Clinical features and outcome of septic arthritis in a single UK Health District 1982-1991

Comparison of synovial fluid culture and 16S rRNA PCR in dogs with suspected septic arthritis

OBJECTIVE

To prospectively compare the sensitivity and specificity of 16S rRNA PCR with culture for identifying the causative organism in synovial fluid obtained from dogs with suspected septic arthritis.

METHODS

Synovial fluid cytology, PCR analysis and aerobic, anaerobic and Mycoplasma culture of samples from the affected joints of 18 dogs presenting with suspected septic arthritis were performed. Synovial fluid samples from the corresponding contralateral joints of 7 dogs were also analysed as negative controls.

RESULTS

There was no significant difference between the sensitivity of bacterial detection via culture (63.2%) versus PCR (73.7%) of synovial fluid (P=0.728) or between culture and combined PCR and culture (89.5%) of synovial fluid (P=0.124). The specificity of PCR (42.9%) was significantly lower than culture specificity (100%) (P=0.07).

CONCLUSION

Although 16S PCR may hold potential as an ancillary diagnostic test for identifying the causative organism in dogs with septic arthritis, our study failed to demonstrate improved accuracy compared with traditional synovial fluid culture.

MALDI-TOF MS performance compared to direct examination, culture, and 16S rDNA PCR for the rapid diagnosis of bone and joint infections

The rapid identification of bacterial species involved in bone and joint infections (BJI) is an important element to optimize the diagnosis and care of patients. The aim of this study was to evaluate the usefulness of matrix-assisted laser desorption ionization mass spectrometry (MALDI-TOF MS) for the rapid diagnosis of bone infections, directly on synovial fluid (SF) or on crushed osteoarticular samples (CS). From January to October 2013, we prospectively analyzed 111 osteoarticular samples (bone and joint samples, BJS) from 78 patients in care at the University Hospital of Rennes, France. The diagnosis procedure leading to the sample collection was linked to a suspicion of infection, inflammatory disease, arthritis, or for any bone or joint abnormalities. Standard bacteriological diagnosis and molecular biology analysis [16S rRNA polymerase chain reaction (PCR) and sequencing] were conducted. In addition, analysis by MALDI-TOF MS was performed directly on the osteoarticular samples, as soon as the amount allowed. Culture, which remains the gold standard for the diagnosis of BJI, has the highest sensitivity (85.9 %) and remains necessary to test antimicrobial susceptibility. The 16S rDNA PCR results were positive in the group with positive BJI (28.6 %) and negative in the group without infection. Direct examination remains insensitive (31.7 %) but more effective than MALDI-TOF MS directly on the sample (6.3 %). The specificity was 100 % in all cases, except for culture (74.5 %). Bacterial culture remains the gold standard, especially enrichment in blood bottles. Direct analysis of bone samples with MALDI-TOF MS is not useful, possibly due to the low inoculum of BJS.

Staphylococcus aureus-Associated Musculoskeletal Infections

Musculoskeletal infections caused by Staphylococcus aureus are among the most difficult-to-treat infections. S. aureus osteomyelitis is associated with a tremendous disease burden through potential for long-term relapses and functional deficits. Although considerable advances have been achieved in diagnosis and treatment of osteomyelitis, the management remains challenging and impact on quality of life is still enormous. S. aureus acute arthritis is relatively seldom in general population, but the incidence is considerably higher in patients with predisposing conditions, particularly those with rheumatoid arthritis. Rapidly destructive course with high mortality and disability rates makes urgent diagnosis and treatment of acute arthritis essential. S. aureus pyomyositis is a common disease in tropical countries, but it is very seldom in temperate regions. Nevertheless, the cases have been increasingly reported also in non-tropical countries, and the physicians should be able to timely recognize this uncommon condition and initiate appropriate treatment. The optimal management of S. aureus-associated musculoskeletal infections requires a strong interdisciplinary collaboration between all involved specialists.

Native Joint Septic Arthritis: Epidemiology, Clinical Features, and Microbiological Causes in a New Zealand Population

Objective.

To determine the epidemiology, clinical features, and microbiology of adult native joint septic arthritis in Canterbury, New Zealand, over a 5-year period in individuals with and without an underlying rheumatic disorder.

Methods.

Patients with native joint septic arthritis were identified retrospectively and classified by Newman’s criteria. The clinical characteristics were described and comparisons made between those with and without underlying rheumatic disease.

Results.

Two hundred forty-eight cases of native joint septic arthritis (mean age 60, range 16–97 yrs) were identified with an overall incidence rate of 12.0/100,000/year (95% CI 10.6–13.6). Yearly incidence increased with age to a maximum of 73.4/100,000 in those > 90 years of age. Septic arthritis was iatrogenic in 16.9% of cases while 27% had an underlying inflammatory arthritis including gout (14.9%), calcium pyrophosphate disease (8.5%), and rheumatoid arthritis (4%). Few patients were taking immunosuppressant therapy, with just 1 taking a biological agent. Staphylococcus aureus was the most commonly identified organism. Those with underlying inflammatory arthritis were significantly older (73.6 yrs vs 55.6 yrs; p < 0.001), more likely to be female (55.2% vs 26.0%; p < 0.001), and to have septic polyarthritis (16.4% vs 4.4%; p = 0.002). The 30-day mortality was 2%, increasing to 6% at 90 days.

Conclusion.

The incidence of septic arthritis in Canterbury, New Zealand, is higher than in previous studies. Crystal arthropathy commonly coexisted with infection although autoimmune arthritis and immunosuppression was less of a factor than anticipated.

Clinical manifestations and bacteriological features of culture-proven Gram-negative bacterial arthritis

BACKGROUND/PURPOSE

To investigate the clinical manifestations and bacteriological features of culture-proven, Gram-negative bacterial arthritis.

METHODS

This study was conducted at the Chi Mei Medical Center, a 1300-bed teaching hospital located in southern Taiwan. Patients with synovial fluid cultures positive for Gram-negative bacilli (GNB) during the period January 2009 to May 2014 were identified from the hospital's computerized microbiology database.

RESULTS

During the study period, a total of 48 patients with culture-confirmed, GNB septic arthritis were identified. In the majority of patients (n = 33, 68.8%), the knee was the most commonly involved joint. The most common causative pathogen was Pseudomonas spp. (n = 16, 33.3%), followed by Escherichia coli (n = 13, 28.1%). Among the 29 clinical isolates of Enterobacteriaceae, eight (27.6%) were resistant to ceftriaxone and six (20.7%) were resistant to cefpirome. Three E. coli isolates and three Klebsiella pneumoniae isolates were extended-spectrum beta-lactamase producers (n = 6, 20.7%). Among the nonfermenting GNB (NFGNB), 21.1% were resistant to ceftazidime, 21.1% were resistant to ciprofloxacin, 26.3% were resistant to piperacillin-tazobactam, and 15.8% were resistant to imipenem. The overall mortality rate was 10.4%, and the significant risk factors for death were concomitant bacteremia [odds ratio (OR): 14.6, 95% confidence interval (CI): 1.9-115.2, p = 0.011] and liver cirrhosis (OR: 20.0, 95% CI: 2.4-169.9, p = 0.006).

CONCLUSION

Approximately 25% of cases of septic arthritis were due to GNB and resistance to commonly used antimicrobial agents was common. Liver cirrhosis and concomitant bacteremia were significant risk factors for death.

A systematic review and meta-analysis regarding the use of corticosteroids in septic arthritis

Background

Chondral damage is one of the major sequelae of septic arthritis; occurring even after prompt treatment of a septic joint. Subsequent loss of joint function can have a significant impact on a patient’s quality of life. Corticosteroids are known to have beneficial effects on the rate and extent cartilage destruction in arthritis through a variety of mediators such as synovial RANKL expression, mast cells and pro-inflammatory cytokines. Investigation into sepsis at other sites has suggested improved outcomes with corticosteroid use despite the theoretical risks. This study therefore set out to review current literature with regards to a possible beneficial effect for corticosteroids in Septic Arthritis.

Methods

A computerised search of the databases MEDLINE and CINAHL was conducted during November 2014 using the EBSCOhost web search engine in order to identify research articles relating to the use of corticosteroids in the treatment of septic arthritis. The search strategy revealed 223 unique articles which were subjected to inclusion/exclusion criteria assessment. 6 articles were selected for study inclusion. These consisted of 3 human studies (2 double-blind randomised controlled trials & 1 double-blind non-randomised controlled trial), and 3 animal studies (3 non-blinded non-randomised controlled trials). Quantitative synthesis (meta-analysis) was only possible regarding two primary outcomes for two of the included studies – time to normalisation of CRP and duration of IV antibiotic therapy.

Results

All current published evidence in humans is focused upon children. Overall results did however reveal a consensus between these studies for a reduced duration of symptoms and a reduction in inflammatory markers. Animal data suggested a protective effect on the articular cartilage with the addition of corticosteroids to antibiotic therapy. No article noted an adverse effect associated with steroid use. Findings were consistent with systematic reviews of corticosteroid use in other bacterial infections.

Conclusions

Despite the promising outlook, issues’ regarding generalisability of results and a lack of large randomised controlled trial data necessitates further assessment of the safety and efficacy of steroid use in adults before treatment recommendations can be made. Long term safety data and the determinations of the optimum route, dose and timing of corticosteroids are also required.

Utilization of Hyaluronate and Incidence of Septic Knee Arthritis in Adults: Results from the Korean National Claim Registry

Background

Septic arthritis of the knee has been reported recently in adult patients who were administered hyaluronate. We evaluated the incidence of septic knees and the utilization of hyaluronate in the Korean adult population using nationwide data from the Health Insurance Review and Assessment Service (HIRA).

Methods

All new admissions to the clinics or hospitals for septic knees were recorded in the HIRA database which was established by the Korean government and covers the Korean population using the International Classification of Diseases-10 revision code. We evaluated the incidence of septic arthritis of the knees in the population above 50 years of age. Hyaluronate prescription data was also collected from the HIRA database.

Results

In 2012, the incidence of septic knees was 2.7 per 100,000 persons in men and 4.2 per 100,000 persons in women, respectively. The age-adjusted incidence of septic knees increased by 6.7% per year (95% confidence interval, 3.3 to 10.1), and the annual number of prescriptions of hyaluronate increased about 1.5-fold during the study period.

Conclusions

Cautious aseptic technique is required when hyaluronate is administered in adult patients with osteoarthritis of the knee due to the concerns of the risk of septic arthritis.

An Unusual Cause of Chest Pain in a Young Healthy Female

BACKGROUND

Infection of the sternoclavicular joint is an uncommon disease that is usually seen in patients with underlying risk factors such as prior trauma, intravenous drug use, or diabetes mellitus. The true pathophysiology remains unknown, but underlying bacteremia has been found in a number of cases. Without proper diagnosis and treatment, severe complications such as mediastinitis, sepsis, or death can occur.

CASE REPORT

This is a case of spontaneous stenoclavicular septic arthritis in an otherwise healthy female. The patient's lack of risk factors and minimal examination findings highlight the unusual nature of the case, as well as the challenges it presents in making an early diagnosis. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS CONDITION?: Emergency physicians should consider sternoclavicular joint infections in patients who present to the emergency department with chest pain, even in patients without risk factors. They should especially consider the diagnosis in patients with suspected musculoskeletal etiologies or in those with return visits for chest pain. Although most patients do well with treatment, the infection can be life threatening without appropriate interventions.

Macrophage activation syndrome or septic arthritis: a case of mistaken identity

We present an interesting case of macrophage activation syndrome in a 2-year-old, with no previous rheumatological diagnoses, incorrectly diagnosed with septic arthritis, to highlight the diagnostic difficulties, especially in small hospital units. We aim to present the similarities between the two conditions and to summarize the clinical, radiological and epidemiological features of macrophage activation syndrome, an underdiagnosed condition. A review of the current literature was performed, and a diagnostic algorithm was created. No current set treatment regimen exists, but current recommendations have been included. We have demonstrated the pitfalls in diagnosis and the importance of immediate treatment in optimizing prognosis.

Staphylococcus aureus infections: epidemiology, pathophysiology, clinical manifestations, and management

Staphylococcus aureus is a major human pathogen that causes a wide range of clinical infections. It is a leading cause of bacteremia and infective endocarditis as well as osteoarticular, skin and soft tissue, pleuropulmonary, and device-related infections. This review comprehensively covers the epidemiology, pathophysiology, clinical manifestations, and management of each of these clinical entities. The past 2 decades have witnessed two clear shifts in the epidemiology of S. aureus infections: first, a growing number of health care-associated infections, particularly seen in infective endocarditis and prosthetic device infections, and second, an epidemic of community-associated skin and soft tissue infections driven by strains with certain virulence factors and resistance to β-lactam antibiotics. In reviewing the literature to support management strategies for these clinical manifestations, we also highlight the paucity of high-quality evidence for many key clinical questions.

Infections and arthritis

Bacteria, viruses, fungi, and parasites can all cause arthritis of either acute or chronic nature, which can be divided into infective/septic, reactive, or inflammatory. Considerable advances have occurred in diagnostic techniques in the recent decades resulting in better treatment outcomes in patients with infective arthritis. Detection of emerging arthritogenic viruses has changed the epidemiology of infection-related arthritis. The role of viruses in the pathogenesis of chronic inflammatory arthritides such as rheumatoid arthritis is increasingly being recognized. We discuss the various causative agents of infective arthritis and emphasize on the approach to each type of arthritis, highlighting the diagnostic tests, along with their statistical accuracy. Various investigations including newer methods such as nucleic acid amplification using polymerase chain reaction are discussed along with the pitfalls in interpreting the tests.

[Septic arthritis in adults]

Septic arthritis is a true rheumatological emergency requiring immediate and thoughtful effort for rapid diagnosis establishment and treatment initiation. Children and elderly persons as well as immunocompromised individuals, patients with pre-existing joint damage and with inflammatory rheumatic joint diseases are preferentially affected. Bacteremia, joint surgery and intra-articular injections pose risk situations for the development of joint infections. The most frequent causative organism is Staphylococcus aureus but other relevant pathogens include coagulase-negative staphylococci, streptococci and mycobacteria. Synovial fluid analysis (e.g. appearance, cell count and microbiological examination) is the most important step to establish the diagnosis. The two main components of therapy consist of joint drainage and antibiotic treatment. The approach to periprosthetic joint infections depends on the duration of symptoms, causative organism and individual factors.

Poor adherence to guidelines on early management of acute hot swollen joint(s): an evaluation of clinical practice and implications for training

BACKGROUND

Synovial fluid analysis is an indispensable investigation to attain a diagnosis in a patient with acute hot swollen joint(s), septic arthritis in particular. A delay in appropriate early management results in serious undesired consequences.

METHODS

We evaluated clinical practice at two teaching hospitals including 81 patients. We analysed medical records, laboratory pathology results and discharge summaries with regard to documentation of joint aspiration, blood cultures, antibiotic treatment and specialist referral. We then conducted a survey of 140 medical trainees to evaluate their self-reported competence at managing the acute hot swollen joint.

RESULTS

We found that synovial aspiration and blood cultures were performed in only 42(52%) and 30(37%) patients, respectively, not in accord with current guidelines. Given trainee doctors are responsible for the early management of acute hot swollen joint(s), our survey reveal low self-reported levels of competence and confidence at managing acute hot swollen joint(s) in 72(52%) and 37(27%) respondents, respectively. Furthermore, 101(75%) trainees indicated a need for more training in joint aspiration. We also report that 13 of 15 hospitals surveyed in London and South East UK do not provide specific training on the management of the hot swollen joint and joint aspiration as part of their induction programme.

CONCLUSIONS

Early management of patients with hot swollen joint(s) to perform synovial fluid aspiration and blood cultures are not being done in accordance with guidelines. We suggest that the medical trainee curricula should incorporate joint aspiration skills as an 'essential procedure', to improve the trainee doctor's confidence and competence at managing acute hot swollen joint(s) to improve adherence to guidelines, and consequently, patient outcomes.

Arthritis, Infectious Tenosynovitis, and Tendon Rupture in a Patient With Rheumatoid Arthritis and Psoriasis

Multiple comorbidities, advanced age, tobacco use, and alcohol abuse made a proper diagnosis difficult in a patient with polyarticular septic arthritis, infectious tenosynovitis, and ruptures in the tendons of both thumbs.

Clinical and epidemiological differences between septic arthritis of the knee and hip caused by oxacillin-sensitive and -resistant s. aureus

OBJECTIVE

To establish the risk factors for joint infection by oxacillin-resistant Staphylococcus aureus (MRSA) using clinical and epidemiological data.

METHODS

All septic arthritis cases of the knee and hip diagnosed and treated in our institution from 2006 to 2012 were evaluated retrospectively. Only patients with cultures identified as microbial agents were included in the study. The clinical and epidemiological characteristics of the patients were analyzed, seeking the differences between populations affected by MRSA and oxacillin-sensitive Staphylococcus aureus (MSSA).

RESULTS

S. aureus was isolated in thirty-five patients (46.0%) in our total sample, 25 in the knee and 10 in the hip. Of these 35 patients, 22 presented with MSSA and 13 presented with MRSA. Provenance from a health service-related environment, as described by the Centers for Disease Control and Prevention, was the only variable associated with oxacillin-resistant strains of this bacterium (p = 0.001).

CONCLUSION

Provenance from a health service-related environment was associated with a higher incidence of MRSA-related septic arthritis, suggesting that this agent should be considered in the initial choice of antibiotic treatment. Previous surgeries of the knee or affected limb and the absence of leukocytes might also be related to infection with this agent.

Predictors of treatment failure and mortality in native septic arthritis

The aims of this study are to analyse the characteristics of septic arthritis stratified by age and to identify the predictors of treatment failure and mortality in septic arthritis. A retrospective single-centre study was conducted in patients with native septic arthritis between 1994 and 2012. The primary outcome was treatment failure. Secondary outcomes included mortality, complications, endocarditis, bacteraemia, hospital readmission and the duration of the hospital stay. Logistic regression analyses with a propensity score were performed to identify the predictors of response and mortality. Additional analyses were performed according to age and the initial treatment (surgery or conservative). A total of 186 patients were studied. The median (interquartile range) age was 64 (46, 74) years, and the percentage of male patients was 68.9%. A logistic regression analysis showed that Staphylococcus aureus infection [OR 2.39 (1.20-4.77), p = 0.013], endocarditis [OR 4.74 (1.16-19.24), p = 0.029] and the involvement of joints difficult to access with needle drainage [OR 2.33 (1.06-5.11), p = 0.034] predict treatment failure and that age [OR 1.27 (1.07 = 1.50), p = 0.005], the leucocyte count at baseline [OR 1.01 (1.00-1.02), p = 0.023], bacteraemia [OR 27.66 (1.39-551.20), p = 0.030], diabetes mellitus [OR 15.33 (1.36-172.67), p = 0.027] and chronic renal failure [OR 81.27 (3.32-1990.20), p = 0.007] predict mortality. No significant differences in treatment failure by age were found. In septic arthritis, the predictors of mortality and the predictors of treatment failure differ. The predictors of treatment failure concern local factors and systemic complications, whereas conditions related to the host's immune competence, such as age and comorbidities that hamper the host's response, predict mortality.

Streptococcus pyogenes sternoclavicular septic arthritis in a healthy adult

Sternoclavicular septic arthritis is a rare infection, accounting for approximately 1% of septic arthritis in the general population. Staphylococcus aureus is the predominant etiologic agent, and it usually occurs in relatively young adults with some type of predisposition to infection. We report, to the best of our knowledge, the first case of group A streptococcal, sternoclavicular arthritis in a previously healthy 62-year-old male patient. We present a detailed history and physical examination, with laboratory findings, imaging studies, cultures, and therapy.

Determinants of methicillin-susceptible Staphylococcus aureus native bone and joint infection treatment failure: a retrospective cohort study

Background

Although methicillin-susceptible Staphylococcus aureus (MSSA) native bone and joint infection (BJI) constitutes the more frequent clinical entity of BJI, prognostic studies mostly focused on methicillin-resistant S. aureus prosthetic joint infection. We aimed to assess the determinants of native MSSA BJI outcomes.

Methods

Retrospective cohort study (2001–2011) of patients admitted in a reference hospital centre for native MSSA BJI. Treatment failure determinants were assessed using Kaplan-Meier curves and binary logistic regression.

Results

Sixty-six patients (42 males [63.6%]; median age 61.2 years; interquartile range [IQR] 45.9–71.9) presented an acute (n = 38; 57.6%) or chronic (n = 28; 42.4%) native MSSA arthritis (n = 15; 22.7%), osteomyelitis (n = 19; 28.8%) or spondylodiscitis (n = 32; 48.5%), considered as “difficult-to-treat” in 61 cases (92.4%). All received a prolonged (27.1 weeks; IQR, 16.9–36.1) combined antimicrobial therapy, after surgical management in 37 cases (56.1%). Sixteen treatment failures (24.2%) were observed during a median follow-up period of 63.3 weeks (IQR, 44.7–103.1), including 13 persisting infections, 1 relapse after treatment disruption, and 2 super-infections. Independent determinants of treatment failure were the existence of a sinus tract (odds ratio [OR], 5.300; 95% confidence interval [CI], 1.166–24.103) and a prolonged delay to infectious disease specialist referral (OR, 1.134; 95% CI 1.013–1.271).

Conclusions

The important treatment failure rate pinpointed the difficulty of cure encountered in complicated native MSSA BJI. An early infectious disease specialist referral is essential, especially in debilitated patients or in presence of sinus tract.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2334-14-443) contains supplementary material, which is available to authorized users.

Clinical guidelines for the antimicrobial treatment of bone and joint infections in Korea

There are many various diseases in the bone and joint infections, and we tried to make antimicrobial treatment guidelines for common infectious diseases based on available data for microbiology and clinical trials. This guidelines focused on the treatment of osteomyelitis and septic arthritis, which can be experienced by physicians at diverse clinical settings. This guidelines is not applicable to diabetic foot infections, postoperative infections or post-traumatic infections which need special considerations. The guidelines for those conditions will be separately developed later. Surgical treatment of bone and joint infections, pediatric bone and joint infection, tuberculous bone and joint infection, and prophylactic antibiotic use were not included in this guideline.

Clinical results after arthroscopic treatment for septic arthritis of the elbow joint

PURPOSE

The purpose of this study was to examine clinical findings of septic arthritis of the elbow joint in a series of immunocompetent patients and to evaluate the outcomes after arthroscopic treatment.

METHODS

Between October 2006 and January 2012, 11 patients with septic arthritis of the elbow underwent arthroscopic surgery. History, laboratory findings, and radiologic findings were reviewed. Functional outcomes were evaluated using the Mayo Elbow Performance Score (MEPS).

RESULTS

The study included 5 men and 6 women with a mean age of 45 years. An underlying medical disease was present in 1 patient (diabetes). Staphylococcus aureus was the most common organism identified (5 patients). There was 1 reoperation and no complications related to the arthroscopic procedure. Eight of 11 patients had excellent results assessed by MEPS at the final follow-up. The mean MEPS was 94.5 at the final follow-up.

CONCLUSIONS

Septic arthritis of the elbow joint can occur in otherwise healthy patients without pre-existing elbow disease. Arthroscopic irrigation and synovectomy are safe and effective in patients with septic arthritis and result in good functional outcomes.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Septic arthritis: immunopathogenesis, experimental models and therapy

Septic arthritis is an inflammatory disease of the joints that is started by an infection whose most common agent is Staphylococcus aureus. In this review we discuss some of the most arthritogenic bacterial factors and the contribution of innate and specific immune mechanisms to joint destruction. Special emphasis is given to the induction of experimental arthritis by S. aureus in mice. The improvement of therapy by association of antibiotics with down-modulation of immunity is also included.

False-negative rate of gram-stain microscopy for diagnosis of septic arthritis: suggestions for improvement

We quantify the false-negative diagnostic rate of septic arthritis using Gram-stain microscopy of synovial fluid and compare this to values reported in the peer-reviewed literature. We propose a method of improving the diagnostic value of Gram-stain microscopy using Lithium Heparin containers that prevent synovial fluid coagulation. Retrospective study of the Manchester Royal Infirmary microbiology database of patients undergoing synovial fluid Gram-stain and culture between December 2003 and March 2012 was undertaken. The initial cohort of 1896 synovial fluid analyses for suspected septic arthritis was reduced to 143 after exclusion criteria were applied. Analysis of our Gram-stain microscopy yielded 111 false-negative results from a cohort size of 143 positive synovial fluid cultures, giving a false-negative rate of 78%. We report a false-negative rate of Gram-stain microscopy for septic arthritis of 78%. Clinicians should therefore avoid the investigation until a statistically significant data set confirms its efficacy. The investigation's value could be improved by using Lithium Heparin containers to collect homogenous synovial fluid samples. Ongoing research aims to establish how much this could reduce the false-negative rate.

Indicators for detection of septic arthritis in the acutely swollen joint cohort of those without joint prostheses

Differentiating septic arthritis from culture-negative, acute atraumatic joint effusion is difficult. Studies have attempted to elucidate factors that herald infection, but, due to overlap, most conclude that the diagnosis ultimately relies on clinical judgment. Furthermore, studies are limited by broad inclusion criteria. The current retrospective case study sought to examine (1) which markers differentiate a culture-positive septic joint from culture-negative effusion in patients suspicious for infection despite no growth on Gram stain and without previous surgery in the affected joint and (2) whether threshold values of these markers exist that predict septic arthritis. The study was performed by reviewing records of those who underwent operative irrigation and debridement involving the shoulder, elbow, wrist, hip, knee, and ankle. Patients were included if they were older than 18 years and had an acutely swollen/painful joint and no organisms on initial Gram stain. Exclusion criteria were lack of serum markers or synovial fluid aspirate, antibiotics within 1 week, adjacent wound or skin infection, recent trauma to the joint, and previous joint infection or surgery to the joint. Several clinical, serological, and synovial parameters were collected and analyzed using paired t test with Bonferonni correction. Serum C-reactive protein was the only significantly different variable between groups. Serum C-reactive protein greater than 10.5 mg/dL was predictive of infection. In those suspicious for infection despite no growth on Gram stain and without previous surgery in the affected joint, C-reactive protein greater than 10.5 mg/dL is suspicious for joint sepsis and should warrant consideration for urgent irrigation and debridement.

Pneumococcal septic arthritis in adults: clinical analysis and review

BACKGROUND

Septic arthritis (SA) is a rheumatological emergency that can lead to rapid joint destruction and irreversible loss of function. The most common pathogen causing SA is Staphylococcus aureus which is responsible for 37-65% of cases. Streptococcus pneumoniae is traditionally described as an uncommon cause of SA of a native joint. The objective of our study was to analyse clinical characteristics, treatment, and outcome of all cases of pneumococcal septic arthritis treated in our institution, and to compare them with other series published in the literature.

MATERIALS AND METHODS

We conducted a retrospective study of pneumococcal SA identified among all cases of SA diagnosed in a teaching hospital of one thousand beds between 2004 and 2009. Diagnosis was based on culture of joint liquid or by the presence of pneumococcal bacteraemia and purulent (more than 50 000/mm(3) white blood cells with more than 90% neutrophils) joint fluid aspiration.

RESULTS

Among 266 cases of SA, nine patients (3·3%) were diagnosed as having pneumococcal SA. The median age was 75 years. The main affected joint was the knee (7/9). No patient had more than one joint involved. Four patients suffered from concomitant pneumonia. Joint culture and blood cultures were positive in 7/9 and 5/9, respectively. Median (range) length of stay was 18 days (3-47 days). One patient with associated pneumococcal bacteraemia died 19 days after admission. Seven patients recovered completely.

CONCLUSIONS

Streptococcus pneumoniae is now being increasingly recognized as a common agent of SA. This organism is frequently associated with pneumococcal pneumonia or bacteraemia, particularly in patients with advanced age and comorbidities. Direct inoculation of joint fluid into blood culture medium BACTEC system increases the probability of microbiological diagnosis. The prognosis is usually favourable if the disease is promptly recognized and treated (antibiotic therapy combined with joint drainage).

Arthroscopic synovectomy, irrigation, and debridement for treatment of septic ankle arthrosis: a systematic review and case series

Septic arthrosis of the ankle is a rare, often devastating, infection, with a high potential for morbidity and mortality. Delay in treatment can lead to cartilage erosion, painful synovitis, and osteomyelitis. Septic ankle arthrosis deserves prompt recognition and intervention. However, quality, sound, protocol-directed arthroscopic treatment of septic ankle arthrosis of the ankle has not yet been reported. We performed a systematic review of the electronic databases and other relevant peer-reviewed sources to determine the outcomes and treatment protocols associated with septic ankle arthrosis treated with arthroscopic synovectomy, irrigation, and debridement. Nine studies, involving a total of 15 ankles, met our inclusion criteria. In addition, we present the short-term outcomes of a protocol-driven arthroscopic synovial biopsy, deep culture procurement, synovectomy, irrigation, and debridement approach for 8 ankles (8 patients). To our knowledge, this would be the largest individual case series specific to arthroscopic treatment of septic ankle arthrosis. The most common infectious organism reported in the systematic review and in our case series was methicillin-sensitive Staphylococcus aureus. Arthroscopic synovectomy, irrigation, and debridement represents an acceptable treatment method for septic ankle arthrosis and demonstrated outcomes similar to the more traditional open approach, with fewer complications. Additional, appropriately weighted, randomized controlled studies with long-term follow-up are warranted.

Septic arthritis: patients with or without isolated infectious agents have similar characteristics

PURPOSE

Septic arthritis can be disabling and life-threatening, requiring prompt diagnosis and treatment. The infectious agent is not always identified in these patients. We revaluate septic arthritis cases discharged from our department, describing the affected population, causative microorganisms and antibiotic therapy used, and characterised differences between patients with and without isolated pathogenic agents.

METHODS

Sixty-eight septic arthritis patients were included in this study. Diagnosis was based on clinical findings, and/or the presence of joint purulent material, and/or bacterial pathogen isolation from joint fluid/synovial membrane/blood cultures and response to antibiotics. Data analysis was performed using SPSS 20.

RESULTS

Patients had a mean age of 61.1 ± 18.8 years, without sex predominance. 26.5 % had an infection ≤ 15 days before septic arthritis diagnosis. Besides previous infection, 57.4 % had ≥ 1 risk factors for septic arthritis, most commonly pharmacological immunosuppression (20.6 %), diabetes mellitus type 2 (19.1 %) and rheumatoid arthritis (17.6 %). The knee was the most often affected (54.3 %). Only 39.7 % presented fever from clinical onset until hospital admission (mean 13.4 ± 18.9 days). Leucocytosis was present in 45.6 % of patients, elevated erythrocyte sedimentation rate (ESR) in 75 % and elevated C-reactive protein (CRP) in 97.1 %. 5.9 % had articular damage attributable to septic arthritis. An infectious agent was isolated in 41.2 % of patients, with Staphylococcus aureus being the most frequent. 38.7 % of synovial fluid and 23.5 % of synovial membrane cultures were positive. Patients with an identified infectious agent have no significant differences other than more days of hospitalisation (p = 0.003) and in-hospital antibiotic treatment (p = 0.017).

CONCLUSION

Synovial fluid and synovial membrane cultures more often identified pathogens compared to blood or urine cultures. Patients with and without an identified infectious agent have similar demographic, clinical, laboratory and radiographic characteristics.

Rapid in situ chondrocyte death induced by Staphylococcus aureus toxins in a bovine cartilage explant model of septic arthritis

OBJECTIVE

To assess in situ chondrocyte viability following exposure to a laboratory strain and clinical isolates of Staphylococcus aureus.

METHODS

Bovine cartilage explants were cultured in the presence of S. aureus 8325-4 (laboratory strain), clinical S. aureus isolates or non-infected culture medium of pH values 7.4, 6.4 and 5.4. All clinical isolates were isolated from the joint aspirates of patients presenting with S. aureus-induced septic arthritis (SA). At designated time points, in situ chondrocyte viability was assessed within defined regions-of-interest in the axial and coronal plane following live- and dead-cell image acquisition using the fluorescent probes 5-chloromethylfluorescein diacetate (CMFDA) and propidium iodide (PI), respectively, and confocal laser-scanning microscopy (CLSM). Cartilage water content, following S. aureus 8325-4 exposure, was obtained by measuring cartilage wet and dry weights.

RESULTS

S. aureus 8325-4 and clinical S. aureus isolates rapidly reduced in situ chondrocyte viability (>45% chondrocyte death at 40 h). The increased acidity, observed during bacterial culture, had a minimal effect on chondrocyte viability. Chondrocyte death commenced within the superficial zone (SZ) and rapidly progressed to the deep zone (DZ). Simultaneous exposure of SZ and DZ chondrocytes to S. aureus 8325-4 toxins found SZ chondrocytes to be more susceptible to the toxins than DZ chondrocytes. Cartilage water content was not significantly altered compared to non-infected controls.

CONCLUSIONS

Toxins released by S. aureus have a rapid and fatal action on in situ chondrocytes in this experimental model of SA. These data advocate the prompt and thorough removal of bacteria and their toxins during the treatment of SA.

Spontaneous septic arthritis in a patient without trauma, coinfection, or immunosuppression

Septic arthritis is a rare infection, most often affecting the knee and hip [1]. Infections are often secondary to joint repair or replacement surgery, systemic infection, or intravenous recreational drug use [1,2].Diabetes, rheumatoid arthritis, hepatic dysfunction, and immunosuppression are common risk factors [1,2]. Although septic arthritis can occur spontaneously, such occurrences are rare. We report a case of a previously healthy 54-year-old woman with no known risk factors presenting to a freestanding emergency department with 5 days of shoulder pain.

Epidemiology of septic arthritis of the knee at Hospital das Clínicas, Universidade de São Paulo

Background

Septic arthritis is an infrequent disease although very important due to the possibility of disastrous outcomes if treatment is not adequately established. Adequate information concerning the epidemiology of septic arthritis is still lacking due to the uncommon nature of the disease as well as the struggle to establish a correct case-definition.

Objective

To epidemiologically characterize the population seen at Hospital das Clínicas, University of São Paulo with a diagnosis of septic arthritis between 2006 and 2011.

Methods

Sixty-one patients diagnosed with septic arthritis of the knee between 2006 and 2011 were retrospectively evaluated. The patients’ clinical and epidemiological characteristics, the microorganisms that caused the infection and the patients’ treatment and evolution were analyzed.

Results

Septic arthritis of the knee was more common among men, with distribution across a variety of age ranges. Most diagnoses were made through positive synovial fluid cultures. The most prevalent clinical comorbidities were systemic arterial hypertension and diabetes mellitus, and the most commonly reported joint disease was osteoarthritis. Staphylococcus aureus was the prevailing pathogen. Fever was present in 36% of the cases. All patients presented elevation in inflammatory tests. Gram staining was positive in only 50.8% of the synovial fluid samples analyzed. Six patients presented complications and unfavorable evolution of their condition.

Conclusion

S. aureus is still the most common pathogen in acute knee infections in our environment. Gram staining, absence of fever and normal leukocyte count cannot be used to rule out septic arthritis.

Twelve-month outcome following septic arthritis in children

There are very few literature data from the last two decades on the rate of complications following septic arthritis in children. This retrospective chart review shows that 10% of children admitted for septic arthritis to our institution suffered from clinically significant complications at 12 months following diagnosis. Forty-four children met our inclusion criteria, of whom 59% were male and 57% were culture positive. The most common causative organism was Staphylococcus aureus (76%), of which only 8% were methicillin-resistant S. aureus. Poor prognostic factors were culture positivity, infancy (<2 years) and male sex. Our rate of dysfunction is lower than most published rates, which have historically been in the range 15 to 49% in developed countries.

Joint aspiration and injection and synovial fluid analysis

Joint aspiration/injection and synovial fluid (SF) analysis are both invaluable procedures for the diagnosis and treatment of joint disease. This chapter addresses (1) the indications, technical principles, expected benefits and risks of aspiration and injection of intra-articular corticosteroid and (2) practical aspects relating to SF analysis, especially in relation to crystal identification. Intra-articular injection of long-acting insoluble corticosteroids is a well-established procedure that produces rapid pain relief and resolution of inflammation in most injected joints. The knee is the most common site to require aspiration although any non-axial joint is accessible for obtaining SF. The technique involves only knowledge of basic anatomy and should not be unduly painful for the patient. Provided sterile equipment and a sensible, aseptic approach are used, it is very safe. Analysis of aspirated SF is helpful in the differential diagnosis of arthritis and is the definitive method for diagnosis of septic arthritis and crystal arthritis. The gross appearance of SF can provide useful diagnostic information in terms of the degree of joint inflammation and presence of haemarthrosis. Microbiological studies of SF are the key to the confirmation of infectious conditions. Increasing joint inflammation associates with increased SF volume, reduced viscosity, increasing turbidity and cell count and increasing ratio of polymorphonuclear:mononuclear cells, but such changes are non-specific and must be interpreted in the clinical setting. However, detection of SF monosodium urate and calcium pyrophosphate dihydrate crystals, even from un-inflamed joints during intercritical periods, allows a precise diagnosis of gout and calcium pyrophosphate crystal-related arthritis.

Serious group a streptococcal infections

The spectrum of illnesses caused by group A streptococcus (GAS) includes invasive infections, noninvasive infections, and noninfectious complications. Increasingly virulent infections associated with high morbidity and mortality have been observed since the late 1980s and continue to be prevalent in North America and worldwide. Penicillin remains the therapy of choice, with the addition of clindamycin recommended in high risk cases. Early recognition of GAS as the cause of these serious clinical syndromes is critical for timely administration of appropriate therapy. In this review, the pathophysiology, clinical manifestations, and treatment of invasive GAS infections are discussed.

Clinical management of septic arthritis

Septic arthritis is a rheumatologic emergency as joint destruction occurs rapidly and can lead to significant morbidity and mortality. Accurate diagnosis can be particularly challenging in patients with underlying inflammatory joint disease. This review outlines the risk factors for septic arthritis and summarizes the causative bacterial organisms. We highlight advances in antibiotic management with a focus on new drugs for methicillin-resistant Staphylococcus aureus (MRSA) and discuss the use of adjunctive therapies for treatment of septic arthritis in adults.

Septic arthritis of the knee: the use and effect of antibiotics prior to diagnostic aspiration

Septic arthritis of the native knee joint and total knee arthroplasty both cause diagnostic and treatment issues. There is no gold standard test to diagnose a joint infection and the use of joint aspiration is commonly relied on. It is widely accepted by orthopaedic surgeons that antibiotics should be withheld until aspiration has been performed to increase the odds of identifying an organism. Patients often present to other specialties that may not be as familiar with these principles.

Our study found that 25 (51%) of the 49 patients treated for septic arthritis of the native or prosthetic knee in our unit over a 3-year period had received antibiotics prior to discussion or review by the on-call orthopaedic service. Patients were significantly less likely to demonstrate an organism on initial microscopy (entire cohort: p=0.001, native knees: p=0.006, prosthetic knees: p=0.033) or on subsequent culture (entire cohort: p=0.001, native knees: p=0.017, prosthetic knees: p=0.012) of their aspirate if they had received antibiotics. The sensitivity of microscopy in all patients dropped from 58% to 12% when patients had received antibiotics (native knees: 46% to 0%, prosthetic knees: 72% to 27%). The sensitivity of the culture dropped from 79% to 28% in all patients when the patient had received antibiotics (native knees: 69% to 21%, prosthetic knees: 91% to 36%).

This study demonstrated how the management of patients with suspected cases of septic arthritis of the knee may be compromised by empirical administration of antibiotics. These patients were significantly less likely to demonstrate an organism on microscopy and culture of their initial aspirate. There is a significant high false negative rate associated with knee aspiration with prior administration of antibiotic therapy.

Subtalar joint septic arthritis in a patient with hypogammaglobulinemia

The clinical presentation of a monoarticular, red, hot, and swollen joint has many possible diagnoses, including septic arthritis, which is 1 of the most devastating. The morbidity associated with this pathologic process involves permanent joint damage and the potential for progression to systemic illness and, even, mortality. The common risk factors for joint sepsis include a history of rheumatoid arthritis, previous joint surgery, joint prosthesis, intravenous drug abuse, alcoholism, diabetes, previous intra-articular steroid use, and cutaneous ulceration. The diagnosis is primarily determined from the culture results after arthrocentesis and correlation with direct visualization, imaging, and various serologies, including synovial analysis. In the present report, a case of an insidious presentation of subtalar joint septic arthritis and its association with a unique patient presentation concomitant with primary immunodeficiency and culture-proven Myocplasma hominis infection is discussed. Septic arthritis has a predilection for the lower extremities and typically is isolated to the hip or knee, with less common involvement of the ankle or metatarsophalangeal joints. Owing to the uncommon nature of primary immunodeficiency disorders and the paucity of studies discussing their association with septic arthridites, we aimed to raise awareness of subtalar joint septic arthritis and to provide a brief overview of the pathogenesis as it presented in a 33-year-old male with X-linked hypogammaglobulinemia/agammaglobulinema.