## **Core Concept**
The patient's presentation suggests septic arthritis, a medical emergency characterized by infection within a joint space. This condition can lead to rapid joint destruction and requires prompt diagnosis and treatment. The presence of fever, joint pain, redness, warmth, swelling, and elevated leukocytes in the synovial fluid supports this diagnosis.

## **Why the Correct Answer is Right**
The correct approach involves obtaining a synovial fluid culture to identify the causative organism, which is crucial for guiding antibiotic therapy. In septic arthritis, especially in a sexually active male, common pathogens include *Neisseria gonorrhoeae* and other bacteria. The synovial fluid analysis showing 200,000 leukocytes/uL and a low glucose level (< 30-50% of serum glucose) further supports the diagnosis. Immediate initiation of empiric antibiotics without waiting for culture results is often recommended, but obtaining cultures is essential. ## **Why Each Wrong Option is Incorrect** - **Option A:** This option is not provided, but typically, incorrect choices might involve delaying treatment, not addressing the infection directly, or choosing an inappropriate initial management step. - **Option B:** Similarly, without specifics, one might assume this could involve an incorrect diagnostic step or treatment approach not aligned with current guidelines for septic arthritis. - **Option C:** This might involve an action not directly related to addressing the likely diagnosis of septic arthritis or might not be the most immediate next step. ## **Clinical Pearl / High-Yield Fact** A key point to remember is that septic arthritis is a medical emergency. The synovial fluid analysis is critical, and empiric antibiotic therapy should be started promptly, often after blood cultures and synovial fluid cultures are obtained. In sexually active adults, coverage for *N. gonorrhoeae* should be included in the initial empiric regimen. ## **Correct Answer:** C. Obtain synovial fluid culture.