Pitfalls in parathyroid evaluation in patients with calcium urolithiasis.

Primary hyperparathyroidism is a major cause of calcium urolithiasis and is easily recognised when it is classically manifested. However, subtle presentations of primary hyperparathyroidism may cause confusion with other causes of calcium stone disease or cause diagnostic difficulty. Several pitfalls of parathyroid evaluation and treatment are illustrated by four cases of calcium urolithiasis. Cases 1 and 2 represent ineffective or useless parathyroid surgery rendered for renal hypercalciuria and absorptive hypercalciuria, respectively. Cases 3 and 4 had mild or intermittent hypercalcaemia. The correct diagnosis of primary hyperparathyroidism was made in Case 3 by parathyroid venous sampling and bone densitometry. In Case 4, the thiazide provocative test was used to establish the diagnosis of primary hyperparathyroidism.