A 52-year-old man presents to the clinic with acute, severe pain and swelling in his right… — USMLE Step 3

A $52$ -year-old man presents to the clinic with acute, severe pain and swelling in his right knee that began $12$ hours ago. He reports the pain is so intense that he cannot tolerate the weight of his clothing over the joint. His medical history is significant for a deceased-donor renal transplant $4$ years ago for end-stage renal disease secondary to hypertensive nephrosclerosis. His current medications include cyclosporine, mycophenolate mofetil, prednisone ( $5\text{ mg}$ daily), and amlodipine. Temperature is $37.6^\circ\text{C}$ ( $99.7^\circ\text{F}$ ), blood pressure is $132/84\text{ mmHg}$ , and pulse is $88\text{/min}$ . Physical examination shows an erythematous, warm, and swollen right knee with exquisitely limited range of motion. Joint aspiration yields cloudy yellow fluid with a leukocyte count of $45,000\text{/mm}^3$ ( $85\%$ neutrophils). Polarized light microscopy reveals negatively birefringent, needle-shaped crystals. Gram stain of the synovial fluid shows no organisms. Serum creatinine is $1.6\text{ mg/dL}$ , which is at his baseline. Which of the following is the most appropriate initial pharmacologic intervention for this patient's acute joint condition?

Intra-articular triamcinolone injectionAnswer
B
Oral colchicine
C
Oral indomethacin
D
Oral probenecid
E
Intravenous ceftriaxone

Answer

Intra-articular triamcinolone injection is the most appropriate initial pharmacologic intervention for this patient.

The patient is experiencing an acute attack of monoarticular gout, confirmed by the pathognomonic finding of negatively birefringent, needle-shaped monosodium urate crystals. In a renal transplant recipient taking a calcineurin inhibitor (such as cyclosporine) who also has baseline renal impairment, standard systemic treatments for gout carry significant morbidity. Intra-articular glucocorticoid injections provide localized, rapid relief of monoarticular flares. This approach minimizes systemic absorption, completely avoiding dangerous drug-drug interactions and eliminating the risk of iatrogenic nephrotoxicity or allograft dysfunction.

Step-by-Step Solution

Analyze the synovial fluid results.

The presence of negatively birefringent, needle-shaped crystals with a leukocyte count of

45,000\text{/mm}^3

and negative Gram stain confirms an acute monoarticular gout flare.

Accurate diagnosis is required before selecting pharmacotherapy, differentiating severe inflammation from active infection.

Evaluate the patient's comorbidities and current medication list.

The patient is a renal transplant recipient taking cyclosporine with baseline renal impairment (creatinine

1.6\text{ mg/dL}

Systemic gout medications have severe toxicities and interactions in solid organ transplant patients.

Identify contraindications to standard systemic gout therapies.

NSAIDs are nephrotoxic (especially with calcineurin inhibitors), and colchicine has a potentially fatal CYP3A4/P-glycoprotein interaction with cyclosporine.

Recognizing these interactions prevents iatrogenic allograft failure or systemic toxicity.

Select the optimal localized therapy.

Intra-articular glucocorticoids (e.g., triamcinolone) bypass systemic absorption and avoid drug interactions.

It provides rapid, targeted relief for a single affected joint without compromising the renal allograft.

Key Concept

Management of acute gout in renal transplant patients requires avoiding systemic NSAIDs (due to nephrotoxicity) and colchicine (due to severe CYP3A4/P-glycoprotein interactions with calcineurin inhibitors) by utilizing targeted intra-articular glucocorticoids for monoarticular flares.

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