A 31-year-old man comes to the office due to joint pains. About a week ago, the patient woke with some stiffness in his back and right heel; he subsequently developed right knee pain leading to difficulty ambulating. Two months ago, the patient was treated for urethral discharge at an outside clinic, and his genitourinary symptoms completely resolved. He has no history of trauma or illicit drug use. Temperature is 37.2 C (99 F). The right knee is swollen, tender, and warm to the touch; there is tenderness to palpation over the Achilles tendon and the sacroiliac joints. Oral examination shows mouth ulcers. Synovial fluid analysis from the right knee reveals a white blood cell count of 10,000/mm³ with many polymorphonuclear leukocytes; Gram stain reveals no organisms. Which of the following is the most appropriate initial pharmacotherapy for this patient?

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11ec25c8_d51a_7301_bc81_6d037abb1a02_MD0003_00 This patient has inflammatory knee arthritis (eg, warm, swollen knee; elevated synovial fluid leukocyte count), Achilles tendinitis, sacroiliitis, and oral ulcers that developed weeks after an infection. This presentation is consistent with reactive arthritis, a postinfectious seronegative spondyloarthropathy typically manifesting weeks after an infection, usually involving the gastrointestinal (Salmonella, Shigella, Campylobacter) or genitourinary (eg, Chlamydia urethritis) tract. Classic reactive arthritis consists of asymmetric oligoarthritis (often involving the knee and sacroiliac joints), conjunctivitis, and aseptic urethritis. However, this triad is rare, and the presentation is variable. Mucocutaneous lesions and enthesitis (eg, Achilles tendon insertion site, tibial tuberosity) are common findings. There should be a high index of suspicion with any asymmetric oligoarthritis associated with mouth ulcers, urethritis, or conjunctivitis. Synovial fluid analysis reveals an elevated white blood cell count, but the fluid is usually sterile (eg, no organisms on Gram stain or culture). The pathophysiology is multifactorial but likely reflects activated lymphoid cells (from infection) migrating to joints or extraarticular sites and causing inflammation; nonsteroidal anti-inflammatory drugs are first-line therapy. Antibiotics do not treat the arthritis but may be indicated depending on the underlying infection; they are not necessary in this patient whose urethritis was treated and genitourinary symptoms resolved, and early antibiotic therapy does not prevent arthritis development (Choice B). Although gonococcal septic arthritis (negative synovial fluid cultures in ~50% of cases) can be difficult to distinguish from reactive arthritis, this patient is afebrile, his synovial fluid count is less concerning for septic arthritis, and his manifestations (eg, mouth ulcers, enthesitis, sacroiliitis) suggest reactive arthritis. synovial fluid count (Choices A and D) Colchicine (tubulin polymerization inhibitor) is used in acute gout. Allopurinol (xanthine oxidase inhibitor) is used as uric acid lowering therapy in gout. Gout does not typically cause mouth ulcers, and reactive arthritis is not due to increased uric acid levels. (Choice C) Although some patients with osteoarthritis take chondroitin sulfate, a component of the ground substance that composes cartilage, to improve their symptoms, it has not been definitively shown to improve symptoms and outcomes in osteoarthritis and would not be used to treat inflammatory arthritis. Educational objective: Reactive arthritis is a seronegative spondyloarthropathy resulting from an infection, typically enteric or genitourinary in origin. Findings may include urethritis, conjunctivitis, mucocutaneous lesions, enthesitis, and oligoarthritis. Nonsteroidal anti-inflammatory drugs are first-line therapy.

A 31-Year-Old Man Comes to the Office Due to Joint