Intramuscular Abscess Research Articles

Disseminated tuberculosis complicated by intramuscular abscesses, meningoencephalitis, and hemophagocytic lymphohistiocytosis: a case report

BackgroundAs disseminated extrapulmonary tuberculosis infection can involve multiple systems and result in atypical clinical manifestations that mimic other diseases, the diagnosis may be difficult, especially in elderly patients. Delaying treatment can adversely affect the prognosis. And to achieve better prognosis, early detection and diagnosis are necessary, as well as early initiation of comprehensive treatment.Case presentationWe present the case of a 78-year-old man with disseminated tuberculosis who developed the uncommon complication of urinary retention due to a psoas abscess, meningoencephalitis, and the rare secondary hemophagocytic lymphohistiocytosis syndrome. The patient achieved a favorable outcome following targeted therapy with antitubercular medications.ConclusionsThis case highlights that disseminated extrapulmonary tuberculosis infection can present with a variety of manifestations, and may exhibit many rare and complex clinical presentations. Prompt and accurate diagnosis and treatment play a crucial role in improving prognosis for the patients with persistent fever.

Multiple Intramuscular Abscesses Caused by <i>Nocardia abscessus</i> in a Patient with Chronic Obstructive Lung Disease: Clinical Microbiology Considerations

Nocardiosis is uncommon. Immunocompromising conditions predispose individuals to pulmonary and disseminated nocardiosis of the brain, skin, and subcutaneous tissues. The most common pathogens are <i>Nocardia cyriacigeorgica</i>, <i>Nocardia nova</i>, and <i>Nocardia farcinica</i>. The speciation of <i>Nocardia</i> to determine antimicrobial susceptibility is difficult using traditional biochemical methods. Here, we report the case of a 73-year-old man with chronic obstructive lung disease who developed a rapidly progressing intramuscular abscess around the left hip and thigh. Within 3 days, the lesions progressed to an epidural abscess at the L4 to S1 level. Although he was treated with broad-spectrum antibiotics and extensive incision and drainage, he died of rapidly progressive respiratory failure. <i>Nocardia abscessus</i> (<i>N. abscessus</i>) was identified in pus samples using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). This case shows that the diagnosis of an intramuscular abscess caused by <i>N. abscessus</i> is challenging and that using MALDI-TOF MS may facilitate the diagnosis and ensure appropriate treatment.

Recurrent bicycle falls by an elderly man who developed multiple intramuscular abscesses associated with urine leakage secondary to posterior urethral injury caused by pelvic ring disruption

Key Clinical MessageWith the aging of the population, physicians need to pay more attention to assessing the presence or absence of pelvic fractures and urinary retention associated with urethral injury due to such fractures in the elderly when falling from bicycles.AbstractWalking ability does not rule out the presence of pelvic fractures. Many geriatric patients are likely to fall off bicycles. Physicians should pay more attention when assessing complications related to urethral trauma caused by pelvic fractures in the elderly after falling from bicycles.

Subscapular abscesses: A literature review and evidence-based treatment guidelines.

An intramuscular abscess of the subscapularis is a rare phenomenon but important pathology for surgeons to be aware of because clinical deterioration can be rapid and diagnosis difficult. The presentation often mimics other common shoulder pathologies with subacute shoulder pain and stiffness. Early diagnosis, antibiotics and surgical drainage are critical to reduce the spread and joint destruction. A search of PubMed and Google Scholar databases identified cases of subscapular intramuscular abscess. Data collected about each case included patient demographics, presentation, pathology, surgical treatment and outcome. The authors report one additional subscapular abscess case. Data from 17 cases of subscapular abscess were found, 16 in the literature and one case described by the authors. Sixteen of 17 cases (94.1%) presented with shoulder pain and reduced range of motion worsening over a mean of 6.7 days prior to presentation. Surgical approaches utilised included a posterior inferomedial approach, deltoid-pectoral approach and one posterior inferolateral approach. From the limited data available regarding subscapular intramuscular abscess, the authors make the following recommendations: (1) Empirical antibiotics covering Staphylococcus aureus +/- methicillin-resistant Staphylococcus aureus, (2) drainage is indicated in all cases; and (3) tendon-sparing approaches can access an abscess in most locations within the subscapular space.

Imaging case series of melioidosis: the great masquerader

BackgroundMelioidosis is an infectious disease caused by Gram-negative bacterium Burkholderia pseudomallei. It is endemic to Southeast Asia. Inhalation, inoculation and ingestion are major routes of transmission. Increased risk of infection is seen in patients with diabetes, alcoholism, chronic renal and liver failure and malignancy. The aim of the present case series is to describe the varied imaging manifestations of melioidosis.Case presentationThis is a retrospective review of imaging findings in eight patients with culture-proven B. pseudomallei infections diagnosed in our institute from September 2019 to September 2021. A total of eight culture-proven melioidosis cases were reported from our institute. All of them had multiorgan involvement and predisposing conditions or risk factors, most common being diabetes mellitus and alcoholism. Lung was the most common organ involved showing nodules and consolidations followed by liver and spleen demonstrating multiple ‘honeycomb’-like abscesses. Musculoskeletal manifestations included osteomyelitis and intramuscular abscess. Cerebral abscess, cerebral infarcts, prostatic abscess, abdominal aortic mycotic aneurysm with periaortic hematoma and splenic vein thrombosis with splenic infarcts were a few other manifestations.ConclusionsMelioidosis is a great mimicker with acute, subacute or chronic clinical course involving multiple organs and resembling other common infections. Hence, it should be considered as a possible etiological agent when evaluating patients with risk factors and multiorgan involvement.

Beyond the abdominal and pelvic cavity: abdominal wall and spinal "Aunt Minnies".

Abdominal wall and spinal soft tissue findings are frequently encountered on CT or MR imaging of the abdomen and pelvis. Many of these entities have specific imaging findings, for which a definitive diagnosis can be made without the need for further work up. These abdominal wall and spinal findings may be diagnostically challenging for sub-specialized abdominal radiologists who are unfamiliar with their appearance and appropriate management. This review article describes and illustrates pathognomonic or characteristic abdominal wall and spinal pathologies, which reside outside the abdominopelvic cavity. The cases selected all have findings that allow a confident diagnosis without further imaging or intervention. The cases presented include myonecrosis, intramuscular abscess, myositis, iliopsoas bursitis, Morel-Lavallée lesion, hydrocele of canal of Nuck, Klippel Trenaunay Weber syndrome, neurofibroma with target sign, perineural cysts, filum terminale lipoma, calvarial bone flap, transverse rectus abdominis muscle (TRAM) flap, liposuction, and hidradenitis suppurativa, among others. Although not all-encompassing, this paper will help abdominal radiologists to accurately diagnose a variety of abdominal and pelvic extra-cavitary soft tissue pathologies by identifying key radiologic findings.

A rare case of melioidosis presenting as myositis in Sri Lanka

BackgroundMelioidosis caused by Burkholderia pseudomallei is an emerging infection in Sri Lanka with a high case fatality rate. The disease usually manifests as pneumonia, however multisystem involvement is common. Myositis is an extremely rare occurrence and this is the only documented case where the initial presentation of melioidosis has been myositis and later complicated to myonecrosis.Case presentationA 45-year-old gentleman with pre-existing diabetes presented with a tender, right thigh lump for 1 week duration without any history of trauma or infection. Investigations revealed neutrophil leukocytosis, high erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels whilst ultrasonography showed focal myositis of right quadriceps. The patient went into sepsis amidst antibacterial treatment which warranted urgent surgery. At surgery, a large intramuscular abscess with myonecrosis was observed within vastus medialis which was completely drained and pus was taken for culture which eventually isolated Burkholderia pseudomallei. Melioidosis was diagnosed and intravenous meropenem was prescribed for 3 weeks. Following complete recovery, the patient was discharged on doxycycline and trimethoprim sulfamethoxazole for 3 months.ConclusionsMelioidosis, an endemic disease in south east Asia and northern Australia, is an emerging infection in Sri Lanka. Myositis is a rare presentation of the disease that can lead to myonecrosis and abscess formation which can cause rapid disease escalation and sepsis. Early surgical intervention may be life-saving in such cases where antibiotic therapy alone may not suffice.

Intramuscular abscess following routine newborn immunization: A case report

Intramuscular abscess following routine newborn immunization: A case report

Intramuscular abscess following routine newborn immunization: A case report

Intramuscular abscess following routine newborn immunization: A case report

Invasive Burkholderia cepacia Complex Infections among Persons Who Inject Drugs, Hong Kong, China, 2016-2019.

During March 2016–January 2019, Burkholderia cepacia complex (BCC) infection developed in 13 persons who inject drugs (PWID) in Kowloon West Region, Hong Kong, China. Seven cases were infective spondylitis, 2 endocarditis, 2 septic arthritis, 1 intramuscular abscess and bacteremia, and 1 necrotizing fasciitis. Pulsed-field gel electrophoresis revealed that the isolates from 9 patients were clonally related. This clone caused major illness, and 11 of the 13 patients required surgical treatment. Clinicians should be aware of this pathogen and the appropriate broad-spectrum antimicrobial drugs to empirically prescribe for PWID with this life-threatening infection. Close collaboration among public health authorities, outreach social workers, and methadone clinics is essential for timely prevention and control of outbreaks in the PWID population.

Diagnosis of toothpick-induced chronic intramuscular abscess using fistulography in a dog

Diagnosis of toothpick-induced chronic intramuscular abscess using fistulography in a dog

Photo Quiz: HIV-Infected Female with Thigh Pain.

A 50-year-old female who was recently diagnosed with HIV was admitted to the emergency department with a 4-week history of cough, weight loss, anorexia, pain, erythema, and an edema on the right lateral thigh. The patient reported an increase in pain and the size of this swelling as well as restrictions to normal movement of the right leg within 1 week of being admitted to our hospital. There was no preceding history of trauma. Six months before admission to the hospital, her CD4+ cell count was 22 cells/mm3, and her HIV RNA level was 104,222 copies/ml. On physical examination, the patient was malnourished, afebrile, had a blood pressure of 110/80 mm Hg, pulse of 93 beats per minute (bpm), respiratory rate of 24 breaths/min, an oxygen saturation of 95% on room air, and her HIV was controlled. Laboratory studies showed the following: nonreactive Mantoux test; hemoglobin, 8.7 g/dl (reference value, 13.0 to 18.0 g/dl); platelet count, 343 × 109/liter (reference value, 140 to 450 × 109/liter); leukocyte count, 9.9 × 109/liter (reference value, 4 to 11 × 109/liter); and normal liver and renal functions. A chest X-ray revealed bilateral micronodular infiltrate (Fig. 1A), and the ultrasound scan revealed an intramuscular abscess in the lateral part of her right thigh. An X-ray did not reveal osteomyelitis. The patient was treated with cephalexin at 500 mg every 6 h (q6h) for 7 days; however, pus was accumulated, and the abscess was drained (Fig. 1B). Microbes were detected by acid-fast staining of primary clinical material (Fig. 1C) and culture growth (Fig. 1D).

Infectious Myositis

Infectious myositis (IM), is the infection of the skeletal muscle tissue (particularly voluntary muscle), which is characterized by swelling, pain, tenderness and/or weakness and is most commonly caused by bacteria, frequently by Staphylococcal and Streptococcal species. Acute bacterial myositis is the diffuse infection of the muscle without an intramuscular abscess. Group A Streptococcus (GAS), is the most common cause of cellulitis and various muscular infections like pyomyositis, subacute myositis, acute myositis and malignant myositis. Viral agents are the most common cause of nonbacterial infectious myositis. Among viruses, influenza is the most frequent causative agent reported to cause viral myositis. Fungal infections of the musculature are relatively uncommon; most of the cases are seen in immunocompromised patients and the diagnosis is established through biopsy with the culture of the specimens. History of food ingestion along with eosinophilia points towards a parasitic causative agent.

Unusual Case of Pelvic Osteomyelitis Revealing Osteoporosis

Pelvic osteomyelitis is an uncommon and challenging condition to treat. Pressure ulcers, spinal injuries, contiguous sources of tracking infections, pelvic surgical procedures, traumatic injuries and open fractures all serve as nidi for developing pelvic osteomyelitis. We present a case of pelvic osteomyelitis suspected to be caused by insufficiency fractures due to osteoporosis in an anorexic adult.51 year old postmenopausal Caucasian female with undiagnosed anorexia presented to the hospital for severe right-sided pelvic pain and nausea. She denied fevers, vomiting, trauma, surgical procedures, history of pelvic infections, abnormal vaginal discharge, travel, prolonged steroid therapy. She disclosed a strict vegetarian diet, excessive daily exercise, low dairy intake and over 100lb intentional weight loss over the past 30 years. She reported normal menses, used oral contraceptives between ages of 25 to 30, and reached menopause at 49 years. For many years, she denied medical care including age-appropriate cancer screenings. She is employed in academia and denies tobacco, alcohol or drug use. On admission, height 153cm and weight 43kg, BMI 16.7kg/m2. Examination was notable for frail body habitus, moderate RLQ and pelvic tenderness, prominent PSIS and SI joints with decreased RLE range of motion. Laboratory results showed calcium 9.5mg/dL (n 8.6–10.4), phosphorus 4.1mg/dL (2.5–4.5), ALP 181IU/L (45–115), PTH 23pg/dL (n 9–76), Vitamin D 35ng/dL (n 25–80), 24-hour urinary calcium 285mg/24h (n 50–400). Abdominopelvic CT scan showed chronic right pubic ramus and bilateral sacral insufficiency fractures confirmed on MRI with septic arthritis of the pubic symphysis, osteomyelitis of pubic bodies and intramuscular abscess extending to the right adductor muscle. Wound culture was positive for Streptococcus viridans and pelvic bone biopsy showed degenerative changes. The patient completed IV Ceftriaxone therapy and underwent DXA scan confirming osteoporosis (T-scores:-3.8 lumbar spine L1-L4, -3.6 left femoral neck, -3.3 right femoral neck). Alendronate 10mg daily and calcium citrate-vitamin D 1000mg-800IU twice daily was prescribed. Diagnostic workup for secondary causes of severe osteoporosis was unremarkable except for hypercalciuria, for which calcium supplement was held with a plan to repeat in the future. Concern for her cachectic appearance and severity of her illness also elicited a dietician referral. Pelvic osteomyelitis and septic arthritis are seldom found without inciting insults. We report an atypical cause of presumed anorexia induced osteoporosis resulting in pelvic osteomyelitis. Untreated osteoporosis may lead to fracture, resulting in inflammation and predisposing patients to infections. Thus, early recognition and evaluation of osteoporosis in patients at high risk for fracture, such as patients with anorexia, is critical for prevention.

Man With Cat Bite

A previously healthy 21-year-old man presented to the emergency department with worsening left thigh pain during 2 months. Physical examination result was significant for tenderness in the region of small puncture wounds to the left upper thigh (Figure 1). He reported he was bitten by a cat 2 months before. Knee and thigh examination results were otherwise unremarkable. Point-of-care ultrasonography demonstrated a septate hypoechoic mass (Figure 2). Contrast-enhanced computed tomographic (CT) scan revealed a multiloculated, intramuscular abscess with extension into the knee capsule, suggestive of septic arthritis (Figure 3).Figure 2Hypoechoic, septate mass in the longitudinal view on bedside ultrasonography (arrow).View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 3Contrast-enhanced CT demonstrating a multiloculated, soft tissue abscess extending into the knee joint space, suggestive for septic arthritis (arrows).View Large Image Figure ViewerDownload Hi-res image Download (PPT) Pyomyositis with pyogenic arthritis. Pyomyositis is a collection of purulent material in the skeletal muscle, commonly occurring in the setting of systemic immunodeficiency, intravenous drug abuse, concurrent infection, or trauma. Although the majority of cases are due to Staphylococcus aureus, our patient’s traumatic inoculation was determined to be from oral cat flora. Patients typically present with pain localized to the involved muscle, with progression to significant tenderness, marked edema, and fever.1Crum N.F. Bacterial pyomyositis in the United States.Am J Med. 2004; 117: 420-428Abstract Full Text Full Text PDF PubMed Scopus (205) Google Scholar If pyomyositis is left untreated, systemic toxicity can result. In addition, pyogenic arthritis classically presents with an edematous, erythematous, and markedly tender joint with decreased range of motion. The patient presented with normal vital signs, appeared nontoxic, and demonstrated full range of motion of the affected thigh and knee. The sensitivity of point-of-care ultrasonography for soft tissue infection is approximately 96%, with a specificity of 83%.2Barbic D. Chenkin J. Cho D.D. et al.In patients presenting to the emergency department with skin and soft tissue infections what is the diagnostic accuracy of point-of-care ultrasonography for the diagnosis of abscess compared to the current standard of care? a systematic review and meta-analysis.BMJ Open. 2017; 7e013688PubMed Google Scholar,3Gottlieb M. Avila J. Chottiner M. et al.Point-of-care ultrasonography for the diagnosis of skin and soft tissue abscesses: a systematic review and meta-analysis.Ann Emerg Med. 2020; 76: 67-77Abstract Full Text Full Text PDF PubMed Scopus (14) Google Scholar Evaluating for underlying soft tissue abscesses can be difficult and using bedside ultrasonography can aid in guiding further evaluation. Our patient underwent surgical drainage with arthrocentesis and was successfully discharged after a prolonged course of intravenous antibiotics.

Treating Porcine Abscesses with Histotripsy: A Pilot Study

Infected abscesses are walled-off collections of pus and bacteria. They are a common sequela of complications in the setting of surgery, trauma, systemic infections and other disease states. Current treatment is typically limited to antibiotics with long-term catheter drainage, or surgical washout when inaccessible to percutaneous drainage or unresponsive to initial care efforts. Antibiotic resistance is also a growing concern. Although bacteria can develop drug resistance, they remain susceptible to thermal and mechanical damage. In particular, short pulses of focused ultrasound (i.e., histotripsy) generate mechanical damage through localized cavitation, representing a potential new paradigm for treating abscesses non-invasively, without the need for long-term catheterization and antibiotics. In this pilot study, boiling and cavitation histotripsy treatments were applied to subcutaneous and intramuscular abscesses developed in a novel porcine model. Ultrasound imaging was used to evaluate abscess maturity for treatment monitoring and assessment of post-treatment outcomes. Disinfection was quantified by counting bacteria colonies from samples aspirated before and after treatment. Histopathological evaluation of the abscesses was performed to identify changes resulting from histotripsy treatment and potential collateral damage. Cavitation histotripsy was more successful in reducing the bacterial load while having a smaller treatment volume compared with boiling histotripsy. The results of this pilot study suggest focused ultrasound may lead to a technology for in situ treatment of acoustically accessible abscesses.

External Validation of an Algorithm to Predict Adjacent Musculoskeletal Infection in Pediatric Patients With Septic Arthritis.

Septic arthritis (SA) remains a potentially morbid disease in the pediatric population. Magnetic resonance imaging (MRI) is the most sensitive tool for recognizing associated osteomyelitis and intramuscular abscess, but is a limited resource. The aim of this study is to externally validate a previously developed algorithm (Rosenfeld and colleagues) to predict adjacent infection in pediatric patients diagnosed with SA. We identified 120 children under 16 with presumed SA presenting to a tertiary referral center between 2008 and 2018. Patients without confirmed SA, those with insufficient data, and patients who did not receive perioperative MRI were excluded, leaving 53 patients. The previous algorithm suggests that patient age (above 4 y), C-reactive protein (>8.9 mg/L), platelet count (<310×10cells/µL), duration of symptoms (>3 d), and absolute neutrophil count (>7.2×10cells/µL) are risk factors for adjacent infection, with 3 or more variables signifying a "positive" result. Comparing against the gold standard of MRI, the accuracy of the algorithm was validated in terms of sensitivity, specificity, likelihood ratio (LR), and positive and negative predictive value. Discrimination and calibration of this algorithm have been assessed using receiver operating curve analysis and calibration plots. The sensitivity and specificity of criteria from Rosenfeld algorithm were 73% and 44%, respectively. Receiver operating curve showed poor discrimination [area under the curve=0.54, confidence interval (CI): 0.26-0.83]. The positive predictive value was 55.9% and the negative predictive value was 63.1% with LR +1.23 (CI: 0.87-1.98) and LR -0.61 (CI 0.28-1.30). Only 53% of patients with 4 or more criteria had an adjacent infection on MRI. Examining our cohort, children with a positive MRI finding had higher mean C-reactive protein (77 vs. 122 mg/L, P=0.04) and were more likely to have waited >72 hours days between symptom onset and hospital presentation (P=0.03). Although treatment algorithms are an attractive tool to guide clinicians and resource allocation, they need to take into account the local population characteristics before routine implementation. Level IV-retrospective cohort study.

Physiological, biochemical and HSP70 and HSP90 gene expression profiles of tropical abalone Haliotis squamata in response to Vibrio alginolyticus infection

Vibrio spp. have been known responsible for fish diseases in marine and brackish‐water systems in the tropics regions. Heat shock proteins are a highly conserved protein group that is known for its rapid response to environmental stresses, including infection. This study aimed to investigate physiological and biochemical responses of tropical abalone Haliotis squamata to Vibrio alginolyticus infection. Abalones were infected with V. alginolyticus by intramuscular injection at a dose of 105,106,107 cfu/abalone. The expression of HSP70 and HSP90 genes, the activity of superoxide dismutase, phenol oxidase and catalase enzymes, histology, falling and mortality were observed at 12, 24, 48, 72, and 96 hours post‐infection (hpi). The different expression of HSPs was found in this study. While the expression of HSP70 was downregulated after infection, the expression of HSP90 was upregulated at 12 hpi and followed by downregulated after 24 hpi for 106 cfu infection, but expressed at a normal level for 105 infection treatment. The expression ofsuperoxide dismutase and catalase increased within 12 hpi, and the expression of phenol oxidase increased after 24 hpi. V. alginolyticus is virulent with LD50 of less than 105 cfu on H. squamata with an average weight of 5.13 g, and caused enlargement of hemolymph sinus and development intraepithelial and intramuscular abscesses.

The Role of Hip Arthroscopy in the Management of Acute Arthritis of Hip

Septic arthritis of hip is an orthopaedic emergency requiring early diagnosis and prompt surgical treatment to avoid grave complications like avascular necrosis and chondrolysis and post-infectious arthrosis.This is a retrospective review of 9 patients who underwent hip arthroscopy for suspected septic arthritis of hip from 2012 to 2018. Medical charts were reviewed to determine the efficacy of the use of hip arthroscopy in the diagnosis and treatment of acute hip arthritis.The age of patients ranged from 9 to 82. The mean follow-up was 29 months (1 to 49). All presented with hip pain and effusion in imaging by CT scan or ultrasonography. Fever was present in 5 out of 9 patients. Hip arthroscopy with 2 portals technique and joint lavage +/- debridement was done. Two patients had whitish suspension in the joint fluid and pathology confirmed pseudogout of hip. The remaining 7 patients were diagnosed and treated as septic hip arthritis. Only 3 had positive culture, probably related to the prior use of antibiotics. All except one responds well to arthroscopic debridement and lavage with infection eradicated, good hip motion and hip function. One patient of delayed treatment (2 weeks after onset of hip pain) had ongoing infection, requiring further arthrotomy and Girdlestone operation for uncontrolled hip infection with intramuscular abscess of vastus lateralis.Hip arthroscopy is a useful diagnostic tool in acute hip arthritis. Besides septic arthritis, monoarticular attack of psuedogout is an important differential diagnosis of acute hip pain in elderly. Early hip arthroscopy can result in rapid postoperative recovery. Arthroscopic lavage and debridement is safe and a good alternative to open arthrotomy in hip septic arthritis.

Discrimination between tuberculous and bacterial pyomyositis in magnetic resonance features

PurposeThe purpose of this study was to assess the differences of magnetic resonance features between tuberculous and bacterial pyomyositis. MethodThis is a retrospective study of patients with bacterial and tuberculous pyomyositis. We excluded patients with pyomyositis caused by actinomycosis, non-tuberculous mycobacterium, fungi, unknown of causative organism, or inadequate imaging for analysis. Magnetic resonance imaging was independently reviewed by two radiologists. ResultsOf the 136 pyomyositis patients, 71 (52.2 %) patients had bacterial pyomyositis while 65 (47.8 %) patients had tuberculous pyomyositis. Seventy-seven patients (56.6 %) had intramuscular abscess. On multivariable analysis, bacterial pyomyositis was associated with diabetes mellitus (odds ratio [OR] 3.17, 95 % confidence interval [CI] 1.30–8.24) and bone marrow involvement (OR 5.02, 95 % CI 1.21–34.4). Spinal involvement had a significantly lower likelihood of bacterial pyomyositis (OR 0.25, 95 %CI 0.11–0.54). In patients with intramuscular abscess, diabetes mellitus and hyperintense on T2-weighted images at the abscess wall had a significantly higher likelihood of bacterial pyomyositis (OR 5.21, 95 %CI 1.33–25.42 and OR 5.34, 95 %CI 1.36–24.71, respectively), whereas spinal involvement had a significantly lower likelihood of bacterial pyomyositis (OR 0.09, 95 %CI 0.02–0.30). ConclusionsMagnetic resonance imaging has modest accuracy for differentiation of tuberculous and bacterial pyomyositis. Diabetes mellitus and extraspinal pyomyositis were the predictors of bacterial pyomyositis. Presence of T2 hyperintense wall of intramuscular abscess was also the predictor of bacterial pyomyositis.