Infection and musculoskeletal conditions: Infectious myositis

Recurrent Primary Abdominal Wall Abscess: A Case Report and Review of the Literature

Primary abdominal wall abscess is extremely rare and difficult to diagnose because abdominal wall abscesses usually occur secondary to malignant tumors or inflammatory diseases. We experienced a case of an 80-year-old man with an asynchronous primary abdominal wall abscess with recurrence. Both abscesses were successfully treated with surgical drainage. A patient without any history of cancer or trauma presented to our department with right upper abdominal pain. His laboratory data showed an abnormal high inflammatory response, and computed tomography revealed a 40 × 30 mm mass formed in the rectus abdominis muscle of the upper right abdomen. The mass had no continuity with the surgical scar after cholecystectomy or intra-abdominal organs. Citrobacter diversus was detected in the culture from the mass and any epithelial components were not detected by biopsy. For the diagnosis of primary abdominal wall abscess, the patient underwent surgical drainage because antibiotic treatment was ineffective. The abscess disappeared promptly after the drainage. Thirteen months after the first treatment, another primary abdominal wall abscess was noted in the lower right abdomen. The abscess also promptly disappeared with surgical drainage. Primary abdominal wall abscess is difficult to diagnose because of its rarity. Prompt diagnosis and drainage are important to prevent exacerbation.

A case report of acute suppurative thyroiditis caused by Clostridium perfringens

A 42-year-old woman inadvertently discovered a neck mass, which caused pain. Initially, she was treated with antibiotics at a local clinic; however, this treatment did not alleviate the symptoms. She visited the authors' outpatient clinic for further treatment and underwent thyroid ultrasonography, which revealed a mixed echo nodule. On day 4 after admission, surgery was performed to remove the diseased thyroid tissue and levofloxacin (0.4 g/day) was infused. Bacterial culture confirmed infection with Clostridium perfringens. Subsequently, the treatment was switched to ceftriaxone sodium (2 g/day) according to the results of the drug sensitivity test. Following treatment, the patient recovered fully and was discharged. She was then followed up with after discharge. Ultrasonography, laboratory testing and clinical manifestations did not indicate obvious abnormalities.

Impaired muscle stem cell function and abnormal myogenesis in acquired myopathies

Skeletal muscle possesses a high plasticity and a remarkable regenerative capacity that relies mainly on muscle stem cells (MuSCs). Molecular and cellular components of the MuSC niche, such as immune cells, play key roles to coordinate MuSC function and to orchestrate muscle regeneration. An abnormal infiltration of immune cells and/or imbalance of pro- and anti-inflammatory cytokines could lead to MuSC dysfunctions that could have long lasting effects on muscle function. Different genetic variants were shown to cause muscular dystrophies that intrinsically compromise MuSC function and/or disturb their microenvironment leading to impaired muscle regeneration that contributes to disease progression. Alternatively, many acquired myopathies caused by comorbidities (e.g., cardiopulmonary or kidney diseases), chronic inflammation/infection, or side effects of different drugs can also perturb MuSC function and their microenvironment. The goal of this review is to comprehensively summarize the current knowledge on acquired myopathies and their impact on MuSC function. We further describe potential therapeutic strategies to restore MuSC regenerative capacity.

Group A Streptococcus necrotising myositis of the limbs secondary to cavitating pneumonia

Necrotising myositis is a rare complication of Group A Streptococcus infection requiring early and aggressive surgical management to prevent mortality. However, early diagnosis is difficult due to non-specific initial presentation and a low index of clinical suspicion given the paucity of cases. We highlight these challenges and present a case of a 22-year-old woman presenting with cough, fever and severe limb pain refractory to analgesia during the COVID-19 pandemic. We outline potential confounding factors that can delay intervention and offer diagnostic tools that can aid clinical diagnosis of necrotising myositis. In reporting this case, we hope to raise awareness among clinicians to avoid these pitfalls.

Myositis associated with Salmonella paratyphi A bacteremia appears to be common

Background

Fever and severe myalgia in a tropical country like India bring to mind leptospirosis, rickettsioses, dengue, and other viral fevers. Enteric fever is widely prevalent in Asia, but myositis has not been previously described in Salmonella paratyphi A bacteremia.

Materials and Methods

Retrospectively, we recruited patients with enteric fever admitted to our treating unit over a 6-month period. Demography, historical, clinical, and laboratory data were obtained. Data of culture-positive S. paratyphi A patients were analyzed and were compared with those patients with culture-negative enteric fever.

Results

Forty-three cases were found in total with 19 of S. paratyphi A bacteremia. Elevations in creatine kinase (CK) ranged from one-and-half to six times normal. Forty-seven percent had thrombocytopenia and alanine transaminase elevations, while aspartate transaminase elevations were seen in 17 patients, which corresponded to those with elevated CK levels.

Conclusions

Myositis associated with S. typhi and S. paratyphi is very rare and is more often due to non-typhoidal Salmonellae. Elevated creatine kinase was seen in most of our patients with S. paratyphi A bacteremia. Such myositis has not been described previously and hence, myalgia with fever in a tropical country could be a harbinger of paratyphoid fever.

Subscapularis pyomyositis: a rare presentation of shoulder pain

We present a rare case of a subscapularis pyomyositis in a 38-year-old woman and examine the diagnostic and surgical challenges posed. History and examination features were similar to that of septic shoulder arthritis without overlying features of warmth or erythema. Serological markers revealed a C-reactive protein of 221 mg/L and white cell count of 11.1×10⁹/L. A dry shoulder aspirate was obtained. Contrast-enhanced MRI demonstrated a peripheral rim-enhancing lesion within the subscapularis muscle belly with lack of central enhancement. These features are consistently seen with an infective aetiology. A deltopectoral approach to surgical drainage was utilised and subsequent fluid cultures grew Panton-Valentine Leukocidin positive Staphylococcus aureus species. This rare bacterium is associated with an increased risk of osteomyelitis and despite making a full recovery, the patient was advised to reattend if any future shoulder pain was encountered.

MR Imaging of Atraumatic Muscle Disorders

Atraumatic disorders of skeletal muscles include congenital variants; inherited myopathies; acquired inflammatory, infectious, or ischemic disorders; neoplastic diseases; and conditions leading to muscle atrophy. These have overlapping appearances at magnetic resonance (MR) imaging and are challenging for the radiologist to differentiate. The authors organize muscle disorders into four MR imaging patterns: (a) abnormal anatomy with normal signal intensity, (b) edema/inflammation, (c) mass, and (d) atrophy, highlighting each of their key clinical and imaging findings. Anatomic muscle variants, while common, do not produce signal intensity alterations and therefore are easily overlooked. Muscle edema is the most common pattern but is nonspecific, with a broad differential diagnosis. Autoimmune, paraneoplastic, and drug-induced myositis tend to be symmetric, whereas infection, radiation-induced injury, and myonecrosis are focal asymmetric processes. Architectural distortion in the setting of muscle edema suggests one of these latter processes. Intramuscular masses include primary neoplasms, metastases, and several benign masslike lesions that simulate malignancy. Some lesions, such as lipomas, low-flow vascular malformations, fibromatoses, and subacute hematomas, are distinctive, but many intramuscular masses ultimately require a biopsy for definitive diagnosis. Atrophy is the irreversible end result of any muscle disease of sufficient severity and is the dominant finding in disorders such as the muscular dystrophies, denervation myopathy, and sarcopenia. This imaging-based classification, in correlation with clinical and laboratory data, will aid the radiologist in interpreting MR imaging findings in patients with atraumatic muscle disorders. ^©RSNA, 2018.

Extensive pyomyositis of vastus muscles

We report a case study on a patient who presented with low back and thigh pain of one month duration. He was eventually diagnosed with left thigh pyomyositis. Tissue from thigh grew Staphylococcus aureus. With commencement of antibiotics and surgical drainage, patient made recovery despite prolonged hospital stay. The underlying mechanism of the extensive abscess accompanied by lack of systemic symptoms; is related to relative immunocompromised state of having underlying diabetes mellitus.

Pyomyositis in Children

Primary pyomyositis in children is prevalent in the tropics and increasingly being recognised from temperate regions. Staphylococcus aureus remains the principle causative organism worldwide, while proportion of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is on rise. Commonly involved groups are around the pelvis and lower limbs. Clinical presentation depends on the stage of disease, most commonly a child presenting with limping with fever. Early diagnosis and management are crucial. The investigation of choice is MRI scan. Appropriate antibiotic treatment should be instituted at the earliest opportunity along with drainage. Majority of patients show excellent and complete recovery with no long-term complications once treatment is started early. A high level of awareness and suspicion of this condition is warranted from all paediatric clinicians.

Recurrent Fusobacterium pyogenic myositis of the rotator cuff A case report of recurrent Fusobacterium pyogenic myositis of the rotator cuff

Pyogenic myositis is uncommon. It normally affects the large muscle groups in the lower limb or trunk and the most common causative organism is Staphylococcus aureus. We present a case of an immunocompetent man who, unusually, had a recurring form of the disease in subscapularis and teres minor. The causative organism was also highly unusual (Fusobacterium).

[Primary tuberculous pyomyositis in an immunocompetent patient: report of a case]

L'atteinte du muscle strié au cours de la tuberculose chez un sujet immunodéprimé ou à partir de l'extension d'un foyer ostéo-articulaire de voisinage est rare mais bien connue. Toutefois, l'atteinte primitive est exceptionnelle ainsi que celle chez un sujet immunocompétent. L'imagerie par résonnance magnétique (IRM) est d'un grand apport pour le diagnostic avec une excellente sensibilité. Nous rapportons un cas de pyomyosite tuberculeuse primitive du mollet chez une patiente non immunodéprimé tout en précisant l'apport de l'IRM.

Classification, diagnosis, and management of idiopathic inflammatory myopathies

The detection and characterization of a large array of autoantibodies, including at least 8 different antisynthetase, anti-SRP, -200/100 (HMGCR), -Mi-2, -CADM-140 (MDA5), -SAE, -p155, -MJ (NXP-2), and -PMS1, frequently associated with distinct and well-defined clinicopathological features, allowed for significant improvement in the definition and diagnosis of idiopathic inflammatory myopathies (IIM). Classification remains difficult, with lingering divergence between the different specialties involved in IIM care, but several categories clearly stand out, including dermatomyositis (DM), overlap myositis (OM), polymyositis, necrotizing myositis, and sporadic inclusion body myositis (s-IBM). Biopsy and histological analysis remain crucial, particularly in the absence of autoantibodies, to accurately specify the diagnosis and rule out mimics such as muscular dystrophies and metabolic myopathies. Numerous infectious agents (in particular human immunodeficiency virus and human T cell lymphotrophic virus-1) and drugs (statins, tumor necrosis factor inhibitors, and proton pump inhibitors) can cause mimic IIM that must also be excluded. Pharmacological treatment, in addition to glucocorticoids and immunoglobulins, now includes mycophenolate mofetil and rituximab, which proved helpful in resistant cases, particularly rituximab in DM and OM. Exercise, initially seen as potentially deleterious, recently was shown to be efficacious and safe. IIM can thus be reasonably well controlled in most cases, although aggressive disease remains refractory to treatment, including some cases of necrotizing myopathy. Sporadic IBM still seems resistant to all medications tested to date.

Primary pyomyositis: an unusual presentation in an older patient with no recognised risk factors

Primary pyomyositis is a subacute deep bacterial infection of skeletal muscle. It is typically seen in tropical countries with Staphylococcus aureus being the commonest pathogen. Immunocompromised states and trauma are associated with cases in temperate climates where there is an increasing incidence, typically in children and young adults. However, the authors present a case of primary pyomyositis in a previously healthy 80-year-old female. The authors highlight the potential difficulties in early diagnosis of this rare condition in the UK indicating the need for early MRI imaging and the low sensitivity of blood cultures and serum creatine kinase measurements. Treatment, including early surgical drainage and appropriate antibiotic therapy, is discussed.

Streptococcal necrotising myositis of obturator internus and piriformis in a type 2 diabetic patient presenting as sepsis of unknown origin

This report describes a case of necrotising myositis of the obturator internus and piriformis muscles. Necrotising myositis is a rare result of group A streptococcal infection. It is usually fatal and has not been described previously in the obturator internus and piriformis. We describe how, following presentation to an emergency department, rapid diagnosis was arrived at by clinically guided radiological investigation. The report considers the possible aetiology of the condition, the diagnosis and its management, and reviews the relevant literature.

Parasitic infections and myositis

Infectious myositis may be caused by a wide variety of bacterial, fungal, viral, and parasitic agents. Parasitic myositis is most commonly a result of trichinosis, cystericercosis, or toxoplasmosis, but other parasites may be involved. A parasitic cause of myositis is suggested by history of residence or travel to endemic area and presence of eosinophilia. The diagnosis of parasitic myositis is suggested by the clinical picture and radiologic imaging, and the etiologic agent is confirmed by parasitologic, serologic, and molecular methods, together with histopathologic examination of tissue biopsies. Therapy is based on the clinical presentation and the underlying pathogen. Drug resistance should be put into consideration in different geographic areas, and it can be avoided through the proper use of anti-parasitic drugs.

Primary pelvic pyomyositis in a neonate

Primary pyomyositis is a bacterial infection occurring in skeletal muscle with no obvious local or adjacent cause. It is classically an infection of the tropics, although it is reported in temperate climates with increasing frequency. Tropical pyomyositis occurs predominantly in children aged between 2 and 5 and in adults aged between 20 and 45 years, whereas most temperate pyomyositis cases occur in adults. Using a magnetic resonance imaging scan, we made the diagnosis of staphylococcal pelvic pyomyositis in a Swiss term-born infant with an initial working diagnosis of septic hip osteoarthritis.

Piriformis pyomyositis: a report of three cases

Pyomyositis is a subacute infection of skeletal muscles. It can be life-threatening if diagnosis and treatment are delayed. Only 5 cases of isolated piriformis pyomyositis have been reported. We report signs and symptoms of piriformis pyomyositis in 3 women who were treated mainly with antibiotics. Computed tomography is useful in making the diagnosis. Early diagnosis and treatment may avoid surgical treatment and reduce mortality.

Necrotizing soft tissue infections

PURPOSE OF REVIEW

The purpose of this review is to consider recent advances in the definition, pathogenesis, diagnostic criteria, and treatment of necrotizing soft tissue infections.

RECENT FINDINGS

The efficacy of early surgical debridement combined with antimicrobial therapy, close monitoring and physiologic support is strongly demonstrated. Novel therapeutic strategies including vacuum-assisted wound-closure therapy and intravenous immunoglobulin have been described.

SUMMARY

Necrotizing soft-tissue infection is a rare infection of the subcutaneous tissue and fascia that is often associated with sepsis and can progress rapidly with a possible fatal outcome. Although the cause is not yet understood fully, patients often have a prior history of a small, trivial trauma, wound, or scratch. Establishing the diagnosis can be the main challenge in treating patients, and knowledge of all available tools is key for early and accurate diagnosis.