Examkin

Question

Difficulty: HardPharmacologic Interventions

A 55-year-old man is evaluated in the urgent care clinic for severe pain, swelling, and redness in his right knee that began abruptly overnight. The pain is exacerbated by minimal movement, and he has been unable to bear weight on the right leg today. He has a history of end-stage renal disease secondary to IgA nephropathy, for which he received a deceased-donor renal transplant 3 years ago. His maintenance immunosuppressive regimen consists of cyclosporine, mycophenolate mofetil, and prednisone 5 mg daily. He also takes amlodipine for hypertension. His temperature is 37.6°C (99.7°F), blood pressure is 138/86 mmHg, and pulse is 92/min. Physical examination reveals marked erythema, warmth, and a moderate effusion of the right knee. Arthrocentesis yields 15 mL of cloudy yellow synovial fluid. Synovial fluid analysis shows a leukocyte count of 28,000/mm³ with 85% neutrophils. Polarized light microscopy demonstrates negatively birefringent, needle-shaped crystals. Gram stain of the fluid is negative. Serum creatinine is 1.7 mg/dL (baseline 1.6 mg/dL). Which of the following is the most appropriate next step in the pharmacologic management of this patient?

  1. Intra-articular triamcinolone acetonideAnswer
  2. B
    Oral colchicine
  3. C
    Oral indomethacin
  4. D
    Oral allopurinol
  5. E
    Intravenous vancomycin and ceftriaxone

Answer

Intra-articular triamcinolone acetonide
The correct answer is intra-articular triamcinolone acetonide. This patient is presenting with an acute gout flare, confirmed by the pathognomonic finding of negatively birefringent, needle-shaped monosodium urate crystals in an inflammatory synovial fluid. The management of acute gout typically involves NSAIDs, colchicine, or glucocorticoids. However, this patient's status as a renal transplant recipient on a specific immunosuppressive regimen severely restricts his options. Intra-articular glucocorticoids are highly effective for monoarticular gout and represent the safest choice for this patient, as they act locally and avoid the severe systemic drug interactions and nephrotoxic risks associated with the alternatives.

Step-by-Step Solution

1
Analyze the clinical presentation and synovial fluid results.
The patient has an acute monoarthritis. Synovial fluid shows 28,000 WBCs/mm³, negatively birefringent needle-shaped crystals, and a negative Gram stain, confirming an acute gout flare without superimposed septic arthritis.
Establishing the correct diagnosis is required before selecting targeted pharmacotherapy.
2
Evaluate the patient's medical history and current medication list for potential contraindications or interactions with standard gout therapies.
The patient is a renal transplant recipient taking cyclosporine (a calcineurin inhibitor and potent P-glycoprotein inhibitor). He also has a baseline elevated creatinine (1.6 mg/dL).
Standard first-line treatments for acute gout include NSAIDs, colchicine, and systemic or intra-articular glucocorticoids. Comorbidities dictate which options are safe.
3
Select the safest and most effective pharmacologic intervention based on the patient's specific constraints.
NSAIDs are contraindicated due to the risk of calcineurin inhibitor-induced nephrotoxicity. Colchicine is contraindicated due to a severe drug-drug interaction with cyclosporine. Intra-articular glucocorticoids are safe and effective.
Intra-articular injection treats the local inflammation effectively while avoiding the systemic toxicities and drug interactions associated with oral alternatives.

Key Concept

Management of acute gout flares in patients with significant comorbidities requires careful avoidance of NSAIDs in renal impairment/calcineurin inhibitor use, and avoidance of colchicine in the presence of strong P-glycoprotein or CYP3A4 inhibitors (e.g., cyclosporine). Intra-articular glucocorticoids are the safest option for monoarticular flares in these populations.
Rate this question

Topics

Pharmacologic Interventions

More questions from this topic