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

Arthroscopic treatment of septic arthritis of the elbow

HYPOTHESIS

Septic arthritis of the elbow is a serious orthopedic concern associated with high morbidity and mortality rates, traditionally treated with open exposure of the elbow joint. This study was performed to describe the outcome of arthroscopic treatment of septic elbow arthritis.

METHODS

From May 2000 through January 2008, 12 patients with septic elbow arthritis were treated arthroscopically at the Mayo Clinic, Rochester, Minnesota, a large medical center. We reviewed the patients' medical records concerning variables such as history and clinical findings, previous elbow history, surgical procedure, cultured organism, and follow-up. Using the Oxford Elbow Score and the Mayo Elbow Score, we examined current level of pain, function, and social-psychological aspects. Six patients died before initiation of this study and were therefore only studied retrospectively.

RESULTS

Septic elbow arthritis without pre-existing elbow problems shows excellent outcomes after arthroscopic treatment, with scores for absence of pain, function, social-psychological well-being, and range of motion of 97.9%, 100%, 95.8%, and 100%, respectively. When elbows were treated arthroscopically within 2 days after the onset of clinical symptoms suggesting bacterial elbow arthritis, maximum scores of 100% were noted for all aspects. Positive elbow history before infection and reoperation were associated with poor outcome scores, with 62.5%, 85.4%, and 50% for absence of pain, function, and social-psychological well-being, respectively.

CONCLUSION

Septic elbow arthritis occurs often in the debilitated, immunocompromised patient. Arthroscopic intervention is a reasonable alternative to open treatment. In this small series, the acutely septic elbow was successfully treated in the majority of patients, although the overall patient mortality rate remains high.

The fate of acutely inflamed joints with a negative synovial fluid culture

PURPOSE

The purpose of this study was to evaluate the management and fate of acutely inflamed joints with a negative synovial fluid culture.

METHODS

Between January and December 2009, all the patients who presented to our institution with an acutely inflamed joint and were subjected to microbiological assessment of their synovial fluid, were included in the study. Patients with a positive synovial fluid culture, a prosthetic joint replacement in situ and where an aspirate was obtained for a rheumatological diagnosis were excluded. This cohort was then divided into two groups depending on whether a diagnosis could be established through the course of their treatment. Group I included patients in whom a diagnosis could be established and group II included patients in whom a diagnosis could not be established. A thorough review of the patients' medical records and the hospital database was performed. Following this, a database consisting of the patient demographics, clinical features, investigations, treatment and outcome was created.

RESULTS

A total of 144 patients met the inclusion criteria (group I: 95, group II: 49). The most commonly affected joint in both the groups was the knee. The average time to presentation was shorter in group II. Clinical findings at presentation were comparable in both groups. However, inflammatory markers were more likely to be raised in group II in comparison with group I. Eighty-two percent of group II required antibiotic treatment compared with 15% of group I. The mean duration of antibiotic treatment in group I was ten days and in group II was 26 days. Mean hospital stay differed significantly between the two groups, with group II being more than twice as long as compared with group I (p=0.001). The rate of mortality was also higher in group II (8.2%, p=0.03).

CONCLUSION

Our study shows that patients presenting with an acutely inflamed joint and a negative synovial fluid culture in whom a diagnosis cannot be established during their hospital stay have a longer hospital stay and an increased rate of mortality as compared with patients in whom a diagnosis can be established.

Concomitant septic arthritis in crystal monoarthritis

OBJECTIVE

In acute monoarthritis, the presence of crystals in synovial fluid may lead to a diagnosis of crystal arthritis (CA) before septic arthritis (SA) can be excluded by culture. We aimed to identify the frequency of coexistence of CA with SA and to compare these with regard to synovial fluid microscopy, C-reactive protein (CRP), and blood culture.

METHODS

We examined 1612 synovial aspirates from 2004 to 2009 retrospectively. Of these, 104 patients with clinically significant SA were identified. These were compared to 295 patients with isolated CA.

RESULTS

Five percent of joints with CA had concomitant infection. A high synovial white blood cell (WBC) count and elevated CRP (> 100 mg/l) were predictive of concomitant SA with a sensitivity of 86.4%, specificity of 48.3% and 54.6%, and negative predictive values of 98.5% and 98.7%, respectively. In patients with SA who had a blood culture, 42.5% were positive with a matching organism. SA of the shoulder had a 90% rate of bacteremia.

CONCLUSION

Crystals alone in synovial fluid from acute monoarthritis cannot exclude SA, as CA and SA frequently coexist. High WBC counts and elevated CRP are common to both SA and CA. Blood cultures should be collected and septic arthritis considered, even when crystals are present, particularly if the shoulder is affected. The exception is when Gram stain is negative and the CRP is < 100 mg/l and joint WBC count is < 10,000/μl. In these circumstances it is very unlikely that there will be concomitant SA.

What's New in the Management of Bacterial Septic Arthritis?

Septic arthritis is a common rheumatological emergency requiring prompt diagnosis and treatment, since delays in management can lead to high morbidity and mortality. In this review article, we discuss the epidemiology and recent advances in knowledge of the pathogenesis of septic arthritis, with a special emphasis on various bacterial and host factors involved in mediating the inflammatory process and the potential for targeted therapy to modulate the immune response. Recent advances in laboratory and imaging techniques are reviewed along with treatment and potential new therapies.

An unexpected diagnosis of methicillin-resistant Staphylococcus aureus septic arthritis

Hand infections can result in serious tissue damage and gross functional impairment. This is particularly true in the case of septic arthritis, the most destructive of all joint disease. We report the first case of methicillin-resistant Staphylococcus aureus septic arthritis of the distal interphalangeal joint to have occurred in a patient devoid of all risk factors traditionally associated with a hospital-associated infection (HA-MRSA). The afflicted patient's only exposure to the pathogen was during her role as a community carer for an asymptomatic carrier. Delayed treatment allowed the infection to rapidly destroy surrounding soft tissue and necessitate in the need for arthrodesis. It is, therefore imperative that clinicians maintain a low index of suspicion for methicillin-resistant Staphylococcus aureus as the causative pathogen in similar cases. Consequently, consideration of empirical antibiotic therapy for this patient subgroup is discussed.

Rat bite fever as a presenting illness in a patient with AIDS

The etiology of culture-negative septic arthritis is poorly characterised in persons infected with human immunodeficiency virus (HIV). New molecular methods may assist in the investigation of culture-negative infections of sterile sites, including septic arthritis. We describe the first case of septic arthritis due to the cause of rat bite fever (RBF), Streptobacillus moniliformis, confirmed by 16S rRNA sequence analysis, in a patient with newly diagnosed HIV infection.

Arthroscopic management of septic arthritis of the wrist

Bacterial septic arthritis of the wrist is a joint-threatening emergency that is often treated by open irrigation and debridement (I and D). There is evidence that patients with isolated septic arthritis of the wrist require fewer operations and have a shorter hospital stay when treated arthroscopically. This article describes the surgical technique for arthroscopic I and D of the wrist and discusses the indications and benefits of arthroscopic versus open I and D for septic arthritis of the wrist.

Risk of septic arthritis in patients with rheumatoid arthritis and the effect of anti-TNF therapy: results from the British Society for Rheumatology Biologics Register

Objectives

To evaluate the risk of septic arthritis (SA) in patients with rheumatoid arthritis (RA) treated with anti-tumour necrosis factor (TNF) therapy.

Methods

Using data from the British Society for Rheumatology Biologics Register, a prospective observational study, the authors compared the risk of SA between 11 881 anti-TNF-treated and 3673 non-biological disease-modifying antirheumatic drug (nbDMARD)-treated patients.

Results

199 patients had at least one episode of SA (anti-TNF: 179, nbDMARD: 20). Incidence rates were: anti-TNF 4.2/1000 patient years (pyrs) follow-up (95% CI 3.6 to 4.8), nbDMARD 1.8/1000 pyrs (95% CI 1.1 to 2.7). The adjusted HR for SA in the anti-TNF cohort was 2.3 (95% CI 1.2 to 4.4). The risk did not differ significantly between the three agents: adalimumab, etanercept and infliximab. The risk was highest in the early months of therapy. The patterns of reported organisms differed in the anti-TNF cohort. Prior joint replacement surgery was a risk factor for SA in all patients. The rate of postoperative joint infection (within 90 days of surgery) was 0.7%. This risk was not significantly influenced by anti-TNF therapy.

Conclusions

Anti-TNF therapy use in RA is associated with a doubling in the risk of SA. Physicians and surgeons assessing the RA patient should be aware of this potentially life-threatening complication.

[Musculoskeletal puncture, injection and infiltration: swiss rheumatologists' point of view]

Arthrocentesis, injection and infiltration of joints and soft tissues belong to the basic procedures in rheumatology. The indications and the practical performance are based on experience and tradition. Nowadays, a crucial reappraisal and adaption of indications and technical aspects appear important in the light of new evidence and technical developments. The main indications for puncture remain the search of an infectious arthritis and reduction of intra-articular pressure due to effusion. Good indications for the injection of glucocorticoids are inflammation in sterile joints and activated osteoarthritis. The local infiltration with corticosteroids in mechanically induced enthesopathies at the lateral epicondyle of the humerus or at the plantar fascia have to be questioned in the light of recent publications which show that this common practice is associated with a poorer outcome than without injection.

Current concepts review: septic arthritis of the knee pathophysiology, diagnostics, and therapy

Treatments for bacterial arthritis of the knee joint are arthroscopic irrigation and debridement with systemic antibiotic medication. This article summarizes the relevant data of pathophysiology, stage of infection, symptoms, and diagnostics as well as stage-dependent treatment of bacterial arthritis of the knee joint. The major treatment principles are joint decompression, elimination of the causative organisms by intensive irrigation of the joint with elimination of proteolytic and lysosomal enzymes. Debridement of necrotic soft tissues with the aim of preserving the synovial membrane as an immune-competent structure, and a natural barrier, is recommended. Good results in treating knee infections have been achieved with arthroscopic joint revision and stage-dependent surgical therapy. The infection staging I-IV suggested by Gächter was used most commonly, which mainly reflects the pathophysiologic infection stages. For stages I-III, arthroscopic joint decompression with joint irrigation and debridement is effective and can be repeated in cases of persisting infection. The incidence of repeated arthroscopic joint irrigation depends on the initial stage of the infection and varies between 0 and 41% of the cases. For stage IV infections, the open revision is needed or in seldom cases of therapy failure under initial or repeated arthroscopic joint revision. The success rate of healing infections by arthroscopic irrigation was high with 90-100%.

Microbiological profile of haematogenous osteoarticular infections in children

INTRODUCTION

Staphylococcus aureus, Kingella kingae and β-hemolytic streptococcus are presently the most frequently identified bacteria in child haematogenous osteoarticular infection.

OBJECTIVE

To determine the microbiological profile (bacteria and antibiotic susceptibility) of osteoarticular infections in a paediatric hospital, so as to adapt treatment protocols to the ecology of the bacteria isolated.

PATIENTS AND METHODS

Prospective descriptive study, including children admitted for acute osteomyelitis or septic arthritis. A series of blood cultures was performed systematically on admission. In case of surgery, local samples were taken for bacteriology. Antibiotherapy was initiated and subsequently adapted to the bacteriological findings.

RESULTS

One hundred and six children were included. Thirty-five were under (Group 1) and 71 over 3 years of age (Group 2). Ninety-five underwent surgery. Peroperative samples were positive in 61 cases and blood culture in 23. Bacteria were isolated in 22 patients in G1. Extended-spectrum β-lactamase-producing Klebsiella pneumoniae was isolated in five neonates who had passed through intensive care. Staphylococcus aureus was the most frequently isolated bacterium in G2 (n=40), and was methicillin-resistant (MRSA) in six children.

DISCUSSION

Methicillin-susceptible Staphylococcus aureus was the most frequently isolated microorganism. Other than neonates who had passed through intensive care and the six patients with community-acquired MRSA infection, all isolated bacteria were susceptible to second-generation cephalosporins.

LEVEL OF EVIDENCE

II, prospective descriptive prognostic study.

Causative organisms and their antibiotic resistance patterns for childhood septic arthritis in china between 1989 and 2008

The goal of this study was to evaluate the array of causative organisms for septic arthritis in children and their antibiotic resistance patterns over a 20-year period at a single medical center. The medical records of children younger than 16 years with septic arthritis admitted to a hospital in China from 1989 to 2008 were retrospectively reviewed. A total of 158 cases of septic arthritis were studied, 70 from 1989 to 1998 and 88 from 1999 to 2008. Between the first and second decades, occurrence of serious illnesses decreased significantly from 44.3% to 28.4% (P<.04). The positive percentage was only 55.6% in the first decade and 44.82% in the second decade. The causative organisms of major significance between the 2 decades changed little, except methicillin-resistant Staphylococcus aureus (MRSA) increasing significantly. Staphylococci remained the major causative organisms for joint infection. The percentage of Staphylococcus aureus resistance to various antibiotics increased: 85% to 100% for penicillin, 58.8% to 75% for erythromycin, 0% to 31.3% for cefazolin, and 15% to 29.4% for multi-resistance. In the second decade, 4 MRSA stains were multi-resistant. However, gentamincin resistance remained at the same level. Antibiotic resistance of coagulase-negative staphylococci and gram-negative bacilli changed little. The incidences of osteomyelitis and joint dislocation decreased significantly, from 15.7% to 6% and 28.6% to 14.8%, respectively (P<.04). The distribution of causative organisms of septic arthritis in young patients changed slightly during the 20-year period, while antibiotic resistance of the major causative organisms increased and the incidences of serious illness-osteomyelitis and joint dislocation-decreased significantly.

What are we doing about septic arthritis? A survey of UK-based rheumatologists and orthopedic surgeons

This study aims to determine the current practices and beliefs of United Kingdom (UK)-based rheumatologists and orthopedic surgeons (OS) in managing septic arthritis (SA) and to determine awareness levels of national guidance. Two-hundred OS and 200 rheumatologists were sent a link to a web-based survey tool via email. Questions posed related to the management of SA, including the respondent's views on antibiotic therapy, joint drainage, which specialty should manage these cases, and also the clinician's evidence base. There were 354 functioning addresses with 182 responses (51%). One hundred fifty-one (77 OS, 74 rheumatologists) (43%) responses were complete and included for analysis. Eighty percent of rheumatologists and 82% of OS recommended 6-weeks total antibiotic therapy. Seventy-three percent in each group recommended 1-2 weeks intravenous therapy initially followed by oral continuation therapy. In patients at risk of methicillin-resistant Staphylococcus aureus (MRSA), 25% rheumatologists and 14% OS would ensure MRSA cover. Seventy-seven percent of rheumatologists and 66% of OS recommended surgical joint drainage; 22% and 27%, respectively, recommended repeated closed needle aspiration as their chosen method of joint drainage. Sixty-six percent of rheumatologists and 65% of OS believed OS should manage SA. Twenty-three percent of rheumatologists and 22% of OS quoted published guidance as their main evidence base in the treatment of SA. Only 24% of rheumatologists and 34% of OS quoted British Society of Rheumatology (BSR) guidance when asked if they were aware of any guidelines. Views of rheumatologists and OS are not that dissimilar in managing SA. Surprisingly, rheumatologists are more aggressive regarding the recommendation for surgical joint drainage. Within both groups, significant variation in management principles exists often discrepant to recommendations laid out by the BSR. There are poor awareness levels of the BSR guidelines.

Differences in MRI findings between subgroups of recent-onset childhood arthritis

BACKGROUND

MRI is sensitive for joint inflammation, but its ability to separate subgroups of arthritis in children has been questioned. Infectious arthritis (IA), postinfectious arthritis (PA), transient arthritis (TA) and juvenile idiopathic arthritis (JIA) are subgroups that may need early, different treatment.

OBJECTIVE

To determine whether MRI findings differ in IA, PA/TA and JIA in recent-onset childhood arthritis.

MATERIALS AND METHODS

Fifty-nine children from a prospective study of incidence of arthritis (n = 216) were, based on clinical and biochemical criteria, examined by MRI. Joint fluid, synovium, bone marrow, soft tissue and cartilage were scored retrospectively and analysed by Pearson chi-square test and logistic regression analysis.

RESULTS

Fifty-nine children had MRI of one station. IA was suggested by bone marrow oedema (OR 7.46, P = 0.011) and absence of T1-weighted and T2-weighted low signal intensity synovial tissue (OR 0.06, P = 0.015). Furthermore, soft-tissue oedema and reduced contrast enhancement in the epiphyses were more frequent in children with IA. JIA correlated positively with low signal intensity synovial tissue (OR 13.30, P < 0.001) and negatively with soft-tissue oedema (OR 0.20, P = 0.018). No significant positive determinants were found for PA/TA, but bone marrow oedema, soft-tissue oedema, irregular thickened synovium and low signal intensity synovial tissue was less frequent than in IA/JIA.

CONCLUSION

In children with high clinical suspicion of recent onset arthritis, there was a significant difference in the distribution of specific MRI features among the diagnostic groups.

Kynurenine inhibits chondrocyte proliferation and is increased in synovial fluid of patients with septic arthritis

Kynurenine, the major degradation product of tryptophan has been shown to directly damage various tissues. Its potential contribution to septic arthritis is unknown. In this study, we analyzed the putative diagnostic value of kynurenine for bacterial joint infection and its potential harmful effects on cartilage. In a prospective study 41 patients with a joint effusion who had undergone arthrocentesis were included. Tryptophan and kynurenine levels from synovial fluid were quantified by HPLC. Diagnostic value of kynurenine was evaluated and its effects on the proliferation of the chondrocyte cell line ATDC5 were determined. Synovial fluid kynurenine values from patients with septic arthritis (4.1 ± 0.8 µmol/L, n = 9) were significantly increased compared to patients with non-infectious inflammatory arthropathy (1.8 ± 0.2 µmol/L, n = 17) or osteoarthritis (1.2 ± 0.1 µmol/L, n = 15, p < 0.01). At a cut-off value of 2.28 µmol/L kynurenine had a sensitivity of 0.89 and a specificity of 0.87. Further, kynurenine inhibited chondrocyte (ATDC5) cell proliferation in a dose-dependent manner. Septic arthritis is associated with significantly increased values of synovial kynurenine. Furthermore kynurenine inhibits proliferation of chondrocytes, which strongly suggests a pathophysiological effect of kynurenine on cartilage in inflammatory arthropathies.

The complications of septic arthritis in the elderly

BACKGROUND AND AIMS

An epidemiological analysis of cases of spontaneous community acquired septic arthritis in an elderly population at a university teaching hospital.

METHODS

Confirmed cases of spontaneous septic arthritis in the over-65 population were studied. Patients with prosthetic joint infections were excluded from the study. Analysed data included initial presenting complaint and clinical examination, hematological and microbiological tests together with ultimate patient outcome.

RESULTS

There were 7 confirmed cases of spontaneous septic arthritis in the over 65 population in the past 6 months (2 hips, 5 knees). The mean age was 72.14 (range 65-82) with a mean length of stay of 49 days. Those with septic arthritis of the knee presented with swelling, pain and immobility. Hip cases presented with pain and immobility. All patients were systemically well at the time of presentation, with no other foci of infection detected after septic screening. All patients had confirmed aspirate and arthroscopic/arthrotomy infection. Staphylococcus aureus was isolated from 6 joint aspirations and Pseudomonas Aeruginosa from one patient. Complications of treatment included acute renal failure, cardio/respiratory failure, disseminated infection, and death (1 case).

CONCLUSION

Septic arthritis must be considered as a differential diagnosis in all patients with joint pain, swelling and immobility. This diagnosis is not confined to the pediatric population. A background of degenerative disease and occult presentation in the elderly may delay diagnosis. Sepsis must be considered in the elderly with joint pathology, and treatment must be initiated in a prompt and aggressive manner, to prevent sequelae.

Bacterial septic arthritis in adults

Symptoms and signs of septic arthritis are an important medical emergency, with high morbidity and mortality. We review the changing epidemiology of septic arthritis of native joints in adults, encompassing the increasing frequency of the disorder and its evolving antibiotic resistance. We discuss various risk factors for development of septic arthritis and examine host factors (tumour necrosis factor alpha, interleukins 1 and 10) and bacterial proteins, toxins, and enzymes reported to be important determinants of pathogenesis in mouse models. Diagnosis of disease is largely clinical, guided by investigations and the opinion of skilled clinicians. We emphasise the need for timely medical and surgical intervention-most importantly, through diagnostic aspiration of relevant joints, choice of suitable antibiotic, and appropriate supportive measures. Management is growing in complexity with the advent of novel and antibiotic-resistant causative microorganisms and within the current climate of increased immunosuppression. Findings from animal models and patients are shedding light on disease pathogenesis and the possibility of novel adjunctive treatments, including systemic corticosteroids, cytokines and anticytokines, and bisphosphonates.

RANKL-targeted therapy inhibits bone resorption in experimental Staphylococcus aureus-induced arthritis

INTRODUCTION

Bacterial arthritis causes rapidly progressing joint destruction in humans. We have shown that addition of bisphosphonates or corticosteroids to conventional antimicrobial agents decreases the activity of osteoclasts, thereby reducing bone destruction. Here we assess the effect of RANKL-targeted treatments using soluble receptor decoy and osteprotegerin (OPG) on the course and outcome of staphylococcal arthritis.

METHODS

Treatment was initiated 3 days after Staphylococcus aureus inoculation and included RANK-Fc, OPG-Fc, and OPG-Fc in combination with antibiotics. Control groups were treated with antibiotics, huFc, and PBS. Joints were evaluated for clinical signs of arthritis and histologically for bone and cartilage destruction. Bone mineral density (BMD) was evaluated using a peripheral quantitative computed tomography. Circulating markers of bone metabolism, inflammatory cytokines, and chemokines were analyzed in each group.

RESULTS

Mice treated with RANK-Fc or OPG-Fc in combination with antibiotics preserved total BMD and trabecular bone as compared to huFc or antibiotics. Treatment with RANK-Fc or OPG-Fc diminished the levels of bone resorption markers (osteocalcin, CTX-I, and TRACP5b). Neither RANK-Fc nor OPG-Fc influenced significantly the frequency and severity of arthritis.

CONCLUSIONS

Inhibition of RANKL signalling efficiently prevents bone loss in the mouse model of bacterial arthritis even when started in the overt phase of infection.

Meticillin-sensitive Staphylococcus aureus costochondritis in a healthy man

BACKGROUND

A 54-year-old previously healthy white man presented to hospital with fever, right parasternal pain and swelling over the right second and third costochondral joints. The symptoms had developed 1 week earlier.

INVESTIGATIONS

Physical examination, white blood cell count, erythrocyte sedimentation rate, C-reactive protein level, blood and urine culture, plain radiography and CT of the chest, (99m)Tc bone scintigraphy, ultrasound-guided needle aspiration of soft tissue mass, Gram staining and culture of aspirated fluid.

DIAGNOSIS

Meticillin-sensitive Staphylococcus aureus costochondritis.

MANAGEMENT

CT revealed a 2 x 5 cm soft tissue mass at the posterior aspect of the right second and third costochondral joints. The fluid aspirated contained Gram-positive cocci, and culture revealed the presence of meticillin-sensitive S. aureus. The patient received a 6-week course of flucloxacillin (2 g by intravenous injection every 6 h for 2 weeks, then 1 g orally every 6 h for 4 weeks). He responded well to treatment, and was discharged from hospital.

Diagnostic accuracy of neutrophil-derived circulating free DNA (cf-DNA/NETs) for septic arthritis

The release of "neutrophil extracellular traps" (NETs) has been identified as a novel immune response in innate immunity. NETs are composed of neutrophil-derived circulating free DNA (cf-DNA) and neutrophil cytoplasm-derived proteins such as proteases. In this study, we analyzed the putative diagnostic value of synovial cf-DNA/NETs for identification of septic arthritis. Forty-two patients with a joint effusion who had undergone arthrocentesis were included. From synovial fluid, cf-DNA/NETs (j-cf-DNA) levels were directly quantified. Diagnostic value of j-cf-DNA was compared with white blood cells (WBC), synovial white blood cells (j-WBC), C-reactive protein (CRP), j-IL-6, j-TNF alpha, j-IL-1 beta, and myeloperoxidase (j-MPO). Sensitivity, specificity, positive and negative predictive value, as well as ROC-curves for each parameter were calculated. Synovial fluid cf-DNA/NETs values from patients with septic arthritis (3,286 +/- 386 ng/ml, n = 9) were significantly increased compared to patients with noninfectious joint inflammation (1,040 +/- 208 ng/ml, n = 17) or osteoarthritis (278 +/- 34 ng/ml, n = 16, p < 0.01). In conjunction with j-cf-DNA, j-IL-6 and j-IL-1 beta were significantly elevated (p < 0.01), but WBC, CRP, and j-WBC were not. At a cut-off of 300 ng/ml, j-cf-DNA had a sensitivity of 0.89, a specificity of 1.0, a positive predictive value of 1.0, and a negative predictive value of 0.97. Receiver operation curves revealed largest areas under the curve for cf-DNA/NETs (0.933) and j-IL-6 (0.951). cf-DNA/NETs seem to be a valuable additional marker for the diagnosis of septic arthritis or periprosthetic infections. However, this result should be confirmed in a large clinical trial.

Medical vs surgical treatment for the native joint in septic arthritis: a 6-year, single UK academic centre experience

OBJECTIVE

Medical treatment (serial closed-needle aspiration) and surgical treatment (arthroscopy/arthrotomy combined with joint washout) are well-recognized methods to treat septic arthritis (SA) of native joints. We compared the outcome of proven SA based on the method of treatment.

METHODS

We reviewed case notes of adult patients who were admitted to our institution from January 2001 to December 2006 with proven SA (Newman Grade A organism isolated from the joint).

RESULTS

Thirty-two episodes were treated medically and 19 surgically (4 with arthrotomy, 15 with arthroscopy) in the study period. All had mono-articular SA. No significant difference in the age, symptom duration before treatment and duration of intravenous antibiotic therapy was present between the two groups. Medical treatment resulted in complete recovery in more patients (69 vs 53%, P = 0.24) but longer period of hospitalization [median (interquartile range), 16.5 (14-19) vs 15 (11-17), P = 0.34], although the difference between the groups was not significant. More surgically treated patients had deterioration in functional status at the time of discharge from the hospital (29 vs 44%, P = 0.27), but the difference between the groups was not statistically significant. Surgically treated patients required significantly more sessions of physiotherapy (mean +/- S.D., 7 +/- 2 vs 10 +/- 3, P = 0.002). Mortality was similar (one in each group).

CONCLUSION

Results from this study show that for the native joint SA, surgical treatment was not superior to the medical treatment and, therefore, highlight the need for careful case selection for surgical intervention.

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, the technical principles and the 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 requires a 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 is associated 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, allow a precise diagnosis of gout and of calcium pyrophosphate crystal-related arthritis.

Post-partum septic arthritis of the knee: a case report

INTRODUCTION

Septic arthritis is rare in the post-partum period. This is the first case of a post-partum staphylococcal septic arthritis of the knee reported.

CASE PRESENTATION

This report describes a lady who developed symptoms of septic arthritis of the knee within one month of giving birth.

CONCLUSION

The management of septic arthritis does not differ from standard practice when encountered in the post-partum period. Urgent washout of the joint and antibiotic usage is associated with a favourable outcome.

Effect of body mass index on the outcome of infections: a systematic review

It has not been adequately evaluated whether the outcome of infections differs by body-weight category. We performed a systematic review of relevant studies. Eleven studies (one retrospective and 10 prospective cohort studies) were included in this review, involving a total of 3159 hospitalized patients or nursing home residents. Most studies (6/11) referred to lower respiratory tract infections. Seven studies showed an association of patient outcome (mortality in 6/7 studies) with body-weight category. This was shown in multivariate analysis in 4/5 studies that reported relevant data. Obese or morbidly obese patients with infections had worse outcome compared with the rest of the patients or with normal-weight patients, in 4/7 studies that reported relevant data; findings were not significant in the remaining three studies. Patients in the lowest body mass index (BMI) group had worse outcome compared with all other groups combined, in 3/5 studies that reported relevant data; findings were not significant in the remaining two studies. Low BMI was associated with worse outcome in patients with lower respiratory tract infections in 3/4 relevant studies. Although not consistently reported, an association of both ends of the BMI distribution with worse outcome of infections is plausible and merits further investigation.

Septic arthritis of the pubic symphysis in an 11-year-old boy

Septic arthritis of the pubic symphysis is a rare condition but one which has typical clinical characteristics and known risk factors. It should be considered in the differential diagnosis of all children presenting with groin or hip pain that is exacerbated when walking. Clinical suspicion should prompt magnetic resonance imaging. We report such a case in an 11-year-old boy, discuss current knowledge of its epidemiology and microbiology, and outline recommended practice for investigation and treatment.

[Polyarticular septic arthritis: analysis of 19 cases]

OBJECTIVE

Polyarticular septic arthritis accounts for 15% of all septic arthritis, but there are few references in the literature. We describe characteristics of patients with polyarticular septic arthritis in a rheumatology service.

PATIENTS AND METHOD

Retrospective analysis of patients with septic arthritis involving more than one joint. Only patients with positive culture of synovial fluid were included. Clinical, analytical and radiological variables are reviewed.

RESULTS

19 patients (14 male) had a polyarticular infection. Mean age was 55 years. Mean time from onset to diagnosis was 6 days. The knee was the most commonly involved joint, followed by ankle. The mean number of joints involved per patient was 3. Risk factors included diabetes, chronic renal or hepatic disease, gout and rheumatoid arthritis. Most commonly isolated agents were S. aureus (47%) and S. agalactiae (21%). Blood cultures were positive in 52,6% and 15.8% had septic shock. Scintygraphic bone scan showed a polyarticular uptake. Mean duration of antibiotic therapy was 46±27 days. Clinical outcome was good in 52,6%, complicated in 26%, and mortality rate was 15.8% (3 cases). Joint debridement was performed in 21%.

CONCLUSIONS

Multiple joint involvement does not exclude the diagnosis of septic arthritis. Inflammatory arthritis is an important risk factor. S. aureus in the main infectious agent. The morbidity and mortality of this condition are important, so we need to maintain a high index of suspicion for the condition.

Hematogenous infection of a total knee arthroplasty with Klebsiella pneumoniae in association with occult adenocarcinoma of the cecum

Acute hematogenous septic arthritis caused by the genus Klebsiella is extremely rare. This case report describes a prosthetic joint infected with Klebsiella pneumoniae via acute hematogenous spread. This is the first reported case of K pneumoniae pyogenic arthritis with a coexisting occult colonic adenocarcinoma. The patient was treated successfully with open irrigation, debridement, polyethylene spacer exchange, and chronic suppressive antibiotics. The underlying colon cancer was recognized early, and the patient responded well to surgery and adjuvant chemotherapy. This case illustrates the importance of having a high index of suspicion for underlying pathologic processes when an unusual organism presents as the cause of septic arthritis.

[Septic arthritis: practical diagnosis and new treatments]

Septic arthritis remains a major challenge to physicians because the increasing frequency of certain microorganisms to become in antibiotic-resistant and persistent difficulties regarding both early diagnostics and proper treatment of subjects with joint infections. This paper will review current diagnostics test and their contribution to the rapid evaluation of joint infection. Importantly, updated therapeutic suggestions will be presented which, when appropriately applied, should diminish the risks of sequelae following infectious arthritis.

MR imaging evaluation of disorders of the chest wall

Chest wall lesions constitute a diverse group of thoracic diseases, including those of soft tissue and osseous origin. MR imaging, with its superior tissue-resolving capability and multiplanar image acquisition, is an important tool for assessing chest wall lesions. In this article, the authors review common and uncommon diseases of the chest wall, with an emphasis on the MR imaging characteristics of these diseases. Among the diseases they discuss are diseases of the soft tissue including lipoma, hibernoma, liposarcoma, hemangioma, and lymphoma. They also examine diseases of the osseous thorax, including benign osseous tumors, fibrous dysplasia, and aneurysmal bone cyst. In addition, they discuss such malignant osseous tumors as osteosarcoma and Ewing's sarcoma.

Rheumatoid arthritis is the major risk factor for septic arthritis in rheumatological settings

Septic arthritis (SA) is a clinical emergency with considerable morbidity and mortality that can lead to rapid joint destruction and irreversible functional loss. The reported incidence varies from 2-5 cases/100,000 person-years in the general population to 70 cases/100,000 person-years among patients with rheumatoid arthritis. In fact, individuals with rheumatoid arthritis are at particular risk for developing SA. This may be due to several reasons: joint disease predisposes to bacterial joint colonization and RA itself and its treatment with corticosteroids, disease-modifying antirheumatic drugs (DMARDs) and biological therapies may decrease the immune function required for protection from pathogens. Steroids and DMARDs seem to affect the leukocyte synovial count; indeed, RA patients with SA have a leukocyte count in synovial fluid (SF) lower than patients with SA without underlying rheumatic diseases. The diagnosis of SA in RA patients can be difficult because the development of a hot painful joint is often confused with a relapse of the underlying joint disease leading to delay in diagnosis. For this reason the microscopic analysis and culture of synovial fluid are crucial to exclude septic arthritis.

Lactate and T (2) measurements of synovial aspirates at 1.5 T: differentiation of septic from non-septic arthritis

OBJECTIVE

The aim of this study was to differentiate septic from non-septic arthritis by measuring lactate concentration with (1)H magnetic resonance spectroscopy (HMRS) and by estimating total protein content with the assessment of T (2) values.

MATERIALS AND METHODS

In 30 patients with acute arthritis, synovial fluid was aspirated. Lactate concentrations were analyzed with single voxel HMRS at 1.5 T. T (2) relaxation times were mapped with a multi-spin echo sequence. All samples underwent microbiological testing and routine laboratory analysis to quantify lactate concentration and total protein content. Values obtained in septic and non-septic arthritis were compared with a Mann-Whitney U test.

RESULTS

Synovial fluid from patients with septic arthritis (n = 10) had higher concentrations of lactate (11.4 +/- 4.0 mmol/L) and higher total protein content (51.8 +/- 10.7 g/L) than fluid obtained in non-septic arthritis (n = 20; 5.2 +/- 1.1 mmol/L and 40.4 +/- 6.9 g/L, respectively, p < 0.001 and <0.01, respectively). Measured lactate concentrations and T (2) relaxation times (as an indicator of total protein content) were moderately correlated to laboratory-confirmed lactate concentration (r (2) = 0.71) and total protein content (r (2) = 0.73). Markedly increased lactate concentrations (>6 mmol/L) in combination with low T (2) values (<550 ms) identify septic arthritis with a sensitivity of 70% and a specificity of 89%.

CONCLUSION

Spectroscopic measurements of lactate concentration in combination with the estimation of protein content using T (2) may be of value in the differentiation of septic from non-septic arthritis.

Community-associated methicillin-resistant Staphylococcus aureus

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has emerged over the last decade across the United States and the world, becoming a major pathogen in many types of community-acquired infections. Although most commonly associated with minor skin and soft tissue infections, such as furuncles, CA-MRSA also can cause necrotizing fasciitis, pyomyositis, osteoarticular infections, and community-acquired pneumonia. This article discusses the epidemiology, diagnosis, and management of these infections from the perspective of the emergency physician.