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Evaluation and Management of Primary Hyperparathyroidism—Author’s Response¹

Columbia University College of Physicians & Surgeons New York, New York 10032

We have reported that, in our practice, most patients with asymptomatic primary hyperparathyroidism who do not meet NIH Consensus Conference guidelines for surgery are followed with no specific intervention (1, 2). In the preceding letter, Dr. S.J. Rosenbloom disagrees with this approach, proposing instead that all patients with primary hyperparathyroidism undergo parathyroidectomy. Surgical cure, he argues, should be undertaken to protect affected patients from the increased cardiovascular morbidity and mortality associated with hypercalcemia. Dr. Rosenbloom raises an important issue in the clinical characterization of primary hyperparathyroidism. Calcium clearly plays a critical role in vascular and cardiac function (3). In addition, parathyroid hormone itself has important inotropic and chronotropic effects on cardiac tissue (4). However, while we agree that primary hyperparathyroidism has the potential to involve the cardiovascular system, there have been no systematic investigations of this possibility in patients with the mild disease we are seeing today.

The studies cited by Dr. Rosenbloom describe patients with more severe or certainly more symptomatic primary hyperparathyroidism than we find in our population. The patients of Palmer et al. (5) presented with primary hyperparathyroidism from 1956 to 1979, many before the advent of the serum autoanalyzer, which allowed the diagnosis of asymptomatic disease. Although mortality increased in their population, it was unrelated to the preoperative levels of serum calcium. The cohort of Niederle et al. (6) was completely different from the patients we see in the United States today. Preoperatively, 85% of their patients (181/212) had symptoms of classical primary hyperparathyroidism, including nephrolithiasis, osteitis fibrosa cystica, and impaired renal function, while 11% were classified as having minimal symptoms. Only 4% of their patients were asymptomatic, as opposed to 80% of our cohort. The patients of Stefenelli et al. (7), who had an increased incidence of valvular and myocardial calcifications, had significantly higher serum calcium levels than we see (12 mg/dL vs. 10.7 mg/dL). Furthermore, parathyroid hormone levels were 10 times normal, alkaline phosphatase was twice normal, and 40% of patients had renal calcifications.

It is therefore impossible to extrapolate these observations to a cohort of patients with asymptomatic primary hyperparathyroidism. Nonetheless, these data and the letter of Dr. Rosenbloom do raise an important question: is the cardiovascular system a target organ in primary hyperparathyroidism? Systematic investigation is required to answer this question, and, subsequently, to determine the need for new therapeutic guidelines.

Footnotes

¹ Address correspondence to: Dr. Shonni J. Silverberg, Department of Medicine, Columbia University College of Physicians and Surgeons, 630 West 168th Street, PH-8W, New York, New York 10032.

Received December 4, 1996.

References

1. Silverberg SJ, Bilezikian JP. 1996 Evaluation and management of primary hyperparathyroidism. J Clin Endocrinol Metab. 81:236–240.[Abstract]
2. NIH Consensus Development Conference Statement on Primary Hyperparathyroidism. 1991 J Bone Miner Res. 6:s9–s13.
3. Tsien RW. 1990 Calcium channels in the cardiovascular system. In: Rosen MR, Janse MJ, Wit AL, eds. Cardiac electrophysiology. Mount Kisco: Futura; 75–90.
4. Fitzpatrick LA, Bilezikian JP. 1996 Actions of parathyroid hormone. In: Bilezikain JP, Raisz LR, Rodan GA, eds. Principles in bone biology. San Diego: Academic Press; 339–346.
5. Palmer M, Adami HO, Bergstrom R, Akerstrom G, Ljunghall S. 1987 Mortality after surgery for primary hyperparathyroidism: a follow-up of 441 patients operated on from 1956–1979. Surgery. 102:1–7.[Medline]
6. Niederle B, Roka R, Woloszczuk W, Klaushofer K, Kovarik J. 1987 Successful parathyroidectomy in primary hyperparathyroidism. Surgery. 102:903–909.[Medline]
7. Stefenelli R, Mayr H, Klein-Bergler J, Globits S, Woloszxzuk W, Niederle B. 1993 Primary hyperparathyroidism: Incidence of cardiac abnormalities and partial reversibility after parathyroidectomy. Am J Med. 95:197–202.[CrossRef][Medline]

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