We present four treatment categories for patients with primary hyperparathyroidism and describe the results of studies of patients in each category. These categories are primary surgical, secondary surgical, “biochemical” hyperparathyroidism and medical management with oral administration of neutral phosphate. The importance of the parathyroid surgeon as a diagnostician during parathyroid exploration is stressed from the point of view of the detection and aggressive surgical treatment of parathyroid chief cell hyperplasia. Short-term (1 to 2 weeks) and long-term (5 to 29 months) studies of the state of parathyroid function in relation to calcium homeostasis after successful resection of hyperfunctioning parathyroid tissue are described.

Although incomplete, our 5 year prospective study of “biochemical” hyperparathyroidism shows that in approximately 20 per cent of these patients the disease progresses to where our criteria for surgical intervention are met and that no one criterion or combination of criteria has been identified as being of predictive value in determining which patients will ultimately require surgical intervention. In patients with persistent or recurrent hyperparathyroidism, chronic oral treatment with neutral phosphate was successful in decreasing serum calcium from more than 12.0 mg/dl to less than 11.0 mg/dl in four of seven patients, but significant increases in serum creatinine occurred in three of these seven patients. Significant decreases in serum calcium did not occur in patients with serum calcium values less than 11.0 mg/dl, and there were no changes in serum creatinine in this group. Nephrolithiasis was controlled in seven of eight patients, but the specific effectiveness of neutral phosphate treatment in all these patients could not be assessed because only two had metabolically active disease at the start of treatment.