Imaging on pelvic pyomyositis in children related to pathogenesis

Imaging of Musculoskeletal Soft-Tissue Infections in Clinical Practice: A Comprehensive Updated Review

Musculoskeletal soft-tissue infections include a wide range of clinical conditions that are commonly encountered in both emergency departments and non-emergency clinical settings. Since clinical signs, symptoms, and even laboratory tests can be unremarkable or non-specific, imaging plays a key role in many cases. MRI is considered the most comprehensive and sensitive imaging tool available for the assessment of musculoskeletal infections. Ultrasound is a fundamental tool, especially for the evaluation of superficially located diseases and for US-guided interventional procedures, such as biopsy, needle-aspiration, and drainage. Conventional radiographs can be very helpful, especially for the detection of foreign bodies and in cases of infections with delayed diagnosis displaying bone involvement. This review article aims to provide a comprehensive overview of the radiological tools available and the imaging features of the most common musculoskeletal soft-tissue infections, including cellulitis, necrotizing and non-necrotizing fasciitis, foreign bodies, abscess, pyomyositis, infectious tenosynovitis, and bursitis.

Pelvic Pyomyositis in Childhood: Clinical and Radiological Findings in a Tertiary Pediatric Center

Pyomyositis (PM) is an infrequent but increasing bacterial infection of the skeletal muscle, with muscles of the pelvis and thigh frequently involved. The diagnosis is often challenging, especially when a deep muscle is affected. We present a single-center pediatric cohort affected by pelvic PM. A retrospective analysis was performed, including children admitted to Meyer Children’s Hospital between 2010 and 2020. Demographic, anamnestic, clinical, laboratory, radiological and management data were collected. Forty-seven patients (range 8 days–16.5 years, 66% males) were selected. Pain (64%), functional limitations (40%) and fever (38%) were the most common presenting symptoms; 11% developed sepsis. The median time to reach the diagnosis was 5 days (IQR 3–9). Staphylococcus aureus was the most common organism (30%), Methicillin-Resistant S aureus (MRSA) in 14%. PM was associated with osteomyelitis (17%), arthritis (19%) or both (45%). The infection was multifocal in 87% of children and determined abscesses in 44% (40% multiple). Pelvic MRI scan, including diffusion-weighted imaging (DWI), always showed abnormalities when performed. Clinical and laboratory findings in pelvic PM are unspecific, especially in infancy. Nevertheless, the infection may be severe, and the suspicion should be higher. MRI is the most useful radiological technique, and DWI sequence could reveal insidious infections.

Hip pain in childhood

Abstract Hip pain in a child can have infectious, inflammatory, traumatic, neoplastic, or developmental causes, which can make the diagnosis challenging. Meticulous history taking and a detailed clinical examination guide the radiological investigation. In this article, we address some of the main causes of hip pain in childhood and their findings on diagnostic imaging.

Multifocal Οsteomyelitis Localization after Pyomyositis in Children: Importance of Timely Response

Pyomyositis is a rare bacterial infection that used to prevail in tropical areas for the past century. Nowadays though, more and more cases are reported in high-temperature climate areas. Diagnosis is often delayed due to the variance in clinical presentation, the challenging nature of physical examination of a child, and lack of specific laboratory investigating tools. When the diagnosis is delayed, the outcome may be unpredictable. Multifocal localization through hematogenous or direct spread that may affect the skeletal bone tissue is common. Timely diagnosis and response is a race against septic shock.

We present a case series of seven children diagnosed with pyomyositis due to Staphylococcus aureus. High or less clinical suspicion has obviously affected the final outcome since two patients who were not treated in time were subjected to a life-threatening hazard. Five patients who were diagnosed and treated within the first three days after initiation of their symptoms had a predictable and good outcome without complications.

Obturator externus abscess in a 9-year-old child: A case report and literature review

RATIONALE

Obturator pyomyositis is a rare condition in children. Diagnosis is often delayed because of its rarity, and the vagaries of its presentation cause it to be easily be missed. Physicians should therefore familiarize themselves with this condition and consider it as a possible differential diagnosis in patients presenting with an acutely painful hip. Inflammatory syndrome is also frequent among sufferers and the MRI is a very sensitive diagnostic tool for obturator pyomyositis. Additionally, joint fluid aspirations and blood cultures are also useful in identifying the pathogen. The appropriate antibiotic therapy provides a rapid regression of symptoms during the early stage of pyomyositis. In cases of MRI-confirmed abscess, surgical treatment is indicated.

PATIENT CONCERNS

Our report focuses on a case of obturator pyomyositis in a 9-year-old boy. The child was febrile for 5 days and could only manage to walk a few steps. His hip range of motion was restricted in all directions. In addition, the patient had presented pain and swelling of his right elbow for a day, with a restriction of motion in the joint. There was a clear inflammatory syndrome. A diagnosis of hip and elbow septic arthritis was suspected, and the child underwent joint aspiration of the both cited joints. The aspiration of the elbow returned pus. Conversely, no effusion was found in the hip aspiration. The administration of empiric intravenous antibiotherapy was started.

DIAGNOSES

An MRI revealed an osteomyelitis of the ischio-pubic area associated with a subperiosteal abscess.

INTERVENTIONS

Subsequently, 3 days after elbow arthrotomy, a surgical treatment was performed on the patient's right hip in order to evacuate the subperiosteal abscess and muscular collection because of the persistence of the patient's symptoms and inflammatory syndrome despite susceptible intravenous antibiotics. Postsurgery the patient showed steady improvement.

LESSONS

Such cases demonstrate how diagnosis can be difficult because pelvic pyomyositis is often mistaken for more common pathologies such as septic arthritis, osteomyelitis, or appendicitis. This may delay the diagnosis or refer misdiagnosis. We discuss this rare infection in light of the literature with particular reference to its incidence, clinical features, bacteriological etiology, biological, and radiological presentation, and above all, its treatment.

Pediatric pelvic pyomyositis: initial MRI can be misleading

Pelvic pyomyositis is an infection of the skeletal muscles around the hip joint. Fever, hip pain, limp, and leukocytosis are common; however, the clinical picture is often vague. MRI is the current gold-standard imaging for pyomyositis. No studies in the current literature have reported an unremarkable initial MRI in a patient with symptomatic pyomyositis. An adolescent female presented with symptomatic pelvic pyomyositis, but admission MRI was normal. A follow-up MRI indicated development of pelvic pyomyositis. The patient was successfully managed nonoperatively. The initial MRI in pyomyositis can be misleading. Patients should be admitted and MRI should be repeated, as indicated clinically.

Pyomyositis in childhood-systemic lupus erythematosus

Pyomyositis is a pyogenic infection of skeletal muscle that arises from hematogenous spread and usually presents with localized abscess. This muscle infection has been rarely reported in adult-onset systemic lupus erythematous and, to the best of our knowledge, has not been diagnosed in pediatric lupus population. Among our childhood-onset systemic lupus erythematous population, including 289 patients, one presented pyomyositis. This patient was diagnosed with childhood-onset systemic lupus erythematous at the age of 10 years-old. After six years, while being treated with prednisone, azathioprine and hydroxychloroquine, she was hospitalized due to a 30-day history of insidious pain in the left thigh and no apparent trauma or fever were reported. Her physical examination showed muscle tenderness and woody induration. Laboratory tests revealed anemia, increased acute phase reactants and normal muscle enzymes. Computer tomography of the left thigh showed collection on the middle third of the vastus intermedius, suggesting purulent stage of pyomyositis. Treatment with broad-spectrum antibiotic was initiated, leading to a complete clinical resolution. In conclusion, we described the first case of pyomyositis during childhood in pediatric lupus population. This report reinforces that the presence of localized muscle pain in immunocompromised patients, even without elevation of muscle enzymes, should raise the suspicion of pyomyositis. A prompt antibiotic therapy is strongly recommended.

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.

Obturator externus pyomyositis

Pyomyositis of the obturator externus muscle is a rare cause of limp and hip pain in children. The exact etiology of the condition remains poorly understood, although a mechanism of transient bacteremia in association with increased muscle susceptibility has been proposed. This case describes the course of a rather than 1 child from presentation to diagnosis and demonstrates the requirement for magnetic resonance imaging in establishing a diagnosis.

Pyogenic sacroiliitis and pyomyositis in a patient with systemic lupus erythematous

Pyogenic sacroiliitis and pyomyositis are uncommon infectious diseases and their diagnoses are often delayed. They are typically seen in children and young adults and are rare in middle-aged people especially in those affected by rheumatic diseases. We present the first case of a Staphylococcus aureus related pyogenic sacroiliitis associated with iliacus and gluteal pyomyositis occurring in a patient with systemic lupus erythematosus. Antibiotic treatment was administered for a total of 6 weeks with a total recovery. Pyogenic sacroiliitis and pyomyositis, although remaining rare events, should be remembered as severe complications in immunosuppressed patients with inflammatory diseases. Early clinical suspicion, imaging diagnosis, and adequate therapy are decisive for the satisfactory outcome.

Paediatric Iliopsoas abscess: A case report

Introduction: Iliopsoas abscess is an uncommon condition in the paediatric population. The clinical presentation is variable and may be confused with other conditions such as septic arthritis, osteomyelitis and appendicular abscess. A suspicion of iliopsoas abscess requires a prompt diagnosis so that rapid management and treatment can be undertaken. Discussion: This case describes the presence of an iliopsoas abscess in a paediatric patient presenting to the emergency department within a rural community. Due to the variability in clinical presentation imaging studies are necessary to distinguish an iliopsoas abscess from other inflammatory processes. Ultrasound is often the modality of choice. Imaging guided percutaneous drainage and/or aspiration and the administration of intravenous antibiotics are minimally invasive modern techniques providing a safe treatment options in the presence of an iliopsoas abscess. Conclusion: Iliopsoas abscess is an uncommon condition in the paediatric population. Due to the variability in clinical presentation, imaging, and in particular, ultrasound play a vital role in the diagnosis of cases with a high suspicion of abscess formation. Accurate diagnosis leads to a rapid treatment plan, avoiding further insult.

Osteomyelitis and beyond

Musculoskeletal infections are a cause of considerable morbidity in children. Symptoms and signs are often nonspecific, and imaging is needed to define the anatomical location of infected tissue or fluid collections for diagnostic aspiration or biopsy. Prompt diagnosis and precise localization of the infection site has become even more imperative with the emergence and dissemination of highly invasive organisms such as community-acquired Staphylococcus aureus. Although radiography, bone scintigraphy and US continue to play a role, MRI is now the preferred imaging modality for definitive evaluation of pediatric musculoskeletal infections because of its capability of simultaneously assessing the osseous, articular and muscular structures without ionizing radiation exposure. This article focuses on the imaging characteristics of osteomyelitis, septic arthritis and pyomyositis and the differentiating features of potential mimics of infection.

Primary pyomyositis of the pelvis in children: a retrospective review of 8 cases

Primary pyomyositis of the pelvic musculature is a condition rarely seen in temperate climates, although its frequency has been increasing in the United States. The condition should be considered in the initial differential diagnosis of an adolescent presenting with fever, difficulty ambulating, and hip pain. This is a retrospective review of 8 cases of primary pelvic pyomyositis in patients aged 18 years or younger who were treated at the Children's Medical Center in Augusta, Georgia. The site of infection was the obturator internus in the majority of the cases (5). The site was the gluteus, iliopsoas, and iliacus in 1 case each. Four patients who were diagnosed early responded to intravenous antibiotics with no need for further intervention. Two patients required incision and drainage of an abscess combined with antibiotics. Two patients had prolonged hospital courses requiring intensive unit care and mechanical ventilation. Blood cultures were positive in 87.5% of patients, and all patients presented with elevated acute phase reactants. One of the most difficult diagnostic aspects of presentation is an inconclusive symptom profile. It is noteworthy that patients with pelvic pyomyositis may present with limited range of motion in a specific plane (the motion placing the infected muscle on stretch) vs global limited range of motion of the joint as is commonly seen in septic arthritis. Early diagnosis is essential to prevent systemic illness and complications associated with this condition. Magnetic resonance imaging with gadolinium is helpful to diagnose and guide treatment.

The conservative management of primary pyomyositis abscess in children: case series and review of the literature

Pyomyositis is a primary pyogenic infection in skeletal muscle, often progressing to abscess formation. It is rare in temperate climates and generally deep-seated within the pelvis with nonspecific clinical features, making diagnosis difficult. Magnetic resonance imaging (MRI) is highly sensitive for muscle inflammation and fluid collection, and with its increasing availability is now the investigation of choice. Treatment of pyomyositis abscess has traditionally been with incision and drainage or guided aspiration followed by a prolonged course of antibiotics, although there are sporadic reports of cases treated successfully with antibiotics alone. Our aim was to describe our own experience with the treatment of pyomyositis abscess in children. From our 20-year database of over 16,000 paediatric orthopaedic admissions, we identified only three cases with MRI-confirmed pyomyositis abscess. These were all in boys (aged 2-12 years) and affected the gluteal, piriformis and adductor muscles. Despite the organisms not being identified, each patient was treated successfully with a short (4-7 days) course of intravenous antibiotics followed by 2-6 weeks of oral therapy. There were no recurrences or complications and all made a full recovery. In conclusion, we propose that uncomplicated pyomyositis abscess in children may usually be managed conservatively without the need for open or percutaneous drainage.