A 28-year-old man presented with right knee pain for two weeks. He had no past medical history or trauma. He denied the use of any illicit drugs or previous experience of knee pain. However, he had tried over-the-counter medications without any relief, and his condition deteriorated. Upon examination, the patient’s knee was warm, swollen, and erythematous. The patient was afebrile. He was unable to bear weight or move his right leg.
Laboratory counts revealed WBC counts to be 12,100 per microliter (mcL). Soft, mild tissue swelling and effusion were observed. Fluid analysis revealed 28,875 WBC/mcL. Bacterial culturing and Gram Staining revealed Gram-positive Staphylococcus lugdunensis . MRI images are provided for your reference. What can be the most probable diagnosis for this man? *This Case Challenge is from the Editorial Team of Docplexus and is meant for educational purposes only.…
