A 54 year old male presents to the clinic with severe pain in his left wrist and right great toe. 

A 54 year old male presents to the clinic with severe pain in his left wrist and right great toe.  The affected joints are swollen, erythematous and painful. The patient has limited range of motion of these joints. He denies injury to these areas. The patient is afebrile with a temperature of 98.8, all vital signs are within normal limits.

The patient has a history of hypertension and hyperlipidemia.  He has been steadily gaining weight over the past few years and is now about 50 pounds overweight.  He states that he drinks four to five beers each night and loves his steaks!

Serum Lab values:

WBC  5,400   Glucose  85 mg/dL Uric Acid  10.7 mg/dL BUN  8 mg/dL Creatinine  0.9 mg/dL Synovial fluid analysis showed many intracellular needle?shaped crystals; negative birefringence

1. Which of the lab values is the most likely cause of this patient’s swelling in his wrist and toe? Explain why this can cause pain.

2.   Describe the metabolic steps that produce the compound that is responsible for the pain in his joints.

3.   What is the most likely diagnosis?

4.    What is the most likely mechanism causing the abnormal lab value in this case?

5.   Describe the coupled enzymatic method for measurement of the elevated lab value. List any interfering substances.