A 64-year-old Caucasian female presents to the clinic with vague symptoms of non- specific abdominal pain, myalgias, constipation, polyuria, and says she feels “fuzzy headed” much of the time. She had a fracture of her right metatarsal without trauma and currently is wearing a walking boot. She also had a bout of kidney stones a few weeks ago and she fortunately was able to pass the small stones without requiring lithotripsy or other interventions. She was told by the urologist to follow up with her primary care provider after the kidney stones has resolved.
Explain the processes involved in the formation of renal stones in patients with hyperparathyroidism.
Correct Answer:
Increased renal filtration load of calcium leads to hypercalciuria. Hypercalcemia also affects proximal renal tubular functions, causing metabolic acidosis and production of abnormally alkaline urine. PTH hypersecretion enhances real phosphate excretion and results in hypophosphatemia and hyperphosphatemia. The combination of hypercalciuria, alkaline urine, and hyperphosphaturia leads to the formation of renal stones