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

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.

Hematogenous septic ankle arthritis

Ankle infection is a serious problem with limited published information on microbiology and associated morbidities. We describe the laboratory findings, microbiology, and occurrence of adjacent osteomyelitis in patients with hematogenous septic ankle arthritis. We retrospectively reviewed 30 patients with hematogenous septic arthritis of the ankle admitted over a 10-year period. Twenty-two patients were male and eight female. The mean age was 46 years (range, 23-67 years). C-reactive protein and erythrocyte sedimentation rate were elevated in all patients, but the peripheral white blood cell count was elevated in only 47% of patients. Staphylococcus aureus (S. aureus) was the most common pathogen, isolated in 13 (54%) of the 24 patients with positive cultures; four of these isolates (four of 24; 17% of positive cultures) were oxacillin-resistant. Four (17%) of the 24 patients with positive cultures had a mycobacterial infection. We identified adjacent osteomyelitis in 30% of patients, which was considerably associated with the presence of patient comorbidities. S. aureus is the most common pathogen in septic ankle arthritis and empiric antibiotic therapy is recommended. Adjacent osteomyelitis may be present and a high index of suspicion is necessary in patients with comorbidities.

LEVEL OF EVIDENCE

Level III, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Septic arthritis in haemodialysis patients: a seven-year multi-centre review

PURPOSE

To determine relevant demographics, clinical features, and outcomes for septic arthritis in patients on haemodialysis for end-stage renal failure.

METHODS

A multi-centre retrospective review was performed from 1999 to 2005.

RESULTS

15 cases were identified. The mean age of the patients at diagnosis was 67 (range, 23-89) years and 11 were male. All had multiple co-morbidities and additional risk factors for sepsis. The primary sources of sepsis were dialysis access-related (n=12), unknown in 2, and unrelated soft tissue infection in one. All patients presented with acute monoarticular symptoms; the knee joint was affected in 11 patients. The white cell count, neutrophil count, and C-reactive protein concentration were elevated in 10, 10, and 15 patients, respectively. All patients had positive synovial fluid cultures and blood cultures were positive in 14. Organisms isolated were all skin commensals, being staphylococcal in 13 and streptococcal in 2. Six patients had concomitant rheumatological disease (gout in 4, pseudogout in one, and rheumatoid arthritis in one). Two had urate crystals in the synovial fluid (noted by microscopy). All patients underwent antimicrobial therapy for a mean of 36 days, together with joint washouts and debridement. 12 patients were cured of infection; 2 developed chronic sepsis secondary to localised osteomyelitis; and one died of sepsis.

CONCLUSION

Septic arthritis is a potentially devastating condition. Early and aggressive joint lavage and debridement combined with appropriate antimicrobial therapy is imperative. A high index of suspicion is necessary in haemodialysis patients; the diagnosis of septic arthritis must be presumed until proven otherwise.

Septic arthritis in Iceland 1990-2002: increasing incidence due to iatrogenic infections

Objectives:

To assess the impact of increased number of diagnostic and therapeutic joint procedures on the incidence and type of septic arthritis (SA).

Methods:

All cases of SA in Iceland from 1990–2002 were identified by thorough review of the available medical information. The results of synovial fluid cultures from every microbiology department in Iceland were checked and positive culture results reviewed, as well as patient charts with a discharge diagnosis of septic arthritis (International Statistical Classification of Diseases and Related Health Problems (ICD) code M009).

Results:

A total of 253 cases of SA (69 children and 184 adults) were diagnosed in Iceland in 1990–2002, giving an average incidence of 7.1 cases/100 000 inhabitants. The incidence of SA increased from 4.2 cases/100 000 in 1990 to 11.0 cases/100 000 in 2002. This rise in SA was primarily observed in adults where the incidence rose by 0.61 cases/100 000 per year (p<0.001). SA was iatrogenic in 41.8% of adults and the number of iatrogenic infections increased from 2.8 cases/year in 1990–1994 to 9.0 cases/year in 1998–2002 (p<0.01). The annual number of arthroscopies increased from 430 in 1990–1994 to 2303 in 1998–2002 (p<0.001) and there was a correlation between the total usage of intra-articular drugs in Iceland and the incidence of SA (p<0.01). The frequency of post-arthroscopy SA was 0.14% and post-arthrocentesis SA 0.037%.

Conclusions:

The incidence of SA has increased in recent years due to an increased number of arthroscopies and joint injections. Although the frequency of SA per procedure has not changed, these results emphasise the importance of sterile technique and firm indications for joint procedures.

Methicillin resistant Staphylococcus aureus versus methicillin sensitive Staphylococcus aureus adult haematogenous septic arthritis

INTRODUCTION

Septic arthritis is an orthopaedic emergency and Staphylococcus aureus (SA) is the number one cause. Methicillin resistant Staphylococcus aureus (MRSA) is increasing in incidence but how it differs from methicillin sensitive Staphylococcus aureus (MSSA) septic arthritis is unclear. Our aim was to delineate the differences in clinical features and outcomes between patients with MRSA and MSSA septic arthritis.

MATERIALS AND METHODS

We performed a retrospective review of all adult patients presenting to our institute over a 5 year period from June 2000 to June 2005 with haematogenous septic arthritis. We identified 15 cases of MRSA and 43 cases of MSSA septic arthritis. Fisher's exact test and the Student's t-test were used in analysis.

RESULTS

MRSA and MSSA predominantly affected males 60 versus 79%. MRSA cases were older with a mean age of 76 versus 44 years (P < 0.05), and had more comorbidities with a mean of 2.7 versus 1.35 (P < 0.05). In MRSA and MSSA cases the main sources of sepsis were unknown (20 vs. 47%), intravenous lines (47 vs. 2%), soft tissue infection (13 vs. 2%) and intravenous drug use (7 vs. 49%). MRSA was significantly more associated with intravenous line sepsis (P < 0.05), soft tissue infection (P = 0.05) and to be nosocomial (P < 0.05). MSSA was significantly more associated with IVDU (P < 0.05). Presentation was similar in both groups although MRSA patients were significantly more likely to be pyrexial (80 vs. 40%, P < 0.05) and to have glenohumeral involvement (P < 0.05) while MSSA was significantly more likely to affect the knee (P < 0.05). There were no significant differences between the total length of antimicrobial therapy in MRSA and MSSA patients (43 vs. 38 days, P > 0.2), or the number of surgical interventions required (1.8 vs. 1.6, P > 0.2). However MRSA patients were significantly more likely to be placed on inappropriate empirical antimicrobials pending sensitivities (93 vs. 0%, P < 0.05). Outcomes were similar in MRSA and MSSA patients with no significant differences in recurrences (0 vs. 10%, P > 0.2) or sepsis related mortality (13.3 vs. 6.9%, P > 0.2). MRSA, however, did show a strong towards a higher all cause 6 month mortality (26 vs. 7%, P = 0.07).

CONCLUSION

MRSA septic arthritis tends to affect older patients with multiple comorbidities and has a tropism for the glenohumeral joint while MSSA has a tropism for the knee. We did not find a significant difference in required length of antimicrobials, number or requirement of operative interventions or outcomes in terms of number of recurrences or sepsis related mortality. However MRSA septic arthritis patients were found to have a strong trend towards an increased all cause 6 month mortality and were significantly more likely to receive inappropriate empirical antimicrobials.

Another look at synovial fluid leukocytosis and infection

Synovial fluid white blood cell counts are considered to be useful in diagnosing infectious arthritis, however, considerable overlap exists between infectious and noninfectious types of inflammatory arthritis. We undertook this review of synovial fluid studies at our institution to better define this degree of overlap and characterize the features of infectious arthritis in relationship to synovial fluid white cell counts. The records of 202 consecutive patients with synovial fluid white blood cell counts >2000/mm were reviewed. Infectious arthritis was diagnosed in 77% (10/13) of patients with counts >100,000, 47% (8/17) in the 50,000-100,000 range, and 5% (9/172) with counts <50,000. Crystal-induced arthritis and rheumatoid arthritis made up 81% of patients in the 15,000-50,000 range. Overall, 10 of 27 (37%) cases of infectious arthritis had white cell counts >100,000, and 18 of 27 (67%) had counts >50,000. A majority of these infections (14/18) were related to Staphylococcus aureus, while 5 of 7 infections associated with counts <20,000 were associated with atypical organisms. This study confirms that a majority of patients with very high synovial fluid white blood cell counts have infectious arthritis, and that the likelihood of infection is markedly reduced, but certainly not excluded, below this level. The presence of atypical infections in a small percentage of patients with low counts emphasizes the importance of clinical judgment in evaluating all patients with inflammatory arthritis, regardless of synovial fluid white cell counts.

Septic arthritis due to extended spectrum beta lactamase producing Klebsiella pneumoniae

CASE REPORT

Septic arthritis due to Klebsiella species is a rare but serious infection that may destroy a joint and cause serious immobility. This is a report of two immunocompromised adult patients presenting with acute septic arthritis due to extended spectrum beta lactamase producing Klebsiella pneumoniae. The infection was treated successfully with a course of meropenem and amikacin in combination with early arthroscopic washout of the joint. Little information has been published on the management of this infection. We are therefore presenting a systematic literature review summarizing risk factors, clinical presentation, laboratory diagnosis, treatment regimens and outcome of this condition.

DISCUSSION

On the basis of our study, we recommend an early diagnostic arthrocentesis of the joint for Gram stain microscopy, culture and antibiotic sensitivity testing to guide the appropriate use of antibiotics. In cases of hospital acquired infections where drug resistant Gram negative bacteria are suspected or prevalent, broad-spectrum antibiotics such as meropenem plus or minus amikacin may be given as the empirical treatment until the sensitivities are confirmed. In addition, adequate surgical joint lavage should be considered as the mainstay of treatment.

Management of septic arthritis: a systematic review

OBJECTIVE

To evaluate the existing evidence on the diagnosis and management of septic arthritis in native joints.

DESIGN

Systematic review.

DATA SOURCES

Cochrane Library, Medline, Embase, National Electronic Library for Health, reference lists, national experts.

REVIEW METHODS

Systematic review of the literature with evaluation of the methodological quality of the selected papers using defined criteria set out by the Clinical Effectiveness and Evaluation Unit of the Royal College of Physicians.

RESULTS

3291 citations were initially identified. Of these, 189 full text articles were identified for potential selection. Following review of these full text articles, 80 articles were found to fulfil the inclusion criteria and were included in the final list.

CONCLUSIONS

were drawn on the diagnosis, investigation and management of septic arthritis.

DISCUSSION

Little good quality evidence exists to guide the diagnosis and management of septic arthritis. Overall, no investigation is more reliable in the diagnosis of septic arthritis than the opinion of an experienced doctor. Aspiration and culture of synovial fluid is crucial to the diagnosis, but measurement of cell count is unhelpful. Antibiotics are clearly required for a prolonged period, but there are no data to indicate by which route or for how long. Key unanswered questions remain surrounding the medical and surgical management of the infected joint.

Advances in the Management of Septic Arthritis

Septic arthritis still continues to be a common and serious problem at major urban medical centers and is one of the most rapidly destructive forms of acute arthritis. The yearly incidence of bacterial arthritis varies from 2 to 10 per 100,000 in the general population to 30 to 70 per 100,000 in patients with rheumatoid arthritis and in patients with joint prostheses. Irreversible loss of joint function may develop in up to 50% of the patients. Despite better antimicrobial agents and improved hospital care, the fatality rate for this medical problem has not changed substantially during the past 30 years. An understanding of the risk factors and the pathogenesis of nongonoccocal bacterial arthritis and other forms of infectious arthritis, primarily in the context of a differential diagnosis and treatment, are important to avoid the delay in making a correct diagnosis and to improve the prognosis.

Septic arthritis of the shoulder, elbow, and wrist

Septic arthritis of the shoulder, elbow, or wrist is not commonly described in the literature. We evaluated the micro- biology of these infections and the diagnostic role of joint aspirate findings. This retrospective study includes 52 patients, diagnosed from 1994 to 2004, with septic arthritis of the shoulder (n = 17), elbow (n = 23), or wrist (n = 12). The mean age was 44.3 years, and 54% of patients (28/52) had comorbidities. The prevalence of Staphylococcus aureus was 76%. Ninety-six percent of aspirates with positive cultures had a polymorphonuclear differential count greater than 85% of the total aspirate white blood cell count. Staphylococcus aureus is the most prevalent organism. A high index of suspicion for septic arthritis is necessary for all patients with upper extremity joint complaints, irrespective of age and medical status. The joint aspirate differential white blood cell count may be helpful in the diagnosis.

Recalcitrant septic knee arthritis due to adjacent osteomyelitis in adults

We asked whether adjacent osteomyelitis with acute septic knee arthritis explained a lack of response to initial management, and whether patient comorbidities predisposed to the nonresponsiveness. From 147 adult patients (151 knees) with septic arthritis, we identified 29 patients (33 knees) who had persistence or recurrence of symptoms after surgical drainage. Adjacent osteomyelitis was present in 31 (94%) of the 33 knees (27 of 29 patients) with poor response to treatment. Patients with adjacent osteomyelitis had more comorbid conditions (23 of 27 patients, 85%) than patients without osteomyelitis (64 of 120, 53%). The most common comorbid conditions in patients with adjacent osteomyelitis were diabetes mellitus (10 patients, 37%) and intravenous drug use (eight patients, 30%). We identified Staphylococcus aureus in 19 of 31 knees (61%) with osteomyelitis, eight (26% of total cases) of which were methicillin-resistant. Persistence of clinical signs of infection after surgical management of septic knee arthritis in adults should raise the suspicion of adjacent osteomyelitis, especially in patients with comorbid conditions. Additional imaging studies may be necessary to evaluate the distal femur and proximal tibia.

Acute hot joint

The acute hot joint has a broad differential diagnosis. It presents to a wide spectrum of practitioners in primary and secondary care, many of whom may be unfamiliar with the management of musculoskeletal disease. This review discusses the most serious cause of the hot joint, sepsis, and discusses the other less worrying, but more frequent, diagnoses.

Septic Arthritis

Septic arthritis has increased in incidence in the United States in the past two decades, and increasingly affects an older population with a greater burden of chronic illness and a higher risk for drug-resistant organisms. Successful management depends on a high diagnostic suspicion, empiric antibiotic treatment, and joint drainage. A bacteriologic diagnosis is more likely with inoculation into blood culture bottles than plating on solid media. As MRSA increases in prevalence in the community, empiric anti-biotic regimens increasingly need to be active against MRSA.

Joint aspiration and injection

Joint aspiration/injection is an invaluable procedure for the diagnosis and treatment of joint disease. The knee is the commonest site to require aspiration although any non-axial joint is accessible for obtaining synovial fluid. Septic arthritis and crystal arthritis can be readily diagnosed by aspirating synovial fluid. Intra-articular injection of long-acting insoluble corticosteroids produces rapid resolution of inflammation in most injected joints and is a well established procedure in rheumatological practice. The technique involves only 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 a safe procedure. This chapter addresses the indications, technical principals, expected benefits and risks of intra-articular corticosteroid injection. The use of other intra-articular injections including osmic acid, radioisotopes and hyaluronic acid, which are less universally utilised than intra-articular corticosteroid, will also be addressed.

Septic arthritis in patients aged 80 and older: a comparison with younger adults

OBJECTIVES

To compare the frequency and characteristics of septic arthritis in patients younger than 80 and aged 80 and older.

DESIGN

Retrospective.

SETTING

Single hospital center.

PARTICIPANTS

Patients admitted between 1979 and 2002 for septic arthritis.

MEASUREMENTS

Age, sex, time to diagnosis, predisposing factors, joint, temperature, white blood cell count, microorganism, and short-term outcome.

RESULTS

Of 335 patients, 206 (61.4%) were aged 60 and older, and 42 (12.5%) were 80 and older. The latter had an average age of 84 (range 80-97) and were mainly women (72%). Eighteen of the 42 had at least one risk factor. The mean time to diagnosis was 21 days (range 1 day to 3 months). Twenty patients (47%) had knee involvement, six (14%) shoulder involvement, ten (23.8%) a prosthetic infection, and five (12%) polyarticular infection. Ten (23%) were afebrile. In half of the cases, there was no increase in white blood cell count. The microorganisms isolated were Staphylococcus aureus (n=16, 38%), coagulase negative staphylococci (n=8, 19%), streptococci (n=12, 28%), and gram-negative bacilli (n=6, 14%). The mortality rate increased with age: 0.7% of patients younger than 60, 4.8% of those aged 60 to 79, and 9.5% of those aged 80 and older.

CONCLUSION

Advanced age is a risk factor for septic arthritis and poor outcome.

Clinical features and aetiology of septic arthritis in northern Israel

OBJECTIVE

To assess the clinical features and determine the pathogens responsible for septic arthritis in patients admitted to two community hospitals in the Haifa district in northern Israel over a 17-yr period.

METHODS

A retrospective study of the hospital records of patients with septic arthritis admitted to Carmel Medical Center and Bnai Zion Medical Center in Haifa between 1987 and 2003.

RESULTS

Of 150 cases identified by discharge summary diagnostic codes, only 110 patients met criteria for the case definition of septic arthritis, and these form the basis of this report. Their mean age was 37.2 yr. Of the patients, 10.4% were recent immigrants, most of them from the former Soviet Union and from Ethiopia. Primary joint disease was reported in 21.8% of the cases, osteoarthritis being most prevalent (8.1%). Of the infected joints, 8.1% were prosthetic. Staphylococcus aureus was the most common pathogen isolated, making up 40% of all positive cultures. Streptococcal and Gram-negative bacilli were both identified in 14%. Eight patients had tuberculous arthritis (9%). Another pathogen, unusual in developed countries, was Brucella species, which was identified in 11% of the cases. Two-thirds of the patients underwent surgical joint drainage while the rest were treated solely with antibiotics.

CONCLUSIONS

The present study highlights the importance of characterizing the profile of species causing septic arthritis in specific regions, taking into account ethnic, genetic and environmental factors. In our survey population, tuberculous arthritis is a growing problem, mainly due to recent immigration waves, and brucella is an endemic and common pathogen. It is important to keep a high level of suspicion for these latter two bacteria, as they require special and unique care.

Daily Needle Aspiration Versus Surgical Lavage for the Treatment of Bacterial Septic Arthritis in Adults

Septic arthritis is a substantial public health problem, accounting for 0.2-0.7% of hospital admissions. However, despite the availability of effective antibiotics, the appropriate approach to adjunctive therapy remains controversial. Although early drainage is essential to minimize the risks of permanent loss of articular function, it is unclear whether the optimal approach involves arthroscopic lavage or daily arthrocentesis; surgeons appear to prefer surgical lavage because their training routinely considers septic arthritis to be a closed-space infection comparable to an abscess, whereas rheumatologists appear to prefer daily arthrocentesis because of its ease and non-invasive nature. There is a paucity of prospective data comparing the two approaches, and the literature is largely retrospective. Herein, we review the available literature concerning drainage of bacterially infected joints, and conclude that in the absence of prospective randomized clinical trials, the best evidence suggests that there is no compelling reason to recommend surgical lavage for the initial management of uncomplicated septic arthritis.

Bacterial and lyme arthritis

Septic arthritis is an infectious disease emergency, requiring aggressive joint drainage and prompt antibiotic therapy. Because age and joint damage are major risk factors, septic arthritis may become more common as the baby-boom generation reaches senescence. Bacteremic joint infections have a high mortality, and long-term disability from joint damage is common. Lyme arthritis has a negligible mortality and low morbidity but causes disproportionate popular anxiety. Most patients with Lyme arthritis respond well to oral antibiotic regimens and recover completely. A few patients develop antibiotic-resistant Lyme arthritis, which is probably autoimmune in nature and responds to immunosuppressive therapy. This paper reviews the presentation, diagnosis, and management of bacterial and Lyme arthritis. Septic arthritis caused by Streptococcus pneumoniae and group B streptococci may be increasing in prevalence. Prospective studies are required to determine whether there is any benefit of surgical or arthroscopic joint drainage in septic arthritis, compared with serial arthrocentesis, and to determine the role of corticosteroid therapy in septic arthritis in adults, if any.

Streptococcal septic arthritis in adults. A study of 55 cases with a literature review

OBJECTIVES

To evaluate the rate of occurrence and characteristics of streptococcal septic arthritis.

METHODS

Retrospective single-center study of patients with bacteriologically documented septic arthritis admitted to a rheumatology department over a 20-year period.

RESULTS

Of 303 cases of septic arthritis, 55 (18%) were due to streptococci and 166 (55%) to Staphylococcus aureus (55%). As compared to patients with S. aureus arthritis, patients with streptococcal arthritis was more likely to be in female (56% vs. 36%, P < 0.006) and older than 60 years of age (71% vs. 58%), less likely to have comorbidities (36% vs. 56%), rheumatoid arthritis (5% vs. 19%, P < 0.01), or diabetes (2% vs. 15%, P < 0.01), and more likely to have cancer (13% vs. 7%). Involved joints and proportions of patients with arthritis in multiple joints were similar in two groups. Mortality was lower in the group with streptococcal infection (3.6% vs. 7.8%). The streptococci were distributed as follows: group A (n = 7), group B (n = 12), group C (n = 4), group D (n = 7), group F (n = 1), group G (n = 2), nongroupable (n = 14), nontypable (n = 1), and Streptococcus pneumoniae (n = 7). Groups A and B and nongroupable strains mainly affected women; group A selectively involved younger patients and group B very elderly patients. Comorbidity, most notably cancer, was common in patients with S. pneumoniae or group D streptococci. The portal of entry was often a skin lesion for groups A and B and a medical procedure for group D. Multiple joint involvement was common with groups A and B and prosthetic joint infection with groups B and C. Group A and S. pneumoniae were associated with severe systemic symptoms and extra articular foci of infection, whereas a smoldering course was more common with groups D and G and with nongroupable strains. Residual joint abnormalities were noted in half the patients, with no differences across groups.

CONCLUSIONS

The features of streptococcal septic arthritis vary according to the group of the causative organism and differ from those of S. aureus arthritis.

Sternoclavicular septic arthritis: review of 180 cases

We review 170 previously reported cases of sternoclavicular septic arthritis, and report 10 new cases. The mean age of patients was 45 years; 73% were male. Patients presented with chest pain (78%) and shoulder pain (24%) after a median duration of symptoms of 14 days. Only 65% were febrile. Bacteremia was present in 62%. Common risk factors included intravenous drug use (21%), distant site of infection (15%), diabetes mellitus (13%), trauma (12%), and infected central venous line (9%). No risk factor was found in 23%. Serious complications such as osteomyelitis (55%), chest wall abscess or phlegmon (25%), and mediastinitis (13%) were common. Staphylococcus aureus was responsible for 49% of cases, and is now the major cause of sternoclavicular septic arthritis in intravenous drug users. Pseudomonas aeruginosa infection in injection drug users declined dramatically with the end of an epidemic of pentazocine abuse in the 1980s. Sternoclavicular septic arthritis accounts for 1% of septic arthritis in the general population, but 17% in intravenous drug users, for unclear reasons. Bacteria may enter the sternoclavicular joint from the adjacent valves of the subclavian vein after injection of contaminated drugs into the upper extremity, or the joint may become infected after attempted drug injection between the heads of the sternocleidomastoid muscle. Computed tomography or magnetic resonance imaging should be obtained routinely to assess for the presence of chest wall phlegmon, retrosternal abscess, or mediastinitis. If present, en-bloc resection of the sternoclavicular joint is indicated, possibly with ipsilateral pectoralis major muscle flap. Empiric antibiotic therapy may need to cover methicillin-resistant Staphylococcus aureus (MRSA).

Septic arthritis of the pubic symphysis: review of 100 cases

We report a novel case of septic arthritis of the symphysis pubis due to Streptococcus pneumoniae and review 99 previously reported cases of infection of this joint. Typical features of pubic symphysis infection included fever (74%), pubic pain (68%), painful or waddling gait (59%), pain with hip motion (45%), and groin pain (41%). Risk factors included female incontinence surgery (24%); sports, especially soccer (19%); pelvic malignancy (17%); and intravenous drug use (15%). Septic arthritis of the pubic symphysis is often misdiagnosed as osteitis pubis, a sterile inflammatory condition. Causative organisms differed according to risk factors. Staphylococcus aureus was the major cause among athletes, Pseudomonas aeruginosa among intravenous drug users, and infections among patients with pelvic malignancies were usually polymicrobial, involving fecal flora. Patients with recent urinary incontinence surgery usually had monomicrobial infection, with no predominant pathogen. Since osteomyelitis is present in 97% of patients, we recommend antibiotic courses of 6 weeks' duration. Surgical debridement is required in 55% of patients.

Prospective comparative study of patients with culture proven and high suspicion of adult onset septic arthritis

OBJECTIVE

To investigate whether patients with acute septic arthritis (SA) diagnosed by positive synovial fluid (SF) culture (Newman grade A) have different clinical and serological features from those with sterile SF in whom there is nonetheless a high suspicion of SA (Newman grades B and C).

PATIENTS AND METHODS

A prospective 12 month multicentre hospital based study of adult patients with SA recruited 47 patients with culture positive SA and 35 patients with clinically suspected SA but sterile SF.

RESULTS

Patient demography, clinical and laboratory features at presentation were similar irrespective of the underlying diagnosis, SF culture, and the presence of prosthetic joints. Medical and surgical treatment and outcome were comparable in the two patient groups. Patients with both suspected and proven SA were more likely to be from the more socially deprived areas of our community (p<0.0001).

CONCLUSION

Patients in whom there is a high clinical suspicion of SA are comparable to those patients with SA with a positive SF culture and have similar morbidity and mortality on follow up. Therefore, if clinical suspicion of SA is high then it is correct to treat as SA in the absence of bacterial proof.

Pneumococcal septic arthritis: review of 190 cases

This article reports 13 cases of pneumococcal septic arthritis and reviews another 177 cases reported since 1965. Of 2407 cases of septic arthritis from large series, 156 (6%) were caused by Streptococcus pneumoniae. Mortality was 19% among adults and 0% among children. Pneumococcal bacteremia was the strongest predictor of mortality. At least 1 knee was involved in 56% of adults. Polyarticular disease (36%) and bacteremia (72%) were more common among adults with septic arthritis caused by S. pneumoniae than among adults with other causative organisms. Only 50% of adults with pneumococcal septic arthritis had another focus of pneumococcal infection, such as pneumonia. Functional outcomes were good in 95% of patients. Uncomplicated pneumococcal septic arthritis can be managed with arthrocentesis and 4 weeks of antibiotic therapy; most cases of pneumococcal prosthetic joint infection can be managed without prosthesis removal. A fatal case of septic arthritis caused by a beta-lactam-resistant strain of S. pneumoniae is also presented.

Arthritis in the intensive care unit

Acute arthritis in critically ill patients may be caused by local or systemic infection, by a flare of chronic joint disease such as rheumatoid or crystal-associated arthritis, or by less common entities such as hemarthrosis. Diagnosis requires analysis of synovial fluid, and appropriate treatment is based on its findings. Prompt diagnosis and treatment are usually necessary to prevent the significant morbidity associated with these conditions.

The value of synovial fluid assays in the diagnosis of joint disease: a literature survey

OBJECTIVE

To carry out a critical appraisal of the literature in an attempt to assess the current value of synovial fluid (SF) analysis in the diagnosis of joint disease.

METHODS

A literature search was undertaken using the Medline, Biomed, Bids, Pubmed, and Embase electronic databases using the keywords: synovial fluid (SF) analysis, SF crystals, joint sepsis, acute arthritis, and SF cell counts, cytology, biomarkers, and microbiology.

RESULTS

Publications fell into three main categories. Firstly, reports assessing the value of the three traditional assays (microbiology, white blood cell counts, and microscopy for pathogenic crystals). For these quality control evidence was found to be sparse, and tests for sensitivity, specificity, and reliability showed worrying variations. These poor standards in SF analysis may be due to lack of inclusion of some tests within routine pathology services. Secondly, claims for the usefulness of "new" assays (cytology and biochemical markers). For cytology, the supporting evidence was mainly anecdotal and there were no reports on specificity, sensitivity, and reliability. Interpretation difficulties are a major hindrance to the clinical use of biochemical assays, which remain primarily research tools. Finally, work on the diagnostic value of SF analysis in general. The appraisal confirmed that SF analysis remains of major diagnostic value in acute arthritis, where septic arthritis or crystal arthropathy is suspected, and in intercritical gout.

CONCLUSIONS

Given the importance of SF tests, rationalisation of their use, together with improved quality control, should be immediate priorities. Further investigation is recommended into the contribution of SF inspection and white cell counts to diagnosis, as well as of the specificity and sensitivity of SF microbiological assays, crystal identification, and cytology.

A prospective 2-year study of 75 patients with adult-onset septic arthritis

AIMS AND METHODS

To assess the clinical features of septic arthritis and characterize therapeutic strategies and outcome in a prospective study of 75 patients selected by positive synovial fluid culture.

RESULTS

Underlying joint disease was present in 46 patients, 25 of whom had rheumatoid arthritis and 15 osteoarthritis. Eleven patients were i.v. drug abusers. Fifty-six per cent of cases involved the knee, 15% involved two or more joints, and staphylococci and streptococci were cultured in >90%. Seventy-eight per cent of patients lived in areas of high social deprivation. Fever was present in 64% and the white cell count (WCC) was normal in 38%. The C-reactive protein was elevated in 98%. Leg ulcers were present in 11% of all patients but in 38% of patients who died (P<0.006). Median duration of antibiotic therapy was 15 days i.v. with subsequent oral treatment for 21 days. Thirty-seven per cent of cases required surgical intervention. Mortality was 11%. A raised WCC at presentation (P<0.02) and the development of abnormal renal function (P<0.015) were predictors of poor prognosis.

Pyarthrosis in patients with rheumatoid arthritis: a detailed analysis of 10 cases and literature review

OBJECTIVES

1) To analyze the clinical features and outcome of patients with rheumatoid arthritis and pyarthrosis seen in a rheumatology department during a 9-year period; 2) To review the available literature about this association in the last decade.

METHODS

From the database of our department, we collected all hospitalized cases of infectious arthritis in native joints between January 1990 and December 1998. In 10 cases (27%), pyarthrosis occurred in patients with rheumatoid arthritis. A detailed analysis of each patient was performed. The literature was reviewed by using MEDLINE from 1990 to 1999.

RESULTS

The mean age of patients was 63.2 years; six were female. Most patients had long-standing disease and poor functional class, and all received glucocorticoid treatment. Mean diagnostic delay was 7.3 days. Causative organisms were Staphylococcus aureus (4 cases), gram-negative bacilli (3 cases), anaerobic bacteria (2 cases), and Streptococcus pneumoniae (n = 1). Two patients died. In all but two patients who survived, joint function worsened.

CONCLUSIONS

Rheumatoid arthritis is a relevant host-related risk factor for septic arthritis. Pyarthrosis in these patients is associated with considerable morbidity and mortality.

Prevention of diseases caused by Staphylococcus aureus using the peptide RIP

Staphylococcus aureus causes many diseases including cellulitis, keratitis, osteomyelitis, septic arthritis and mastitis. The heptapeptide RIP has been shown to prevent cellulitis in mice, which was induced by S. aureus strain Smith diffuse. Here we show that RIP can also significantly reduce the overall pathology and delay the onset of disease symptoms in several other models of S. aureus infections, including: keratitis (tested in rabbits against S. aureus 8325-4), osteomyelitis (tested in rabbits against S. aureus MS), mastitis (tested in cows against S. aureus Newbould 305, AE-1, and environmental infections) and septic arthritis (tested in mice against S. aureus LS-1). These findings substantiate that RIP is not strain specific in its inhibitory activity and that RIP is an effective inhibitor of bacterial pathology at multiple body sites following diverse routes and doses of administration. These findings strongly evidence the potential value of RIP as a chemotherapeutic agent.

Septic arthritis due to Streptococcus pneumoniae in Nottingham, United Kingdom, 1985-1998

Pneumonia and meningitis are the 2 most frequent manifestations of Streptococcus neumoniae infection. Pneumococcal septic arthritis is considered to be relatively uncommon. Between 1985 and 1998, 32 (8. 2%) of 389 cases of septic arthritis seen in the 2 hospitals in Nottingham, United Kingdom, were due to S. pneumoniae. Six of 7 children with pneumococcal septic arthritis were aged <2 years. Of the 25 adults, 20 (80%) were aged >60 years, 11 (44%) had concomitant pneumococcal infection elsewhere, and 23 (92%) had articular or nonarticular diseases and/or other risk factors. In the elderly, a lack of febrile response was striking. S. pneumoniae was isolated from blood and joint cultures in >70% of cases, and gram-positive diplococci were seen in the joint fluids of 90% of patients. The mean duration of antimicrobial therapy for adults was twice as long as that for children. Eight (32%) of the adults died.