Approach
All patients with suspected septic arthritis should be started on empirical antibiotic therapy. There is no good-quality evidence upon which to base decisions of antibiotic choice, duration of therapy, or route of administration of therapy. Antibiotics are often given intravenously for 2 weeks, followed by a further 4 weeks of oral therapy. There is limited evidence indicating that it may be safe to reduce the duration of intravenous antibiotics and/or the overall duration of antibiotics in carefully selected patients.[34][35] Local guidance and/or expert opinion should always be consulted.
Local infectious disease services should be consulted regarding prevalent organisms and their sensitivities.[12] The choice of antibiotic therapy varies worldwide and should be modified in light of this and the results obtained from subsequent Gram stain and culture.
Affected joints should be aspirated to dryness as often as is required. This can be done either through closed-needle aspiration or arthroscopically. There is no evidence to suggest that either of these approaches is superior to the other, except in the case of suspected hip sepsis, where early referral to an orthopedic surgeon is recommended, as urgent open debridement may be required.
How to aspirate synovial fluid from the knee and administer intra-articular medication using a medial approach.
How to aspirate synovial fluid from the shoulder and administer intra-articular medication. Video demonstrates a posterior approach to the glenohumeral joint and a lateral approach to the subacromial space.
In patients with inflammatory arthritis who are on biological therapies, such as tumor necrosis factor-alpha inhibitor therapy, current recommendations are that these therapies should be discontinued for 12 months after an episode of joint sepsis and indefinitely if an infected prosthetic joint remains in situ.[36]
Hip sepsis
Owing to the technical difficulty with attempting closed-needle aspiration of a hip joint, it is suggested that patients with hip sepsis are referred as a matter of urgency to an orthopedic surgeon as they may require arthroscopic aspiration and drainage. Aspiration may need to be done under ultrasound guidance.
These patients should otherwise be investigated in the same way as other patient groups, and empirical antibiotic therapy should be instituted after cultures have been taken.
Suspected streptococci or staphylococci
Gram-positive bacteria are the commonest infecting organisms and should be suspected if there are no factors to suggest an alternative etiology.[11] Empirical treatment is recommended with vancomycin. In patients who are allergic to vancomycin, clindamycin or a third-generation cephalosporin may be used.[12] Treatment of confirmed infection should be guided by antibiotic sensitivities. Intravenous therapy with oxacillin, with or without gentamicin, is one possible regimen. Clindamycin or a third-generation cephalosporin may be used in penicillin-allergic patients. Oral dicloxacillin, clindamycin, or cephalexin may be used after intravenous antibiotics are ceased.
The following patients are at risk for MRSA:
Recent inpatients
Nursing home residents
Patients with leg ulcers or urinary catheters.
Advice from an infectious diseases specialist should be sought. Empirical treatment is recommended with vancomycin,[12] followed by oral clindamycin or linezolid. In regions where MRSA is common as a cause of septic arthritis, including the US, initial antibiotic regimens for all patients should generally include an antibiotic active against MRSA (e.g., vancomycin).[10]
Suspected gram-negative infection
The following patients are at high risk for gram-negative infection:
Older or frail patients
Patients with recurrent urinary tract infections
Patients who have had recent abdominal surgery.
In this group empirical treatment is recommended with a third-generation cephalosporin (e.g., ceftriaxone, ceftazidime, or cefotaxime). In patients in whom Pseudomonas infection is suspected (e.g., intravenous drug users), ceftazidime should be preferred. Local policy may be to add gentamicin, particularly in patients with sepsis. In those patients who are cephalosporin-allergic, ciprofloxacin is recommended. In patients with confirmed gram-negative infection, intravenous antibiotics are usually followed by a course of oral antibiotics (e.g., with cephalexin). Choice of antibiotics should be guided by culture sensitivities.
The treatment of patients who are penicillin- or cephalosporin-allergic should be discussed with an infectious disease specialist.[12]
Gonococci or meningococci
Empirical treatment should be with ceftriaxone or similar, dependent on local policy and sensitivities. Intravenous antibiotics are usually followed by a course of oral antibiotics.
Other organisms
For patients with septic arthritis caused by other organisms (e.g., fungi, tuberculosis), the advice of an infectious diseases specialist should be sought.
Intravenous drug users and intensive care unit patients
For intensive care unit patients, patients with known colonization of other organs (e.g., in cystic fibrosis), and intravenous drug users with suspected septic arthritis, the advice of an infectious disease specialist should be sought before initiating therapy, as there may be local variations in pathogenic organisms and their sensitivities.
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