Pyomyositis in children: analysis of 31 cases

Clinical Characteristics and Management of Children and Adolescents Hospitalized With Pyomyositis

BACKGROUND

Pyomyositis, a bacterial muscle infection, is an important differential diagnosis in children and adolescents with musculoskeletal pain. In contrast to tropical regions, it is rarely recognized in temperate countries, but incidence is increasing and major studies are missing.

METHODS

This retrospective multicenter study included patients <18 years of age hospitalized with pyomyositis in 11 Swiss children's hospitals between January 2010 and December 2022. Cases were identified by ICD-10 code (Myositis; M60-M60.9), and data was extracted from electronic hospital records.

RESULTS

Of 331 patients identified, 102 fulfilled the case definition. Patient age at presentation ranged from 2 weeks to 17 years (median 8 years). The majority had no underlying illness and all presented with fever and localized pain. At the respective site of pyomyositis, 100 (98%) had impaired movement and 39 (38%) presented with local swelling. Pelvic (57%) and leg (28%) muscles were mostly affected. Blood or tissue cultures were obtained in 94 (92%) and 59 (57%) patients, respectively. Of those, 55 (58%) blood and 52 (88%) tissue cultures were positive, mainly for Staphylococcus aureus (35 and 19, respectively) and Streptococcus pyogene s (12 and 15, respectively). All patients received antibiotic treatment during hospitalization for a median of 10 days (interquartile range: 7-17), followed by outpatient treatment for a further median of 16 days (interquartile range: 11-22) in 95 (93%) patients. Fifty-nine (57%) patients required surgery.

CONCLUSIONS

Pyomyositis is a challenging diagnosis that requires a high level of awareness. Blood and/or tissue cultures revealed S. aureus and S. pyogenes as the predominant causative agents.

A fatal case of paediatric post-traumatic pyomyositis

A 6-year-old girl was brought to the emergency department with a history of an accidental fall a few days earlier. She presented with a fever, cough and constipation. Sars-CoV-2 infection being suspected, she was transferred to a paediatric facility for Covid-positive patients. During the diagnostic process, the clinical picture suddenly deteriorated with the development of bradycardia, tachypnea and altered sensorium. Despite cardiopulmonary resuscitation attempts, the child died about 16 hours after admission to the emergency department. A judicial forensic autopsy was performed that concluded that her death was due to multiple acute pulmonary, cardiac and renal infarctions secondary to septic thromboembolism in the course of post-traumatic bacterial necrotizing pyomyositis of the right ileo-psoas muscle.

Meticillin-susceptible Staphylococcus aureus pyomyositis and cellulitis in right thigh of a 15-year-old boy: a case study

Pyomyositis is a purulent infection of striated muscle and postoperative management remains the mainstay. If delayed primary wound closure is not managed in a timely manner, it often results in recurrent infection and sinus tract creation. Cavity wounds with sinus formation are known to complicate treatment, are problematic to manage and persist for long periods of time. The aim of this case report is to present the challenges in the assessment and management of a sinus tract with deep cavity wound, between the vastus lateralis and biceps femoris muscles, originating from liquefaction of a haematoma. Our review of the literature revealed limited research evidence in the management of deep cavity wounds. This is a rare case where the sinus tract route which leads to the rim-shaped cavity is embedded deep between the muscles, posing a high risk of recurrent infection from the premature closure of the wound tract. Successful management was attributed to: the accuracy in the initial wound assessment; appropriate dressing plans; the rationale for each action; and an outcome goal as each treatment progressed. Daily dressing change and reassessment of the wound was required to ensure progress and to address any complications in a timely manner. Finally, concerns of the patient and their family and regular discussions on the treatment plans are important to encourage adherence with management goals.

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.

Obturator pyomyositis and labium majus cellulitis: A case report and literature review

Pyomyositis is a rare, subacute, deep bacterial infection of the skeletal muscle. When treatment is delayed, pyomyositis causes abscess formation and progresses to sepsis; therefore, its early diagnosis is important. However, the clinical presentation and laboratory findings of pyomyositis are not specific; hence, diagnosis often takes time. We encountered the case of a girl with obturator pyomyositis and redness and swelling of the labium majus, which we considered as potentially important symptoms for distinguishing obturator pyomyositis from septic hip arthritis. An 8-year-old Japanese girl presented to our hospital with fever and right hip pain. On physical examination, she had redness and swelling of the right labium majus and a right limp. She was diagnosed with obturator pyomyositis and labium majus cellulitis with magnetic resonance imaging. Her clinical presentation markedly improved after starting antibiotic therapy with intravenous cefazolin for 2 weeks and oral cefaclor for 1 week. Improvement in the inflammation of the obturator muscle and labium majus was confirmed with follow-up magnetic resonance imaging. She recovered fully with no long-term sequelae. In conclusion, obturator pyomyositis rather than septic hip arthritis should be considered in children with a limp and hip and perineal pain, particularly girls with redness and swelling of the labium majus. In addition, imaging studies, including magnetic resonance imaging, should be performed for early diagnosis.

Primary pyomyositis in an infant following one-day afebrile upper limb monoplegia

Background : Pyomyositis is a subacute bacterial infection of the skeletal muscles. Its most common features are fever, muscle swelling, and focal pain. There have been insufficient data regarding pyomyositis in healthy infants. Case report : A one-month-old boy presented with an impairment of his left arm movement. He was well-nourished and not under any apparent distress. His vital signs were within the normal limits but neurological examination revealed left forearm paralysis. Physical examination showed no abnormal findings in the region from the left shoulder joint to the fingertips. Considering these factors, an intracranial pathology was initially suspected. However, he developed a fever, regular tachycardia, and swelling in the left forearm. Magnetic resonance imaging revealed inflammation in the left forearm muscles. He was diagnosed with bacterial myositis and started on intravenous antibiotics. On the 17th day, he was discharged with oral antibiotic treatment, which was completed over 25 days without any sequelae nor relapse. Conclusion : Here we report the case of Japanese primary pyomyositis following one-day afebrile upper limb monoplegia in an infant. Even when infants exhibit afebrile symptoms, a bacterial infection should be suspected. J. Med. Invest. 68 : 372-375, August, 2021.

Primary Bacterial Pyomyositis in Children: A Systematic Review

BACKGROUND

Tropical pyomyositis has had a recent increase in the United States, Europe, and other nontropical areas. The purpose of this study was to provide an accurate description of the demographics, presenting features, sites of involvement, microbiology, imaging modalities, medical and surgical management, complications, and predictors of clinical course.

METHODS

We searched PubMed, Cochrane, Web of Science Collection, Scopus, and Embase databases yielding 156 studies. Of these, 23 articles were selected for statistical analysis.

RESULTS

The average age at presentation was 8.4±1.9 years with males more commonly affected. Fever, painful limp, and localized pain were the most common presenting symptoms. Pelvis, lower extremity, trunk and spine, in descending order, were the most commonly affected locations. Iliopsoas, obturator musculature, and gluteus musculature were the most commonly affected muscle groups. The mean time to diagnosis was 6.6±3.05 days. Staphylococcus aureus was the most common offending organism. The mean length of hospital stay was 12.0±4.6 days. Medical management alone was successful in 40% of cases (143/361) with an average duration of 9.5±4.0 and 22.7±7.2 days of intravenous and oral antibiotics, respectively. Surgical management consisted of open drainage in 91.3% (199/218) or percutaneous drainage in 8.7% (19/218) of cases. Painful limp, fever, and larger values of white cell count and erythrocyte sedimentation rate were associated with an increased need for surgery. Obturator and calf muscle involvement were strongly associated with multifocal involvement. There were 42 complications in 41 patients (11.3%). Methicillin-resistant S. aureus was associated with an increased risk of complications. The most common complications were osteomyelitis, septicemia, and septic arthritis.

CONCLUSIONS

Primary pyomyositis should be considered in cases suggesting pediatric infection. Magnetic resonance imaging is the most commonly used imaging modality; however, ultrasound is useful given its accessibility and low cost. Medical management alone can be successful, but surgical treatment is often needed. The prognosis is favorable. Early diagnosis, appropriate medical management, and potential surgical drainage are required for effective treatment.

LEVEL OF EVIDENCE

Level IV-systematic review.

Pyomyositis in the United States 2002-2014

OBJECTIVES

Primary pyomyositis is a bacterial infection of skeletal muscle first recognized in tropical regions of the world but needing characterization in temperate climates.

METHODS

This population-based study used the Healthcare Utilization Project/Nationwide Inpatient Sample database to characterize the trends of pyomyositis admissions in the United States from 2002-2014 using ICD-9 diagnostic codes.

RESULTS

We found a concerning more than three-fold increase in the incident pyomyositis admissions over our study period. The median length of stay was over twice as long compared to other hospitalized patients. Patients with pyomyositis were younger and more likely to be male and Black. There were more cases in the West and South compared to Midwest and Northeast. Age-adjusted odds ratios revealed significant association of pyomyositis with HIV, types 1 and 2 diabetes mellitus, hematologic malignancy, organ transplant, malnutrition, chronic kidney disease, obesity, and rheumatoid arthritis. The most commonly identified bacterial diagnosis was Staphylococcus aureus. Pseudomonas species were the most commonly identified gram-negative bacteria.

CONCLUSION

This nationwide review of pyomyositis in the United States suggests a concerning increase in incidence and provides information on the trends, demographics, risk factors, and causative organisms for pyomyositis in the United States.

Fever and Hip Pain: Not Always Due to a Septic Hip

Hip pain in febrile children always raises concern for septic arthritis. Pyomyositis is a rare cause of hip pain. Because it involves muscles around the joint, it may have a similar presentation as a septic hip. This entity therefore has the potential for posing a diagnostic dilemma when physicians face a limping child with fever. We report a child who presented with fever and hip pain and has pyomyositis of the obturator internus muscle. This case underscores the need to consider the possibility of alternative etiologies in a limping child.

Primary obturator internus and obturator externus pyomyositis

Background

Pyomyositis is a rare condition in immune competent patients and is usually seen in tropical countries. Pyomyositis of obturator muscles in particular is an extremely rare condition, which causes hip pain and mimics septic arthritis.

Case Report:

This is a case report of a 9-year-old boy without an underlying disease or a compromised immune system, who presented with knee pain that progressed to hip pain and inability to bear weight. He was diagnosed initially with septic arthritis of the hip and underwent unnecessary hip exploration surgery. Magnetic resonance imaging scan was performed postoperatively and showed pyomyositis of obturator internus and obturator externus muscles. He was managed medically and had a good outcome.

Conclusions:

A greater awareness of this emergency condition is necessary to prevent misdiagnosis, unnecessary surgical intervention, and to avoid the devastating possible complications of delayed diagnosis.

Primary obturator-muscle pyomyositis in immunocompetent children

PURPOSE

Primary pyomyositis in immunocompetent children in non-tropical regions (countries with temperate climates) is very uncommon. It is rarely found in the intrapelvic muscles, and even more rarely in the obturator muscles. We try to draw attention to the potential occurrence in these conditions.

METHODS

Five new cases of primary obturator-muscle pyomyositis in immunocompetent children aged between 6 and 11 years in a temperate climate are presented. They present with symptoms as follows: fever, pain (thigh, abdominal, inguinal, and/or hip pain), and limp. Three of them had no hip movement limitation. All of them had tenderness in the perineum zone.

RESULTS

Laboratory tests may reveal high erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) counts, but depend on the length of diagnostic delay. The evolution time oscillated from 1 to 5 days. Fever and limp disappearance depends on the evolution time previous to the onset of the antibiotics administration. In 4 out of 5 patients, Staphylococcus aureus was present in the blood cultures. In all cases of obturator-muscle pyomyositis, diagnosis was confirmed using computed tomography (CT) scan (one) and/or magnetic resonance imaging (MRI) (four).

CONCLUSIONS

Obturator-muscle pyomyositis is aimed at emphasizing the diagnostic difficulties associated with the condition, due to its deep location and to the fact that the disease presents with multiple manifestations that may initially cause confusion, since they mimic other conditions occurring in the abdomen, hip (septic arthritis, osteomyelitis), spine, etc. The diagnosis is only confirmed using CT scan and/or MRI. In the five patients with antibiotics treatment, the condition resolves without sequelae, even at long-term follow-up.

Surgical aspects of bacterial infection in African children

Infections and their complications requiring surgical intervention are a frequent presentation in African children. Surgical site infection (SSI) is common with rates over 20%, even after clean procedures. The high rates of SSI are due in part to lack of infection control and surveillance policies in most hospitals in Africa. SSI is attended by complications, long hospital stay, and some mortality, but the economic consequences are unestimated. Typhoid fever and typhoid intestinal perforation are major problems with perforation rates of approximately 10%, which is higher in older children. The ideal surgical treatment is arguable, but simple closure and segmental resection are the present effective surgical options. Because of delayed presentation, complications after surgical treatment are high with a mortality approaching 41% in some parts of Africa. Nutrition for these patients remains a challenge. Acute appendicitis, although not as common in African children, often presents rather late with up to 50% of children presenting with perforation and other complications, and mortality is approximately 4% is some settings. Pyomyositis and necrotizing fasciitis are the more common serious soft-tissue infections, but early recognition and prompt treatment should minimize the occasional mortality. Though common in Africa, the exact impact of human immunodeficiency virus infection on the spectrum and severity of surgical infection in African children is not clear, but it may well worsen the course of infection in these patients.

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.

Primary pyomyositis of the paraspinal muscles: a case report and literature review

A case of non-tropical pyomyositis in a healthy, adolescent, 13-year-old boy, affecting the paraspinal muscles is presented. Computerised axial tomography scan (CT scan) of the spine provided valuable information on the nature, extent of the disease and helped to plan successful surgical management. None of the reported cases of such severity of paraspinal pyomyositis had involvement of quadratus lumborum muscle or compression on retroperitoneal organ as in our case.

Primary pyomyositis in children: a retrospective analysis of 11 cases

This study was undertaken to review our approach to diagnosis and treatment in a series of 11 patients (mean age 8.2 years) with primary pyomyositis, who had neither an underlying disease nor a compromised immune system. Nine of the children had positive blood cultures, Staphylococcus aureus (eight) and Streptococcus group A (one). The sites of infection were iliopsoas (four), obturator (two), hip adductors (two), levator scapula (one), thoracolumbar paraspinal (one) and gastrocnemius (one) muscles. Antibiotic treatment was initially intravenous, followed by oral administration. Of five patients with evidence of abscess formation, three underwent percutaneous drainage, whereas two required open surgical drainage. The infection resolved completely without any sequela in 10 children. One patient who developed acute compartment syndrome showed late signs of osteonecrosis of the tibial shaft segment.

Infective Pyomyositis and Myositis in Children in the Era of Community‐Acquired, Methicillin‐ResistantStaphylococcus aureusInfection

BACKGROUND

Cases of pyomyositis and myositis have been increasing in frequency at Texas Children's Hospital (Houston) since 2000. The increase appears to correlate with the emergence of community-acquired methicillin-resistant Staphylococcus aureus (MRSA).

METHODS

The medical records of patients with pyomyositis and myositis hospitalized at Texas Children's Hospital during the period from January 2000 through December 2005 were reviewed. Available S. aureus isolates were obtained for susceptibility testing, to determine the presence of pvl (lukS-PV and lukF-PV), and for pulsed-field gel electrophoresis analysis.

RESULTS

Forty-five previously healthy children with bacterial pyomyositis or myositis were analyzed. The causes were S. aureus (in 57.8% of children) and Streptococcus pyogenes (in 2.2%); 40.0% of children had negative culture results. The number of cases increased between 2000 and 2005, primarily as a result of an increase in the prevalence of community-acquired MRSA. The mean patient age was 5.5 years (range, 0.06-15 years). The thigh (40.0% of children) and pelvis (28.9%) were the most commonly affected sites. The mean abscess diameter was 3.5 cm. Eighteen children required at least 1 muscle drainage procedure. Of the 24 available S. aureus isolates (15 community-acquired MRSA isolates and 9 community-acquired, methicillin-susceptible S. aureus [MSSA] isolates), 16 were found to be USA300 by pulsed-field gel electrophoresis, and 17 carried pvl. Patients with community-acquired MRSA, USA300, and/or pvl-positive strains required more drainage procedures than did those with community-acquired MSSA, non-USA300, and/or pvl-negative strains (81% vs. 40% [P=.05], 82% vs. 29% [P=.02], and 81% vs. 38% [P=.07], respectively).

CONCLUSIONS

Community-acquired MRSA is an increasing cause of pyomyositis and myositis in children. Community-acquired MRSA, USA300, pvl-positive S. aureus isolates caused more severe disease than did community-acquired MSSA, non-USA300, and pvl-negative isolates, respectively.

Musculoskeletal infections in children

Serious musculoskeletal infections in children include osteomyelitis, septic arthritis, pyomyositis, and necrotizing fasciitis. The epidemiology, pathophysiology, and microbiology of each of these infections are reviewed. Specific diagnostic studies and management strategies are discussed. Prompt recognition and treatment is emphasized to prevent potential long-term sequelae.

Pyomyositis in adults: a 12 year review

From January 1988 to December 1999, 43 adults with pyomyositis were managed at Ahmadu Bello UniversityTeaching Hospital, Zaria, Nigeria. Staphylococcus aureuswas the most commonly cultured organism (92.5%). All the 41 patients responded well to incision and adequate drainage, antibiotics and partial thickness skin grafting in 10 patients (23.2%).Two patients (4.65%) died from septicaemia, while being resuscitated.