Key Points
- Use the highest‑yield diagnostic test early; do not let testing delay time‑critical therapy.
- Set objective targets (hemodynamic, neurologic, respiratory) and reassess frequently.
- Plan definitive source control or reperfusion when indicated; document follow‑up and patient education.
Algorithm
- Perform urgent arthrocentesis; send synovial fluid for cell count, Gram stain, culture, and crystals.
- Start empiric antibiotics targeting MRSA and gram-negative organisms based on risk; adjust to culture/MIC.
- Drain joint: needle aspiration vs arthroscopic/open washout for hip/shoulder or poor response.
- Early mobilization with PT after initial control; monitor CRP and clinical course to guide duration.
Clinical Synopsis & Reasoning
Acute monoarthritis with fever and elevated inflammatory markers warrants urgent arthrocentesis. Start empiric IV antibiotics after cultures and arrange operative washout for large joints or if poor response to needle drainage.
Treatment Strategy & Disposition
Stabilize ABCs. Initiate guideline‑concordant first‑line therapy with precise dosing and continuous monitoring. Escalate to advanced or procedural interventions based on explicit failure criteria. Define ICU, step‑down, and ward disposition triggers; involve specialty teams early.
Epidemiology / Risk Factors
- Risk varies by comorbidity and precipitants; see citations for condition‑specific data.
Investigations
| Test | Role / Rationale | Typical Findings | Notes |
|---|---|---|---|
| Synovial fluid analysis | Diagnosis | WBC often >50k with PMN predominance | Gram stain/culture/crystals |
| Blood cultures | Pathogen ID | Often positive | Draw before antibiotics |
| Imaging (US/MRI) | Effusion/osteomyelitis | Joint effusion, soft tissue edema | Guide drainage |
Pharmacology
| Medication/Intervention | Mechanism | Onset | Role in Therapy | Limitations |
|---|---|---|---|---|
| Vancomycin IV | MRSA coverage | Hours | Empiric gram-positive coverage | TDM/AUC monitoring |
| Ceftriaxone IV (or cefepime if risk) | Gram-negative coverage | Hours | Add for gonorrhea/enterics | Tailor to cultures |
| Duration 2–4 weeks (IV → PO) | Therapy plan | Days-weeks | Based on organism and response | Longer for complicated cases |
Prognosis / Complications
- Outcome depends on timeliness of diagnosis and definitive therapy; monitor for complications.
Patient Education / Counseling
- Provide red‑flag education, adherence guidance, and explicit return precautions; arrange timely specialty follow‑up.
References
- SANJO Guideline (2023): Septic Arthritis in Native Joints — Link