Tropical pyomyositis: is it an immunodeficiency disease?

Factors associated with pyomyositis: A systematic review and meta-analysis

OBJECTIVES

Pyomyositis, an acute bacterial infection of skeletal muscle usually resulting in abscess formation, is well recognised in tropical regions where it can account for up to 4% of adult surgical admissions. It is increasingly being reported from high-income temperate countries. Pyomyositis occurs across all ages and in both sexes. Mortality ranges from 1% to 23%. Many risk factors have been suggested. We aimed to identify factors associated with pyomyositis.

METHODS

We undertook a systematic review and meta-analysis, using PubMed, EMBASE, Scopus and the Cochran Library and hand-searching published papers. The random-effects model meta-analysis was used to calculate pooled estimated odd ratios with the corresponding 95% confidence interval.

RESULTS

All studies in the systematic review (n = 25) and the meta-analysis (n = 12) were hospital-based. Seven only included children. Relatively few studies have been published in the last decade, the majority of which are from high-income temperate settings. Staphylococcus aureus was the main organism isolated. Males under the age of 20 predominated, and mortality of up to 20% was reported. Factors associated with pyomyositis were HIV infection (OR = 4.82; 95% CI: 1.67-13.92) and fulfilling an AIDS surveillance definition (OR = 6.08; 95% CI: 2.79-13.23).

CONCLUSIONS

Our meta-analysis indicated significant associations between pyomyositis infection and HIV/AIDS. Major gaps in our understanding of the epidemiology, pathogenesis, clinical presentation, and outcome remain, highlighting the need for further research and more systematic studies. Pyomyositis merits consideration as a neglected tropical disease.

Transcriptomics in cancer revealed by Positron Emission Tomography radiomics

Metabolic images from Positron Emission Tomography (PET) are used routinely for diagnosis, follow-up or treatment planning purposes of cancer patients. In this study we aimed at determining if radiomic features extracted from 18F-Fluoro Deoxy Glucose (FDG) PET images could mirror tumor transcriptomics. In this study we analyzed 45 patients with locally advanced head and neck cancer (H&N) that underwent FDG-PET scans at the time of diagnosis and transcriptome analysis using RNAs from both cancer and healthy tissues on microarrays. Association between PET radiomics and transcriptomics was carried out with the Genomica software and a functional annotation was used to associate PET radiomics, gene expression and altered biological pathways. We identified relationships between PET radiomics and genes involved in cell-cycle, disease, DNA repair, extracellular matrix organization, immune system, metabolism or signal transduction pathways, according to the Reactome classification. Our results suggest that these FDG PET radiomic features could be used to infer tissue gene expression and cellular pathway activity in H&N cancers. These observations strengthen the value of radiomics as a promising approach to personalize treatments through targeting tumor-specific molecular processes.

Purulent infectious myositis (formerly tropical pyomyositis)

Purulent infectious myositis (PIM), formerly known as tropical pyomyositis, is a pyogenic infection of skeletal muscles. Staphylococcus aureus, a normal human skin inhabitant, is the main pathogen involved, but multiple other microorganisms have been implicated. Although usually a progressive febrile disease with pain in the affected muscle(s), severe, life-threatening forms have been described, especially in immunosuppressed patients and children. PIM may elude early diagnosis given the lack of overlying skin changes. Hence, high index of suspicion followed by imaging modalities (ultrasonography when superficial and computed tomography or magnetic resonance imaging with contrast when deep) help confirm the diagnosis. Treatment requires combination of percutaneous or open surgical drainage along with antimicrobial therapy guided by culture results. The rising incidence of cases due to methicillin-resistant Staphylococcus aureus (MRSA) strains, makes the inclusion of vancomycin be recommended. This paper reviews PIM highlighting its global distribution, causative agents, predisposing factors, management, and potential complications.

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.

Tropical pyomyositis in children: 10 years experience of a tertiary care hospital in northern India

Tropical pyomyositis (TP) is characterized by suppuration within skeletal muscles, manifesting as single or multiple abscesses. It has been reported frequently from Africa and Latin America. However, there are only a few cases reported in children from India. Between January 2002 and December 2011, 40 children with TP were admitted to our hospital, and their retrospective review formed the study material. TP is not an uncommon disease in children in Northern India, especially during rainy seasons. Most of the patients were admitted with short history of fever, pain and localized swelling. Pus drainage was done in 87.5% cases, with the amount of pus varying from 5 to 2000 ml. The pus grew methicillin-sensitive Staphylococcus aureus (MSSA) in 42.5% cases, whereas initial blood cultures were sterile. All received antibiotics along with surgical drainage, and recovered. It is important for health professionals to have a high index of suspicion and familiarity with this imminently treatable disease entity.

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.

Gluteal pyomyositis in a non-tropical region as a rare cause of sciatic nerve compression: a case report

INTRODUCTION

Pyomyositis, or isolated abscess formation within a skeletal muscle, is a relatively common condition in tropical climates but it is only encountered rarely in temperate zones.

CASE PRESENTATION

We present a case of non-tropical pyomyositis of the gluteal muscle in a 26-year-old, previously healthy man from the United Kingdom, who initially presented with sciatica-like symptoms which began 3 days after a mosquito bite on his nose, which had become infected and discharged pus.

CONCLUSION

Gluteal pyomyositis involving the sciatic nerve may initially present as radiculopathy. Mosquito bites may have been the source of transient bacteraemia that contributed to muscle suppuration in this patient. This may explain, at least in part, the increased incidence of pyomyositis in healthy individuals living in tropical regions.

Tropical pyomyositis in a case of rheumatoid arthritis

Tropical pyomyositis is very rarely associated with rheumatoid arthritis. We report tropical pyomyositis involving gastrocnemius muscle in both the legs with eosinophilia and elevated serum IgG and IgE levels in a case of rheumatoid arthritis. We suggest that the possibility of pyomyositis should be considered in all cases of rheumatoid arthritis presenting with muscle pain, fever and leucocytosis.

Comparison of the clinical and laboratory features of muscle infections caused by Salmonella and those caused by other pathogens

Muscle infections caused by Salmonella constitute an uncommon complication of extraenteric salmonellosis. The aim of this study was to compare the clinical features of Salmonella muscle infections with those reported in several large series of typical, both tropical and non-tropical, pyomyositis, caused mostly by Staphylococcus aureus. A literature survey of Salmonella muscle infections was carried out by using MEDLINE files 1966 through 2000, and cross-references from the selected articles, as well as major reviews of Salmonella infections and of pyomyositis. The survey yielded 32 cases suitable for analysis. The sex distribution, duration of symptom at presentation, degree of fever, involvement of multiple muscle groups, and leukocyte counts were not significantly different between patients with muscle infections caused by Salmonella and typical pyomyositis patients. In contrast, the median age of the patients with Salmonella muscle infections, and the rate of underlying conditions, were significantly higher than those in typical pyomyositis. Psoas muscle was involved more commonly in Salmonella infections than in typical pyomyositis, and the yield of positive blood cultures and, particularly, the mortality rate, were substantially higher in Salmonella muscle infections than in typical pyomyositis. We conclude that patients with Salmonella muscle infections seem to have some different characteristics with respect to typical pyomyositis, such as older age, and higher rates of associated conditions, psoas muscle involvement, bacteremia, and mortality.

Nontropical Pyomyositis: Analysis of Eight Patients in an Urban Center

Nontropical pyomyositis is rare and usually associated with immunodeficiency virus (HIV) infection. This study assessed manifestations and response to treatment of nontropical pyomyositis in an area with a high prevalence of HIV seropositivity. We undertook a chart review of eight consecutive patients treated for pyomyositis—primary infection of skeletal muscles—from 1988 through 1998. All patients complained of myalgia; four (50%) had fever and six (75%) had leukocytosis. Muscles involved were deltoid, quadriceps, gluteus, and psoas. Six (75%) patients had identifiable risk factors for pyomyositis: HIV seropositivity (two), history of intravenous drug abuse (one), chronic paraplegia and malnutrition (one), diabetes and chronic renal failure (one), and leukemia (one). One patient had had streptococcal pharyngitis previously but was otherwise healthy; another, a 2-year-old, had no evidence of underlying disease. Staphylococcus aureus was the most common organism isolated (50%). Four patients were treated with incision and drainage plus antibiotics; the remaining four patients were treated with intravenous antibiotics only; all recovered. Nontropical pyomyositis, which is often associated with HIV seropositivity or chronic illness, has a favorable outcome. Treatment can be effective even without surgical intervention.

[The association between human toxocariasis and pyogenic abscesses]

The association between hepatic abscesses and schistosomiasis mansoni was confirmed by clinical and experimental studies. Other parasites may cause systemic immunologic changes and local structural alterations in the affected organs that can facilitate the seeding of these areas by bacteria. Tropical pyomyositis, pyogenic liver and renal abscesses are frequent diseases in tropical areas. The visceral larva migrans syndrome is caused by the presence, in the human body, of larvae of worms that have other animals as their definitive host, most commonly being caused by Toxocara canis. The larvae migrate to various body organs leading to many inflammatory reactions in the form of granuloma and tissue necrosis. In this review we discuss the possible host-parasite-bacteria interactions that would favour the formation of abscesses in the organs involved by the larva of T. canis and present preliminary results of a clinical and experimental study undertaken during the last four years to define the role of this parasite in the pathogenesis of the abscesses.

Tropical pyomyositis

Tropical pyomyositis (TP), a suppurative disease caused predominantly by Staphylococcus aureus, is responsible for 3% to 4% of surgical admissions in some hospitals in certain tropical countries. This study describes the clinical features of 35 patients with TP (20 males, 15 females; mean +/- SD age 28.3 +/- 14.1 years) admitted to our hospital during a 1-year period and analyzes the causal association between ancylostomiasis, human immunodeficiency virus (HIV) infection, and TP. Concerning the supposed etiologic association between Ancylostoma duodenale infection and TP, among the 35 patients with TP the stool examination of 22 (62.8%) revealed the presence of eggs of A. duodenale. In a control group of 100 asymptomatic subjects the prevalence of ancylostomiasis was 55%. The Odds ration between the two groups is 1.38 (exact 95% confidence limits = 0.59 < OR < 3.34). Furthermore, the pus from all TP abscesses (41 in 35 patients) was carefully collected and examined microscopically, but nematode larvae were not detected in any of the specimens. Hence these results do not support an association between ancylostomiasis and TP. With the aim of correlating TP with HIV infection, I carried out a case-control comparison of HIV seroprevalence among the patients affected by TP and an age- and sex-matched control group of healthy subjects. Eleven patients with TP were HIV antibody-positive (seroprevalence 31.42%), as were two controls (seroprevalence 5.71%). The matched analysis produced a Mantel-Haenszel matched Odds ratio of 5.50 and a maximum likelihood estimate of OR (MLE) of 5.50 (exact 95% confidence limits for MLE: 1.20 < OR < 51.07). Among the 11 patients HIV-seropositive, 9 (81.8%) fulfilled the World Health Organization clinical case definition (CCD) for AIDS, compared with 1 of 24 (4.1%) HIV-negative subjects. The chi-square test for difference in fulfilling the CCD for AIDS between patients with TP seropositive and seronegative result was statistically significant (p < 0.0001). It is concluded that TP is a bacterial infection highly significantly associated with HIV infection and thus must be considered a strong sign of stage III-IV of HIV disease.

High HIV seroprevalence among patients with pyomyositis in northern Uganda

With the aim of correlating pyomyositis with HIV infection, we have carried out a case-control comparison of HIV seroprevalence among patients affected by pyomyositis and an age and sex-matched control group of healthy subjects. Over a one-year period, 35 patients with pyomyositis, 20 male and 15 female, mean age 28.31 years, were admitted to Dr Ambrosoli Memorial Hospital of Kalongo (Kitgum District, Northern Uganda). Among these patients, II were HIV-antibody-positive, with a seroprevalence of 31.42%. In the age and sex-matched control group of 35 healthy subjects, selected in the same period from volunteers admitted to the surgical ward for orthopaedic trauma, two were HIV-antibody-positive, with a seroprevalence of 5.71%. The matched analysis produced a Mantel-Haenszel matched odds ratio of 5.50 and a maximum likelihood estimate of OR (MLE) of 5.50 (exact 95% confidence limits for MLE = 1.20 < OR < 51.07). Among the II HIV-seropositive patients, 9 (81.8%) fulfilled the World Health Organization (WHO) clinical case definition (CCD) for AIDS, compared with I of twenty-four (4.1%) HIV-negatives. The chi-square test for difference in fulfilling the CCD for AIDS between patients with pyomyositis seropositive and seronegative gave a statistically significant result (P < 0.0001). The authors conclude that pyomyositis is a bacterial infection very significantly associated with HIV infection, to be considered a strong sign of stage III-IV of HIV disease.

Bacterial infections: pyomyositis

Staphylococcal pyomyositis is an important and common condition in many areas in the tropics. The cause is probably multifactorial and includes damage to the skeletal muscle in the presence of staphylococcal bacteraemia, with or without depressed immunity. In Africa, there are indications of an increased prevalence in association with HIV infection in young adults in whom multiple and recurrent abscesses are common. Long bone osteomyelitis is an important differential diagnosis in these patients. Timely surgical drainage and antibiotics leads to resolution. Delayed diagnosis is associated with disseminated disease and septic cardiorespiratory complications.

Nontropical pyomyositis in adults

Pyomyositis (PMS) is a primary infection of striated muscle. Recent scanty reports suggest that non-tropical PMS may differ from classical tropical PMS. To address this question, 12 cases of nontropical PMS seen at two hospitals between 1976 and 1992 were reviewed and an English-literature search of similar cases was conducted. Both the series and reported cases are pooled together and herein reported. The age distribution of the 97 patients showed 30-50 and 60-70-year peaks, with a 3:1 (male-female) ratio. Fever, high erythrocyte sedimentation rate, and muscle stiffness or inflammation were present in more than 75% of patients. Muscles of the thigh (54%), back (13%), buttock (11%), arm (9%), or chest wall (4%) were involved. Staphylococci (61%), gram-negative bacilli (16%), streptococci (12%), and fungi (2%) were isolated from muscle specimens. Human immunodeficiency virus infection, diabetes mellitus, hemopoietic disorders, and other conditions with defective neutrophil function were present in 64 patients (66%). Drainage of pus and antibiotic therapy were the standard treatments. The mortality rate reached 10%. Analysis of patients classified by the comorbid condition showed differences in age, causative microorganisms, clinical features, and death rate. It is concluded that several clinical presentations of nontropical PMS are at variance with that of tropical PMS.

Pyomyositis and staphylococcal scalded skin syndrome

Pyomyositis is a rare musculoskeletal infection in non-tropical countries. We report a child who had pyomyositis complicated by staphylococcal scalded skin syndrome. This complication has not previously been described in patients with pyomyositis. Early diagnosis of pyomyositis was made by ultrasound examination, and percutaneous needle drainage under ultrasound guidance was performed. Pus aspirated and blood cultures grew Staphylococcus aureus. No open surgical drainage was required and resolution of the abscess was documented by serial ultrasound examinations.

Pyomyositis in patients with the human immunodeficiency virus: an unusual form of disseminated bacterial infection

PURPOSE AND PATIENTS

Pyomyositis, a common disease in the tropics, is rare in the continental United States, with approximately 83 cases described in the literature in the past two decades. The occurrence of pyomyositis complicating human immunodeficiency virus (HIV) infection has been reported in 10 patients since 1986. We report six cases of this entity in patients with advanced HIV disease seen in our institution over a 20-month period. A common denominator in all of our patients was muscle injury, induced by either exercise or trauma. Unlike most previous reports of HIV-associated pyomyositis, the clinical picture in our cases was complicated by the development of abscesses in multiple muscle groups, requiring prolonged antimicrobial therapy and repeated drainage procedures for successful management. Interestingly, one patient developed concomitant rhabdomyolysis--an otherwise rare event in classical pyomyositis. Staphylococcus aureus was the predominant infecting organism in this as well as all other series. Of note, we also observed and report the first case, to our knowledge, of gram-negative pyomyositis in an HIV-infected individual. The pathogenic implications of this catalase-producing gram-negative isolate are discussed in the context of neutrophil abnormalities in HIV disease.

CONCLUSION

Like tropical pyomyositis, its HIV-associated counterpart appears to be multifactorial in origin. Its recent recognition suggests that, in addition to underlying abnormalities of host defense, factors relating to the prolonged survival of patients with late-stage disease, including myopathy, might play an important contributory role.

Tropical pyomyositis associated with Trypanosoma brucei rhodesiense infection in a Europid

A 29-year-old European woman became infected with Trypanosoma brucei rhodesiense in the Luangwa valley, Zambia. Six days after the initial presentation of this infection she developed evidence of tropical pyomyositis (TP). These diseases, both of which are rare in Europids, were satisfactorily treated. The pathogenesis of TP, which is nearly always caused by Staphylococcus aureus, is undetermined. It seems possible that in this case either (i) both infections were introduced simultaneously by a tsetse-fly bite, or (ii) T. b. rhodesiense produced multiple focal necroses in skeletal muscles which acted as niduses for the staphylococcal infections; immunodepression caused by this parasite might also have been important.