A 47-year-old man comes to the office due to recurrent kidney stones. He passed his first stone 7 years ago and has subsequently passed 2 additional stones since then. Analysis of one of the stones revealed a stone content of 85% calcium oxalate and 15% calcium phosphate. His father and brother have both had kidney stones. His medical history is significant for gastroesophageal reflux disease, mild intermittent asthma, and psoriasis. He takes esomeprazole several times per week and uses an albuterol inhaler as needed for shortness of breath. He is allergic to sulfa medications. His blood pressure is 122/78 mm Hg and his pulse is 76/min. BMI is 27kg/m².
The patient's blood work from 6 months ago is shown below.
The patient's current laboratory studies reveal:
Which of the following is the most appropriate recommendation for this patient?

Question

A 47-year-old man comes to the office due to recurrent kidney stones. He passed his first stone 7 years ago and has subsequently passed 2 additional stones since then. Analysis of one of the stones revealed a stone content of 85% calcium oxalate and 15% calcium phosphate. His father and brother have both had kidney stones. His medical history is significant for gastroesophageal reflux disease, mild intermittent asthma, and psoriasis. He takes esomeprazole several times per week and uses an albuterol inhaler as needed for shortness of breath. He is allergic to sulfa medications. His blood pressure is 122/78 mm Hg and his pulse is 76/min. BMI is 27kg/m².
The patient's blood work from 6 months ago is shown below.

The patient's current laboratory studies reveal:

Which of the following is the most appropriate recommendation for this patient?

Quizplus · Accepted Answer

11ec193a_98f4_f320_853d_813665886a8a_MD0002_00 This patient with urolithiasis has a low urinary volume and idiopathic hypercalciuria, the main factors predisposing him to stone development. Dietary changes may reduce the incidence of stone formation (as shown in the table above). Calcium undergoes passive reabsorption in the proximal tubule along with sodium and water. A low sodium diet (<2300 mg/24 h) leads to increased proximal tubule calcium and sodium reabsorption, decreased calcium excretion, and a reduced overall incidence of calcium stones. High sodium intake increases urinary calcium excretion and should be avoided. Citrate can form a complex with calcium, thereby decreasing calcium stone formation. Dietary sources of citrate, such as 4 oz of lemon juice, can also increase urinary citrate excretion. However, lower than normal 24-hour urinary citrate excretion (as seen in this patient) is a risk factor for calcium stone formation, and citrate supplementation would be indicated to decrease stone formation. (Choice B) Long-term use of proton pump inhibitors is associated with increased risk of bone fractures, Clostridioides difficile infection, and hypomagnesemia. Esomeprazole has not been associated with an increased risk of kidney stones, and discontinuation of the drug would worsen this patient's gastroesophageal reflux disease. (Choice C) Calcium intake has a paradoxical response in calcium stone formation. Higher dietary calcium intake may result in gastrointestinal binding of calcium oxalate, thereby reducing urinary excretion of calcium and oxalate. However, lower calcium intake could potentially increase urinary calcium oxalate excretion, increasing the risk for future stones. (Choice D) Vitamin D supplementation has been linked to an increased risk of kidney stones and should be avoided in this patient. (Choice E) High intake of animal protein can potentially contribute to calcium urolithiasis by increasing urinary calcium excretion, increasing urinary uric acid excretion (which can facilitate calcium stone formation), and lowering urinary pH. Hyperuricosuria and low urinary pH increase the risk of uric acid kidney stones. Educational objective: Hypercalciuria is a common risk factor for the formation of calcium-containing kidney stones. Several dietary factors (as shown in below table) can have a favorable impact in reducing the incidence of calcium stones. 11ec193a_98f4_f321_853d_13bf4a41b789_MD0002_00 __________ References: Effects of a low-salt diet on idiopathic hypercalciuria in calcium-oxalate stone formers: a 3-mo randomized controlled trial. (http://www.ncbi.nlm.nih.gov/pubmed/20042524) Effect of dietary modification on urinary stone risk factors. (http://www.ncbi.nlm.nih.gov/pubmed/16221228)

A 47-Year-Old Man Comes to the Office Due to Recurrent