Infectious arthritis

Arthroscopic debridement for septic arthritis of the shoulder joint: post-infectious arthritis is an inevitable consequence?

PURPOSE

The purpose of this study was to compare clinical outcomes and development of post-infectious arthritis of the shoulder joint after single (Group S) or repeated (Group R) arthroscopic debridement surgeries. We hypothesized that (1) repeated surgeries might be attributable to initial subchondral involvement resulting from septic arthritis and (2) the repeated surgery group would exhibit a higher incidence of post-infectious arthritic changes and inferior clinical outcomes due to prolonged resolution of the infection.

METHODS

This study included 42 patients (single surgery, n = 29; repeated surgery, n = 13) who underwent arthroscopic debridement for septic arthritis and had a minimum of 2 years of postoperative follow-up data. All patients underwent preoperative magnetic resonance imaging (MRI) with gadolinium enhancement to evaluate subchondral bone involvement suspicious for osteomyelitis secondary to septic arthritis and extension of infection around the glenohumeral joint. Functional and radiological outcomes were assessed.

RESULTS

Group S experienced a shorter duration (25.4 days) of infection than Group R (39.7 days) (p = 0.002). Increased signal intensity in the subchondral bone on preoperative MRI was identified in 9 patients (31%) in Group S and 5 patients (38%) in Group R. Post-infectious arthritic changes developed in 6 (21%) and 5 (38%) in Groups S and R, respectively. However, there were no significant differences between groups. At the final follow-up, there were no significant differences in functional assessments.

CONCLUSION

Despite a prolonged period of infection in the repeated surgery group, there was no significant difference in development of post-infectious arthritic changes or clinical outcomes in patients requiring single or repeated surgeries.

LEVEL OF EVIDENCE

Retrospective comparative study, III.

[Microbiological diagnosis of periprosthetic joint infections]

BACKGROUND

Prosthetic joint infection is a rare but serious complication after arthroplasty, leading to prolonged hospitalization and repeated surgical intervention.

THEME

In this article, successful strategies for the rapid and accurate microbiological diagnosis of infection are reviewed. In the case of clinical suspicion of a prosthetic joint infection, at least a comprehensive clinical review of the patient's postoperative history, a physical examination, routine blood tests including white cell count, erythrocyte sedimentation rate, and C-reactive protein, and further investigation of the synovial-fluid leukocyte count and microbial culture are needed. Depending of the clinical signs of infection additional blood culture samples should be taken.

RESULTS

The gold standard to confirm infection is a surgical procedure with at least 5-6 biopsies from suspected areas for both microbial culture and histopathological examination. Culture results may be negative because of previous antimicrobial therapy, a low number of culturable organisms in biofilm formations, inappropriate culture medium, and prolonged transport time.

CONCLUSION

In any of these conditions, diagnosis with highly sensitive diagnostic techniques such as polymerase chain reaction should be considered for the identification of the causative agent in order to establish the most appropriate antimicrobial treatment options.

Acute tropical polyarthritis in Zimbabwe: a prospective search for a gonococcal aetiology

Fifteen consecutive patients with acute arthritis were studied. Careful culture and microscopy of swabs from mucosal sites were performed to examine the hypothesis that the acute tropical polyarthritis commonly seen in Zimbabwe is due to undiagnosed gonococcal infection. Rheumatic fever and Reiter's disease accounted for two cases each. Gram negative intracellular diplococci were found in three patients who would otherwise have been diagnosed as having tropical polyarthritis. Except for two of the remaining eight patients, who had raised anti-streptolysin O titres suggesting recent streptococcal infection, no explanation for the arthritis was found. The clinical entity of tropical polyarthritis may not be due to a single aetiological agent.

Computed tomography of septic joints

Twenty-six patients with suspected or known septic joints who had been studied by computed tomography were retrospectively reviewed. Eighteen patients (20 joints) proved to have septic arthritis. Computed tomography was advantageous in patients with acute septic arthritis of deep-seated axial joints, such as the hip and sacroiliac, where it demonstrated particular soft tissue swelling as early as 36 hours after the onset of symptoms. In three patients, this finding on computed tomography was helpful in accurately localizing the disease process and facilitating a diagnostic closed needle aspiration biopsy procedure. Four patients had a primary osseous focus of infection in an adjacent epiphyseal region that was documented by computed tomography. Computed tomography was superior to conventional radiology in revealing early articular bone erosion in joints with curved and overlapping articular surfaces in five patients, and resulted in alteration of their treatment. Fat-fluid levels within the suprapatellar bursae were noted in one patient (two joints). Computed tomography is a valuable modality for evaluation of patients with suspected septic arthritis of axial joints, particularly in the acute stage. Furthermore, it is helpful for evaluation of possible periarticular abscess formation and can serve as a guide for a percutaneous drainage procedure. Computed tomography can also be used when articular bone erosion or medullary extension of osteomyelitis is suspected but not fully documented by conventional radiography.

Association of parvoviruses with rheumatoid arthritis of humans

A small virus resembling parvoviruses in its morphological and physicochemical properties was derived from synovial tissue of a patient with severe rheumatoid arthritis. This virus, designated RA-1, elicits a syndrome in neonatal mice that includes neurological disturbances, permanent crippling of limbs, dwarfism, alopecia, blepharitis, "masking," and a rigid curvature of the thoracic spine. Polyclonal antibodies against RA-1 display high virus neutralizing activity and in immunoassays detect reactive antigen in synovial cells from different rheumatoid arthritis patients but not persons with osteoarthritis. Putative parvoviruses isolated from several other rheumatoid arthritis patients are only weakly pathogenic for newborn mice but can generate RA-1 virus-specific antigens in tissues of these animals. It has not been established that RA-1 and existing parvoviruses of mammalian species are related.

Group B streptococcal arthritis in adults

Group B streptococcal arthritis in adults is uncommon. This report describes seven cases seen at these institutions over the past five years and reviews the previous 17 documented cases. Of seven adults, three were diabetics, three had prosthetic hips, and one had undergone splenectomy. Six had undergone no prior dental, genitourinary, or gastrointestinal procedures. The most common clinical presentation was fever and acute joint pain. Five patients had monoarticular arthritis; two had multiple joint involvement. Underlying joint abnormalities included osteoarthritis (two), prosthetic hip (three), and neuropathic joint (one). Bacteremia was documented in three and suspected in the remaining four patients, often without a primary source. Therapy included parenteral antibiotics, usually penicillin G, and drainage of the involved joint. Two of three patients with prosthetic implants required Girdlestone procedures; the third was apparently cured. The three diabetic patients died, one with resolution of group B streptococcal arthritis. The seventh patient was cured. Group B streptococcal arthritis is a serious infection in adults with diabetes and late prosthetic hip infections.

Concentrations of some antibiotics in synovial fluid after oral administration, with special reference to antistaphylococcal activity

One of 4 antibiotics with antistaphylococcal activity was given in a conventional oral dose for one day to each of 20 hospitalised patients with synovial effusion of a knee joint requiring aspiration. Serial synchronous samples of serum and synovial fluid (SF) were taken over 36 hours through indwelling cannulae. No morbidity was experienced either during or after this procedure. Satisfactory antistaphylococcal concentrations in SF were achieved with sodium fusidate (500 mg 8 hourly) and amoxycillin (250 mg 8 hourly). Cephradine (500 mg 6 hourly) frequently failed to reach the minimum inhibitory concentration for Staphylococcus aureus in the SF, and flucloxacillin (250 mg 6 hourly) was unpredictable in its penetration of the synovial space. Wide interpatient variation of both serum and SF concentrations was found. Our results indicate that sodium fusidate is an appropriate early treatment for a nonresistant staphylococcal joint infection. Amoxycillin is a suitable alternative or second antistaphylococcal drug and would also be appropriate initial therapy when the infecting organism is unknown. We strongly recommend that SF antibiotic concentrations be measured, to ensure adequate penetration of the synovial cavity, in the treatment of septic arthritis.

Treatment of Nongonococcal bacterial septic arthritis

Septic arthritis carries significant morbidity and mortality, necessitating prompt, appropriate therapy with joint fluid aspiration, intravenous antibiotics, and occasionally, surgical intervention. The initial choice of antimicrobial agent is guided by the results of synovial fluid gram stain, by identification of the pathogenesis of the primary focus, or by epidemiologic factors. Adequacy of therapy is assessed by serial synovial fluid white blood cell counts and by determining antimicrobial concentrations in the joint space. The goal of treatment is a clinically normal and sterile joint. Factors that may affect antimicrobial joint penetration include the degree of joint tissue inflammation, the degree of drug protein binding, and the chemical characteristics of the drug. Perhaps most important in determining the extent of joint penetration are factors that may affect serum antibiotic concentrations, for example, dose, route of administration, volume of distribution, but rate of elimination.

Acute nongonococcal infectious arthritis. Evaluation of risk factors, therapy, and outcome

A retrospective analysis of 71 nongonococcal joint infections in 63 patients is reported. Staphylococcus aureus was isolated from 59% of the patients. Five patients died as a result of infections. The outcome in Gram-negative joint infections was similar to the overall outcome in the entire series of patients. All 11 joints with infected prostheses ultimately required removal of the prostheses. All patients were treated with appropriate parenteral antibiotics, and surgical intervention was used in 40 joints. Six patients underwent surgical treatment because of inability to sterilize the joint with antibiotics and because of repeated joint aspirations. The outcome with surgical intervention was good only in patients younger than 16 years of ages. Medical therapy (parenteral antibiotics and frequent joint aspirations) led to good results in 74% of the patients. Outcome of joint infection was also influenced by factors which contribute to impaired host resistance.

The infectious etiology of rheumatoid arthritis. New considerations

Several possible mechanisms of chronic inflammatory arthritis that might be initiated by infectious agents are discussed. Some recent information on mycoplasma infections, long-term virus infections, and shed bacterial components provides the bases for new experimental approaches. Currently, evidence of involvement of mycoplasma or viral agents in rheumatoid arthritis is tenuous. Chronic peptidoglycan-immune-complex formation is a consideration that has been discussed, but only recently pursued in depth. It may well be that experimental studies on the infectious etiology of rheumatoid arthritis will be revitalized through an appreciation of the bacterial antigen load in the gastrointestinal tract. The perimental vehicles for testing this possibility are available and should be directly applicable at the clinical level.