6Septic arthritis
Section snippets
Epidemiology
Information concerning the epidemiology of septic arthritis is limited because of several factors. Acute septic arthritis is an uncommon disease; therefore, few reports of series containing more than 50 cases have been published, and most of the published reports are from retrospective cohorts [2]. Moreover, the case definitions employed have, in general, restricted these studies to the investigation of bacteriologically confirmed cases.
The overall estimated incidence of septic arthritis in
Microbiology
The causative organisms responsible for septic arthritis vary with the age of the patient. In all ages and risk groups, with the exception of children younger than 2 years, the most frequent organism is Staphylococcus aureus, which is isolated in 37–56% of cases [12], *[13]. In recent times, an increase in methicillin-resistant S. aureus (MRSA) infections has been reported in several health-care systems, particularly in the elderly and intravenous drug abuser populations as well as associated
Pathogenesis
A joint becomes infected when an infectious agent enters the synovium. The main routes by which pathogens accumulate in the joints are the following: (a) haematogenously, with the consequent lodging of the pathogen in synovial capillaries; (b) infected contiguous foci; (c) neighbouring soft-tissue sepsis; and (d) by direct inoculation due to trauma or an iatrogenic event, such as diagnostic or therapeutic arthrocentesis or joint surgery.
The synovium is a well-vascularised structure with no
Predisposing factors
Although septic arthritis can affect people at any age, elderly patients (especially those older than 80 years) and very young children are more frequently affected [3].
Underlying joint diseases, such as rheumatoid arthritis (RA), osteoarthritis, crystal arthropathies and other forms of inflammatory arthritides, are predisposing factors for the development of infectious arthritis. [3] In particular, patients with RA have an approximately 10-fold-higher incidence of septic arthritis than the
Clinical features
Patients with acute septic arthritis typically present with a 1–2-week history of malaise, erythema, swelling, tenderness and a decreased range of motion affecting a single joint [29], although these symptoms may not always be present [38]. The onset of fever, which in most cases is mild and with only 30–40% of individuals having a temperature >39 °C, is a typical characteristic [39].
Septic arthritis is usually monoarticular; however, the possibility of polyarticular septic arthritis should be
Diagnosis
The definitive diagnosis of septic arthritis is made by direct demonstration of bacteria in the SF or after culture of the pathogen. The diagnosis is based, in most cases, on clinical symptoms and a detailed history, a careful examination and test results [46]. It has been suggested that a careful examination by an experienced clinician is of utmost importance when making a rapid diagnosis of septic arthritis [47].
Prognosis
Mortality reported from septic arthritis varies in different studies, but it appears to be approximately 11% for monoarticular arthritis [1]. The risk of permanent loss of joint function is nearly 40% [6].Delayed diagnosis, advanced age, underlying joint diseases and the presence of synthetic material within the joint are conditions associated with a poor prognosis. Delaying treatment for as little as 7 days can result in poor outcomes [19]. High mortality (19–33%) in elderly patients is
Management
The mainstay of treatment involves prompt debridement for removal of purulent material and early treatment with antibiotics [1].
Evidence concerning the choice and duration of antibiotic treatment is sparse because no randomised controlled trials have been conducted so far. Early antibiotic treatment should be based on clinical presentation, patient history, organisms likely to be involved and Gram-staining results *[39], *[47]. In view of the fact that the most frequent pathogens are S. aureus
A special condition: prosthetic joint infections
Prosthetic joints provide a physiological niche for microorganisms and may become a site of infection. Infections associated with prosthetic joints can represent a devastating complication of joint replacement procedures [71].
In patients with primary joint replacement, the infection rate in the first 2 years is <1% in the hip and shoulder joints, <2% in the knees and <9% in the elbows [72].
Prosthetic implants are often coated with host proteins, usually fibronectin and fibrinogen, shortly after
Gonococcal arthritis
Gonococcal arthritis is the result of infection with N. gonorrhoeae acquired from a primary sexually transmitted mucosal infection. Gonococci may infect mucosal surfaces such as the urethra, endocervix, pharynx, rectum and cervico-vaginal mucosa. In a minority of patients, especially in those untreated, the infection can progress to induce endometriosis, salpingitis, prostatitis, dermatitis, arthritis and disseminated gonococcal infection (DGI).
Conclusion
Septic arthritis can result in irreversible joint destruction. The main factors for avoiding severe outcomes are an early, prompt and effective treatment, using both appropriate antibiotics and joint lavage. In acute joint disease, with one or more swollen, hot and painful joints, septic arthritis should be suspected. The definitive diagnosis of septic arthritis is made by direct demonstration of bacteria in the SF or after culturing the pathogen. However, there is little quality evidence to
Conflict of interest
These authors have no conflicts of interest to declare.
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