Question

A 54 year old man presents with acute knee pain which began last night while he was sleeping. He is now in 9/10 pain and says that he is hardly able to walk secondary to his inability to flex his left knee. Past medical history includes hypertension, nephrolithiasis, and two similar episodes of pain that have occurred over the past 16 months, one in his toe and another in his left knee. On physical exam, the patient is visibly uncomfortable and is holding his leg perfectly still. There is marked erythema and soft tissue swelling surrounding the knee. Passive range of motion is severely diminished secondary to the patient's pain. Analysis of joint aspirate shows a WBC of 60,000 and abundant needle shaped crystals that show negative birefringence under a polarizing filter. Treatment is initiated with colchicine, prednisone, and indomethacin. What is the next most appropriate step in the management of this patient?

A. 24 hour urine collection for uric acid
B. Measurement of serum uric acid
C. Plain film x-rays of knee
D. Begin therapy with allopurinol
E. Begin therapy with probenecid

Answer 1

The next most appropriate step in the management of this patient is Measurement of serum uric acid. Elevated serum uric acid levels are crucial in confirming the diagnosis of gout and guiding treatment decisions. Thus the correct option is B. Measurement of serum uric acid.

Step-by-step explanation:

The patient's presentation, with acute knee pain, erythema, soft tissue swelling, and needle-shaped crystals with negative birefringence in joint aspirate, is indicative of gout. Gout results from the deposition of monosodium urate crystals in joints, leading to inflammation. While the patient has a history of nephrolithiasis, indicative of uric acid involvement, measuring serum uric acid levels is crucial. This step aids in confirming the diagnosis and guides treatment decisions.

Elevated serum uric acid levels are a hallmark of gout, and addressing the underlying hyperuricemia is crucial for long-term management. In this acute setting, identifying and treating the precipitating cause, such as dietary factors or dehydration, is essential.

Initiating allopurinol or probenecid at this point could potentially exacerbate the acute episode. Therefore, measuring serum uric acid levels is the logical next step, allowing for a comprehensive understanding of the patient's baseline and aiding in tailored management.

In summary, the next step is to measure serum uric acid levels (Option B), as it provides essential information for confirming the diagnosis and planning appropriate long-term management.

Thus the correct option is B. Measurement of serum uric acid.