From the Guidelines
Septic arthritis is a medical emergency that requires immediate attention, and the most recent evidence suggests that prompt joint fluid aspiration and intravenous antibiotics, such as vancomycin and ceftriaxone, are crucial for treatment, as stated in the 2022 study by the Journal of the American College of Radiology 1.
Definition and Symptoms
Septic arthritis is a serious joint infection that occurs when bacteria, fungi, or other microorganisms invade a joint space, causing inflammation, pain, and potential joint damage. Common symptoms include:
- Severe joint pain
- Swelling
- Warmth
- Redness
- Fever
- Limited range of motion The knee is most commonly affected, though any joint can be involved.
Diagnosis
Diagnosis typically involves joint fluid aspiration (arthrocentesis) to analyze for white blood cell count, crystals, and culture to identify the causative organism. The Kocher criteria, which include fever, erythrocyte sedimentation rate, white blood cell count, and an inability to bear weight on the affected side, can help distinguish septic arthritis from transient synovitis 1.
Treatment
Treatment consists of immediate intravenous antibiotics, often starting with empiric therapy such as vancomycin 15-20 mg/kg IV every 12 hours plus ceftriaxone 2g IV daily while awaiting culture results, then narrowing to targeted antibiotics based on the identified organism. Surgical drainage (arthroscopy or open debridement) is often necessary, especially for larger joints, as recommended by the Infectious Diseases Society of America 1. Antibiotic therapy typically continues for 2-6 weeks, with transition to oral antibiotics once clinical improvement occurs. Staphylococcus aureus is the most common causative organism in adults, while children may have different pathogens based on age.
Risk Factors and Complications
Risk factors include recent joint surgery, immunocompromised states, intravenous drug use, and pre-existing joint disease. Without prompt treatment, septic arthritis can lead to permanent joint damage, osteomyelitis, or systemic infection, making early recognition and aggressive management essential for preserving joint function, as highlighted in the 2022 study by the Journal of the American College of Radiology 1.
From the Research
Definition and Overview
- Septic arthritis is an acute onset of monoarticular inflammation of a joint due to an infectious etiology, usually bacterial but can be viral or fungal 2.
- It is a medical emergency that can lead to significant morbidity and mortality if not promptly diagnosed and treated 3, 4, 5, 6.
Risk Factors
- Risk factors for septic arthritis include age older than 80 years, diabetes mellitus, rheumatoid arthritis, recent joint surgery, hip or knee prosthesis, skin infection, and immunosuppressive medication use 3.
- Other risk factors include smoking, comorbid conditions (eg, HIV infection, osteoarthritis), and other factors (eg, previous intra-articular injection) 2.
Clinical Presentation and Diagnosis
- The clinical presentation of septic arthritis can overlap with those of many other joint conditions, making diagnosis challenging 2.
- Physical examination findings and serum markers, including erythrocyte sedimentation rate and C-reactive protein, are helpful in the diagnosis but are nonspecific 3.
- Synovial fluid studies are required to confirm the diagnosis, and history and Gram stain aid in determining initial antibiotic selection 3, 6.
Treatment and Management
- Management involves a combination of medical and surgical treatments tailored to infection severity, causative pathogens, and overall patient condition 2.
- Empiric antibiotic therapy should be initiated if there is clinical concern for septic arthritis, and oral antibiotics can be given in most cases because they are not inferior to intravenous therapy 3.
- Total duration of therapy ranges from two to six weeks; however, certain infections require longer courses 3.
- Surgical treatment may be required in approximately 30% of patients with septic arthritis 2.