clinical course, less frequent fever, vertebral destruction or spinal deformity, neurological deficits, or immunosuppressed conditions might be suggestive of NTM vertebral osteomyelitis.

Histoplasmosis tenosynovitis of the forearm and wrist: imaging, surgical and pathologic findings

Histoplasmosis is a disease endemic to several parts of the world, including South America. It progresses in a mostly asymptomatic and self-limiting manner but has the potential to cause disseminated pulmonary infection, especially in immunocompromised patients. Rare reports from the literature describe musculoskeletal manifestations related to the two varieties of the pathogen that cause histoplasmosis, namely, the capsulatum or duboissi variety. In this report, we describe the case of a previously healthy, middle-aged man, with slowly progressing pain in the right forearm, wrist, and fingers, diagnosed with a case of pathologically confirmed histoplasmosis tenosynovitis. We also describe the imaging, surgical, and histological findings and discuss the differential diagnoses for tenosynovitis, in case of atypical infections.

Giant Intraosseous Cyst-Like Lesions of the Metacarpal Bones in Rheumatoid Arthritis

The purpose of this study was to illustrate the clinical and imaging properties of giant intraosseous cyst-like lesions (GICLs) of the metacarpal bones extending beyond the central diaphysis in rheumatoid arthritis (RA) patients on magnetic resonance (MR) images. A keyword search was conducted to extract GICLs of the metacarpal bones out of MR reports in RA patients. There were nine GICLs extending from the subchondral bone region beyond the central diaphysis of the metacarpal bones on MR images in eight subjects with RA (seven females, one male). The age range was from 60 to 87 years with a median age of 65.5 years. The average disease duration was 13.1 years. As for the disease activity, one was low, six were moderate and one was high. None of the nine lesions were visible on radiography. The Steinbrocker stage distribution was as follows: I (n = 3), II (n = 2), and III (n = 3). Intraosseous cyst-like lesion of the metacarpal bones on MR images is a relatively rare manifestation in patients with long-standing RA. Although the lesion seems to be derived from subcortical bone break, it is not necessarily erosive in nature.

Approach to the diagnosis and treatment of non-tuberculous mycobacterial disease

Non-tuberculous mycobacteria (NTM) is a collective name given to a group of more than 190 species of Mycobacterium. The clinical presentation for most NTM infections is non-specific, often resulting in delayed diagnosis. Further complicating matters is that NTM organisms can be difficult to isolate. Medications used to treat NTM infection can be difficult for patients to tolerate, and prolonged courses of anti-mycobacterial therapy are often required for adequate suppression or eradication. Herein, we review different NTM syndromes, appropriate diagnostic tests, and treatment regimens.

Nontuberculous mycobacterial infection of the knee after arthrocentesis for idiopathic hemarthrosis: A case report

Introduction

Nontuberculous mycobacterial (NTM) infections of the musculoskeletal system are uncommon. Such infections are typically acquired by direct inoculation after penetrating trauma, surgical procedures, or needle injections. There are no reported cases of NTM infection after arthrocentesis for idiopathic hemarthrosis of the knee. Here we report a case of NTM infection in the knee that developed after arthrocentesis for idiopathic hemarthrosis of the knee.

Presentation of case

The patient was an 85-year-old woman who experienced swelling of the left knee. An arthrocentesis was carried out, and hemarthrosis was found. The patient was referred to our hospital for repeated recurrence of hematoma of the knee. Significant swelling was observed in the suprapatellar sac. Magnetic resonance imaging examination revealed a mass at the suprapatellar sac. Laboratory data showed elevation of inflammatory markers. Debridement was performed under arthroscopy and samples were collected for culture. Although routine microbiological cultures were negative, the patient continued to experience knee swelling and laboratory data showed high C-reactive protein levels. Therefore, open debridement was carried out. At 4 weeks after the first surgical treatment, intraoperative cultures yielded Mycobacterium intracellulare. At this point, we diagnosed septic arthritis of the knee due to NTM infection. The patient showed an excellent prognosis with three-drug medical treatment for 1 year.

Conclusion

Clinically, diagnosis of septic arthritis due to NTM infection is not easy. Because selection of examination depends on clinical suspicion, NTM infections should be considered for patients with elevation of inflammatory markers after episodes of surgical procedures, and/or needle injections.

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・Nontuberculous mycobacterial (NTM) infections of the musculoskeletal system are uncommon.

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・A case of NTM infection in the knee that developed after arthrocentesis.

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・NTM infections should be considered for patients with elevation of inflammatory markers after needle injections.

Recurrent Nontuberculous Mycobacterial Tenosynovitis

Background: Nontuberculous mycobacteria are an uncommon pathogen for musculoskeletal infection and are difficult to treat because of delays in diagnosis, prolonged treatment requiring both antimycobacterial therapy and surgical debridement, and high rates of resistance to antimycobacterial therapy.

Case Report: We report the case of an 88-year-old male with recurrent Mycobacterium avium complex tenosynovitis despite receiving multiple courses of pharmacologic therapy and surgical debridement.

Conclusion: Nontuberculous mycobacterial musculoskeletal infections can be difficult to diagnose and equally difficult to treat. A combination of antimycobacterial therapy and surgical debridement is often required; however, the rate of treatment failure remains high, particularly with rapidly growing mycobacteria such as Mycobacterium avium.

Infectious Rice Body Formation in a Patient with Anti-aminoacyl-t RNA Synthetase Syndrome: A Case Report

CASE

An adult woman with anti-aminoacyl-t RNA synthetase syndrome developed pain and swelling of both hands and her left forearm, initially diagnosed as seronegative rheumatoid arthritis. Surgical exploration revealed multiple "rice bodies," and the specimen grew Mycobacterium intracellurale. She subsequently received antibiotic therapy.

CONCLUSION

In the diagnosis of rice body formation in musculoskeletal tissues, it is necessary to consider not only rheumatic diseases but also mycobacterial infection.

Osteomyelitis and septic arthritis after Mycobacterium Bovis BCG Therapy for Urinary Bladder Cancer

Mycobacterium bovis (M. bovis) Bacillus Calmette-Guerin (BCG) - an attenuated strain of M. bovis - is closely related to Mycobacterium tuberculosis and may be used as a vaccine against tuberculosis as well as a treatment for urinary bladder cancer. Complications of M. bovis BCG administration, while rare, can occur. While a few cases of vertebral osteomyelitis secondary to BCG therapy exist in the literature, and while there are case reports of osteomyelitis and septic arthritis from BCG vaccination (Chen et al., 2017; Huang et al., 2019; Lin et al., 2015 [1-3]), there are no reported cases of osteomyelitis and septic arthritis involving the foot from BCG therapy for urinary bladder cancer. We present an unusual presentation of osteomyelitis and septic arthritis of the tarsometatarsal joints after M. bovis BCG therapy for urinary bladder cancer. We will describe MRI and ultrasound findings in our case of M. bovis BCG osteomyelitis and septic arthritis.

Mycobacterial Infections in the Hand and Wrist

Mycobacterial hand infections are uncommon. These infections have an indolent course and are marked by variable and nonspecific presentations, often leading to diagnostic and treatment delays. The pathogens involved in mycobacterial hand infections include Mycobacterium tuberculosis complex, atypical mycobacteria, and M leprae. Initial treatment involves a combination of long-term antibiotics and surgical débridement to cure the infection. Reconstructive procedures aid in restoring hand function lost secondary to the disease.

Abnormal Conditions of the Diskovertebral Segment: MRI With Anatomic-Pathologic Correlation

OBJECTIVE. The purpose of this article is to review the appearance of various abnormalities that affect the lumbar intervertebral disk and diskovertebral segment through anatomic-pathologic correlation in cadavers. CONCLUSION. Familiarity with the pathologic conditions in and around the intervertebral disk is important in recognizing such conditions as a potential source of symptoms. We revisit the principal role of MRI in evaluating these abnormalities and excluding other sources of significant clinical manifestations.

Nontuberculous mycobacterial infections of the lower extremities: A 15-year experience

Objectives

Nontuberculous mycobacterial infection (NTMI), which is increasing in prevalence, is challenging to diagnose and manage despite the availability of capable laboratories because of subtle and nonspecific clinical findings and nonstandardized treatment guidelines. We aimed to present our experience with lower-extremity NTMI and to compare clinical characteristics and treatment outcomes between immunocompetent and immunocompromised patients.

Methods

To determine clinical presentations and outcomes, we reviewed electronic health records of all patients with lower-extremity NTMI treated and followed up at our institution from January 2002 through December 2017.

Results

Twenty-four patients were included in this study. Mean (SD) age was 58 (19) years. Eighteen patients (75%) were men; 13 (54%) were immunocompetent; and 9 (37%) had bone and joint involvement. No significant differences existed between immunocompetent and immunocompromised patients, except immunocompetent patients had significantly more infections at the hip, thigh, and toe. Bone and joint infection required significantly longer treatment time than skin and soft-tissue infection.

Conclusions

Regardless of immune status, patients with lower-extremity NTMI had similar characteristics, treatments, and outcomes. However, immunosuppression can be a major risk factor in the development of disseminated NTMI and associated complications. Acid-fast bacilli culture is strongly recommended for evaluation of delayed or nonhealing lesions. Aggressive medical and surgical management can be associated with good clinical outcomes.

Nontuberculous mycobacterial infection of the musculoskeletal system in immunocompetent hosts

BACKGROUND

Nontuberculous mycobacteria (NTM) were considered saprophytic organisms for many years but now are recognized as human pathogens. Although humans are routinely exposed to NTM, the rate of clinical infection is low. Such infections usually occur in the elderly and in patients who are immunocompromised. However, there has been an increasing incidence in recent years of infections in immunocompetent hosts. NTM infections in immunocompetent individuals are secondary to direct inoculation either contamination from surgical procedures or penetrating injuries rather than hematogenous dissemination. Clinically and on histopathology, musculoskeletal infections caused by NTM resemble those caused by Mycobacterium tuberculosis but are mostly resistant to routine antituberculosis medicines.

MATERIALS AND METHODS

Six cases of NTM infection in immunocompetent hosts presenting to the department from 2004 to 2015 were included in study. Of which two cases (one patella and one humerus) of infection were following an open wound due to trauma while two cases (one hip and one shoulder) of infection were by inoculation following an intraarticular injection for arthrogram of the joint, one case was infection following arthroscopy of knee joint and one case (calcaneum) was infection following local injection for the treatment of plantar fasciitis. All patients underwent inaging and tissue diagnosis with samples being sent for culture, staining, and histopathology.

RESULTS

Clinical suspicion of NTM inoculation led to the correct diagnosis (four cases with culture positive and two cases with histopathological diagnosis). There treatment protocol for extrapulmonary NTM infection was radical surgical debridement and medical management based on drug sensitivity testing in culture positive cases. At a mean follow up of 3 years (range1-9 years) all patients had total remission and excellent results.

CONCLUSIONS

Whenever a case of chronic granulomatous infection is encountered that does not respond to standard anti-tuberculous treatment, with a history of open trauma, surgical intervention, or injection as shown in this study, a possible NTM infection should be considered and managed appropriately.

Shoulder Pain after Fall, Septic Shock, and Pyomyositis Associated with Breast Cancer Chemotherapy and Lymphedema

Background

As a symptom of pyomyositis, sepsis usually follows local inflammation signs. Here, we report pyomyositis with lymphedema of upper extremity in which septic shock and poor local findings initially presented during chemotherapy for breast cancer.

Case Report

An 80-year-old woman presented with chronic right shoulder pain during chemotherapy for the recurrent disease. She had a history of postmastectomy lymphedema, diabetes mellitus, and repeated hyaluronic acid injections to the shoulder joint. The pain suddenly worsened with septic shock and no apparent local signs. Magnetic resonance imaging revealed myonecrosis, and no pus was yielded by ultrasound-guided needle aspiration. After 2 weeks of recovery by conservative medical management, surgical drainage was performed. Late formulated massive intramuscular pus showed severe neutrophil infiltration and myonecrosis.

Conclusion

Pyomyositis can develop into septic shock with poor local signs. Myelosuppression after chemotherapy can cause myonecrosis without macroabscess, and magnetic resonance imaging was useful for the diagnosis of this condition. When unspecified local pain appears during cancer chemotherapy we should consider this disease, too.

Mycobacterium kansasii causing chronic monoarticular synovitis in a patient with HIV/AIDS

Mycobacterium kansasii is a nontuberculous mycobacterium that primarily causes pulmonary disease in AIDS patients, however it has also been known, rarely, to result in skeletal infection. When skeletal infection occurs, the time from onset of symptoms to diagnosis is up to 5 years in previously reported cases. We describe a 48-year-old woman with HIV/AIDS who presented with chronic, isolated left knee pain and swelling of over two decades which had recently worsened. Radiographs and magnetic resonance imaging demonstrated marked subarticular erosions, synovial thickening, and bone marrow edema, which had progressed compared with prior imaging done seven years earlier. Synovial biopsy grew Mycobacterium kansasii. Following the presentation of our case, clinical and imaging findings, including the differential diagnosis, of monoarticular arthritis caused by Mycobacterium kansasii are reviewed and discussed.

A 14-year-old girl with thoracolumbar pain

We report the second case of Mycobacterium kansasii spondylitis in a 14-year-old Caucasian girl who presented with pain in the thoracolumbar region. There was collapsed T8 and discitis, and a cavitary lesion in new chest CT. Biopsy taken from thoracic lesion T8 with CT guidance which had evidence of osteomyelitis and its smear were negative for acid fast bacilli. Bronchoalveolar lavage (BAL) was performed - PCR was negative for acid fast bacilli. Empirical treatment of tuberculosis started and her symptoms resolved. PCR of thoracic sampling revealed M. kansasii after one month. Two months after treatment of M. kansasii, her thoracolumbar pain resolved and the cavitary lesion of the lung disappeared. In patients who are immunocompromised in the association of cavitary pulmonary lesion and infectious spondylitis, atypical mycobacteria may be on the list of common clinical diagnoses but not in immunocompetent patients such as our patient.

Common and unusual urogenital Crohn's disease complications: spectrum of cross-sectional imaging findings

Involvement of the urinary tract and genital organs is not uncommon in patients affected with Crohn's disease (CD). Occurring in both sexes, uro-gynecological complications are often clinically unsuspected because of the dominant intestinal or systemic symptoms. Knowledge of their manifestations and cross-sectional imaging appearances is necessary to recognize and report them, since correct medical or surgical treatment choice with appropriate specialist consultation allows to prevent further complications. Besides uncomplicated urinary tract infections that usually do not require imaging, urolithiasis and pyelonephritis represent the most commonly encountered urinary disorders: although very useful, use of computed tomography (CT) should be avoided whenever possible, to limit lifetime radiation exposure. Hydronephrosis due to ureteral inflammatory entrapment and enterovesical fistulization may result from penetrating CD, and require precise imaging assessment with contrast-enhanced CT to ensure correct surgical planning. Representing the majority of genital complication, ano- and rectovaginal fistulas and abscesses frequently complicate perianal inflammatory CD and are comprehensively investigated with high-resolution perianal MRI acquired with phased-array coils, high-resolution T2-weighted sequences and intravenous contrast. Finally, rare gynecological manifestations including internal genital fistulas, vulvar and male genital involvement are discussed.

Extrapulmonary infections associated with nontuberculous mycobacteria in immunocompetent persons

Over the past several years, the prevalence of human disease caused by nontuberculous mycobacteria (NTM) has increased. Whether the increase in cases is real or whether more cases are being recognized remains unclear. Despite a considerable increase in knowledge about NTM infections, they still represent a diagnostic and therapeutic challenge for several reasons: 1) pathogenic isolates may be indistinguishable from contaminant or saprophytic isolates; 2) timely and reliable identification of isolates may depend on proper communication between clinicians and laboratory staff; 3) lack of standardized susceptibility testing makes adoption of tailored therapies unrealistic; and 4) lack of treatment guidelines exposes patients to toxic drugs and disappointing outcomes. Laboratory research and multicenter controlled trials are needed to improve diagnosis and treatment of these infections.

Spinal infection caused by Mycobacterium avium complex in a patient with no acquired immune deficiency syndrome: a case report

Spinal infection caused by Mycobacterium avium complex (MAC) is rarely seen in people who do not have acquired immune deficiency syndrome. We report such a case in a 60-year-old man who underwent anterior spinal fusion after treatment with antibiotics had failed. The presentation of MAC spinal infection is different from that seen in MAC lung infection, with more than half presenting with urgent or semi-urgent neurological deficits. Younger patients who are not immunocompromised can also be infected. It should be considered as a differential diagnosis in patients with tuberculosis of the spine. The use of antibiotics should be based on the cultured organism's sensitivity results. Indications for surgery are progressive bony destruction, abscess formation, and neurological compression.

[MRI of knee tuberculous arthritis]

Tuberculous arthritis is rare and the diagnosis may be confused with inflammatory arthritis. Only few cases, explored by MRI, have been reported in the literature. We report 3 cases of tuberculous arthritis of the knee revealed by insidious pain. The abnormalities revealed by MRI suggested tuberculosis. Diagnosis was confirmed by histology.

MR imaging findings of pyogenic bacterial myositis (pyomyositis) in patients with local muscle trauma: illustrative cases

Pyogenic myositis (pyomyositis) represents a bacterial infection of muscle, usually caused by Staphylococcus aureus that is endemic in tropical regions. Pyomyositis commonly affects patients who are immunocompromised or who have underlying chronic disorders. Lower extremity localization of infection is typical. The most common pattern of disease, however, appears to be a solitary abscess in the quadriceps musculature. Delay in accurate diagnosis is frequent and clinical deterioration can be precipitous. In view of the high associated morbidity, early imaging to detect, localize, and define disease extent is important. Magnetic resonance imaging (MRI) plays a key role in the definitive diagnosis of pyomyositis. This article provides a pictorial illustration of the spectrum of MRI findings associated with pyogenic myositis.

Imaging of osteomyelitis: current concepts

Osteomyelitis frequently requires more than one imaging technique for an accurate diagnosis. Conventional radiography still remains the first imaging modality. MRI and nuclear medicine are the most sensitive and specific methods for the detection of osteomyelitis. MRI provides more accurate information regarding the extent of the infectious process. Ultrasound represents a noninvasive method to evaluate the involved soft tissues and cortical bone and may provide guidance for diagnostic or therapeutic aspiration, drainage, or tissue biopsy. CT scan can be a useful method to detect early osseous erosion and to document the presence of sequestra. PET and SPECT are highly accurate techniques for the evaluation of chronic osteomyelitis, allowing differentiation from soft tissue infection.

Rice-body formation in atypical mycobacterial tenosynovitis and bursitis: findings on sonography and MR imaging

OBJECTIVE

This article describes rice bodies found in patients with atypical mycobacterial tenosynovitis and bursitis, emphasizing the sonographic and MR imaging appearances of these small bodies.

CONCLUSION

Rice bodies occur in patients with atypical mycobacterial tenosynovitis and bursitis. When small, rice bodies are better visualized on MR imaging than on sonography, allowing the radiologist to consider appropriate diagnoses.

Imaging in dialysis spondyloarthropathy

Destructive spondyloarthropathy has recently been described in patients who undergo maintenance hemodialysis for chronic renal disease. The condition most frequently involves the lower segment of the cervical spine, although the craniocervical junction also may be affected. Although the pathogenesis of destructive spondyloarthropathy remains unclear, the disorder is thought to relate to a hemodialysis-associated amyloidosis. It appears that the disease correlates with the duration of hemodialysis, although it has been reported in patients with chronic renal insufficiency not associated with hemodialysis. Radiographic features simulate those of an infectious process, encompassing a range of abnormalities from superficial erosions to large bony defects. Computed tomography (CT) images reveal osteolytic areas, with bone sclerosis of adjacent vertebral endplates, and minimal osteophytosis. The intervertebral spaces appear narrow or obliterated. On magnetic resonance imaging (MRI), the disorder may show the imaging characteristics of spondylodiskitis. The absence of high signal intensity on T2-weighted images generally helps to eliminate the diagnosis of an infection. With progression of the disease, collapse of a vertebral body and spinal instability may occur. Severe complications of destructive spondyloarthropathy in long-term dialysis patients may include spinal cord compromise, necessitating surgical decompression, with or without spinal stabilization.