Primary hyperparathyroidism: four- to eight-year postoperative follow-up demonstrating persistent functional insignificance of microscopic parathyroid hyperplasia and decreased autonomy of parathyroid hormone release

Is focused parathyroidectomy appropriate for patients with primary hyperparathyroidism?

Purpose

The aim of this study was to determine whether focused or complete parathyroidectomy was more appropriate and to compare follow-up data in primary hyperparathyroidism (PHPT).

Methods

We retrospectively analyzed 225 operations for PHPT at Yonsei University Health System between 2000 and 2012. After excluding 93 patients, the remaining 132 were divided into 2 groups: those who underwent focused parathyroidectomy (FP) and those who underwent conventional parathyroidectomy (CP). We compared clinicopathological features; preoperative calcium, parathyroid hormone (PTH), phosphorus, vitamin D, 24-hour urine calcium, and alkaline phosphatase levels; postoperative calcium and PTH levels; pathologic diagnosis; multiplicity; and results of a localization study between the 2 groups.

Results

There was no significant difference in the rates of development of postoperative persistent hyperparathyroidism (1/122 FP patients and 1/10 CP patients) between the 2 groups due to a technical reason (FP 0.8% vs. CP 10.0%, P = 0.146). Multiglandular disease (MGD) was uncommon in all cases (6 of 132, 4.5%). All MGD cases were diagnosed using a preoperative localization study. Sestamibi scan and ultrasonography sensitivity were 94.2% and 90.2%, respectively.

Conclusion

We suggest that FP is appropriate in PHPT, except in cases of MGD if detected before the operation using preoperative imaging. Knowledge of hereditary PHPT and improved preoperative localization studies, such as high-resolution ultrasonography, contributed to the decision to perform FP rather than CP in all cases of unilateral results of the localizing study.

[Primary hyperparathyroidism. Postoperative normocalcemic hyperparathyrinemia after curative parathyroidectomy]

INTRODUCTION

Normocalcemic hyperparathyrinemia, i.e. elevated parathyroid hormone (PTH) levels after parathyroidectomy in patients with primary hyperparathyroidism (pHPT) may occur in the course of postoperative recovery without the development of persistence or relapse.

MATERIALS, METHODS AND RESULTS

Intraoperative and long-term (7 year) postoperative PTH and calcium levels after curative parathyroidectomy are demonstrated on the basis of a case report of a 62-year-old female patient with severe pHPT and pronounced osseous and renal manifestations. The intraoperative PTH gradient displayed a decrease from 1072 pg/ml to 13 pg/ml (normal range 11-67 pg/ml) followed by an increase of up to 287 pg/ml. The hyperparathyoid values decline to subnormal levels on administration of calcium and vitamin D and increase again after tapering these medications. The inverse calcium/PTH correlation in the course of the 7-year observation period suggests an intact feed-back mechanism. Preoperative PTH screening was performed in 316 consecutive normocalcemic thyroid patients to evaluate the rate of incidental hyperparathyroidism in patients with normal serum calcium levels. Of these patients 31 (9.8%) with normocalcemia (average 2.28 mmol/l, normal range 2.1-2.7 mmol/l) exhibited increased PTH levels averaging 84.2 pg/ml. A parathyroid adenoma was found intraoperatively as the cause for normocalcemic pHPT in only 1 of these 31 patients.

DISCUSSION AND CONCLUSIONS

A review of the literature revealed that late postoperative elevated parathyroid hormone levels after successful pHPT surgery occur in 21.5%. Multiple causes are discussed, e.g. reactive hyperparathyroidism in cases of relative hypocalcemia, hungry bone syndrome, vitamin D deficiency, renal dysfunction and ethnic or lifestyle differences. In mild cases of postoperative hyperparathyrinemia observation of the patient may be sufficient. In cases of reactive hyperparathyroidism due to hypocalcemia, administration of calcium is indicated, in symptomatic patients, additional administration of vitamin D or calcitriol is necessary. Vitamin D deficiency per se needs adequate substitution. In cases of ongoing hyperparathyrinemia an interdisciplinary diagnostic and therapeutic approach is required.

The clinical significance and anatomic distribution of parathyroid double adenomas

BACKGROUND

Parathyroid double adenomas are reported to occur in 3% to 12% of cases of primary hyperparathyroidism, but the very existence of double adenomas has been controversial. This study was undertaken to evaluate the clinical significance and anatomic distribution of parathyroid double adenomas.

STUDY DESIGN

The medical records of 384 consecutive patients who underwent operation for primary hyperparathyroidism were reviewed.

RESULTS

A total of 27 patients (7%) were found to have double parathyroid adenomas. Intraoperative parathyroid hormone (PTH) levels were measured in each case. Two enlarged hypercellular parathyroid glands were identified in 6 possible configurations: 10 both superior, 3 both inferior, 5 both right, 3 both left, 5 right superior and left inferior, and 1 left superior and right inferior. There was preferential distribution to the bilateral superior position (p = 0.008). In all patients intraoperative PTH levels dropped by at least 50% from baseline and into the normal range after removal of both abnormal parathyroid glands. All patients remain normocalcemic 1 to 26 months postoperatively. Two patients have persistently elevated PTH values with normal serum calcium levels.

CONCLUSIONS

The drop in intraoperative PTH levels and maintenance of normocalcemia postoperatively confirm previous reports that double adenomas do exist and are not simply missed cases of four-gland hyperplasia. Their incidence is more than would be expected by chance alone. The preferential occurrence of bilateral superior double adenomas suggests the possibility that these may represent hyperplasia of parathyroids arising from the fourth branchial pouch rather than isolated neoplastic events.

Minimally invasive parathyroid surgery

More surgeons are performing unilateral exploration for primary hyperparathyroidism (HPT) than ever before. This article reviews the factors that have led to the trend toward less invasive surgery. Discussion includes the history of unilateral exploration for HPT, the advent of magnetic resonance sestamibi imaging, and the development of intraoperative assays for parathyroid hormone. Results of minimally invasive techniques, including radio-guided parathyroidectomy, endoscopic parathyroidectomy, and outpatient parathyroidectomy, also are presented.

Normocalcemic hyperparathyroidism in Vietnamese immigrants living in southern California

OBJECTIVE

To characterize the normocalcemic hyperparathyroidism in Vietnamese immigrants living in southern California.

METHODS

Of 14 Vietnamese patients with primary hyperparathyroidism who were observed between 1991 and 1996, 50% (7 patients; 2 men and 5 women) had normal and/or fluctuating levels of serum total calcium. When the serum calcium was corrected for the albumin, the "corrected" calcium was lower than the measured serum total calcium. Their mean age was 56.4 +/- 11.4 years. All patients had normal serum levels of albumin and serum phosphate.

RESULTS

Women were affected more often than men by a ratio of 5:2. The serum-ionized calcium as well as intact PTH were increased in all patients. Five patients underwent surgery with confirmation of parathyroid adenomas. Two patients refused surgery. They did not have osteitis fibrosa cystica by radiological examination. One patient had low plasma levels of 25-hydroxyvitamin D. Five of 7 normocalcemic patients (70%) were born in the month of December compared with 2 of seven hypercalcemic patients (30%).

CONCLUSION

The blood ionized calcium and intact parathyroid hormone are necessary for confirmation of normocalcemic hyperparathyroidism. Most of our normocalcemic hyperparathyroid patients (70%) were born in the month of December. We postulate that a combination of exposure to solar ultraviolet light during the formation of the fetal parathyroid glands and stimulation from low vitamin D levels in the wintertime may be related to the development of hyperparathyroidism. However, it is difficult to prove a definite correlation between normocalcemic hyperparathyroidism and their month of birth (December), especially when these observations were seen in a small group of patients.

Secondary hyperparathyroidism is an expected consequence of parathyroidectomy for primary hyperparathyroidism: a prospective study

BACKGROUND

Parathyroidectomy for primary hyperparathyroidism (PHPT) can cause secondary hyperparathyroidism, with increased serum parathyroid hormone (PTH) and normal or low serum calcium concentrations.

METHODS

A prospective study investigated 78 consecutive patients who underwent exploration for PHPT. Serum intact PTH and total calcium concentrations were measured the evening after operation and ionized Ca++ the following morning. These levels were reassayed 1 week later.

RESULTS

Before operation, the mean PTH level was 138 +/- 15 pg/mL, total calcium concentration was 11.6 +/- 0.1 mg/dL, and ionized Ca++ concentration was 1.44 +/- 0.02 mmol/L. On the night of the operation, the PTH level was 11 +/- 2 pg/mL, and the total calcium concentration was 8.9 +/- 0.1 mg/dL. Fifty-five patients had hypoparathyroidism, with a PTH level less than 10 pg/mL. The day after the operation, the ionized Ca++ level was 1.14 +/- 0.01 mmol/L. One week later, PTH, ionized Ca++, and total serum calcium concentrations returned to normal levels. In 9 patients (12%), PTH levels were increased (98 +/- 16 pg/mL), although ionized Ca++ concentrations were normal (1.18 +/- 0.02 mmol/L), demonstrating secondary hyperparathyroidism. Risk factors for postoperative secondary hyperparathyroidism included older age, symptomatic hyperparathyroidism, higher preoperative PTH and alakaline phosphatase levels, and lower serum phosphorous levels. In 70% of these patients, PTH levels returned to normal in 3 to 12 months.

CONCLUSIONS

Secondary hyperparathyroidism occurs in 12% of patients after surgical treatment of PHPT. It is transient, possibly compensating for relative hypocalcemia.

SOME CHARACTERISTICS OF PRIMARY HYPERPARATHYROIDISM IN VIETNAMESE IMMIGRANTS LIVING IN SOUTHERN CALIFORNIA

OBJECTIVE

To characterize primary hyperparathyroidism (PHP) in Vietnamese immigrants living in southern California and to summarize the results of treatment.

METHODS

We describe 11 patients (8 women and 3 men) with a mean age of 57.91 years who underwent follow-up from 1991 to 1995 after PHP was diagnosed. The patients had no specific complaints. Four patients had a history of kidney stones, and five had chronic hypertension. Only five patients had high levels of total serum calcium; the other six patients had normal or fluctuating levels of total serum calcium. All patients, however, had high levels of intact parathyroid hormone (PTH) and ionized calcium. Preoperatively, parathyroid imaging with technetium-99m sestamibi demonstrated persistently increased parathyroid gland uptake.

RESULTS

In all nine patients who underwent surgical treatment, an adenoma was found in the parathyroid glands; two patients refused operative intervention. The mean serum phosphate was in the low-normal range and increased postoperatively (2.70 versus 3.52 mg/dL; P<0.001). The mean serum chloride level also decreased postoperatively (104.62 versus 100.78 mEq/L; P<0.001). The ratio of chloride/phosphate decreased significantly after adenoma removal (39.44 versus 29.21; P<0.001). Six patients received calcium gluconate either alone or in combination with vitamin D supplements for hypocalcemia postoperatively. The other three patients, however--who did not receive calcium supplements postoperatively--had persistently high levels of intact PTH but normal serum Ca++ levels and subsequently were treated effectively with calcium gluconate and vitamin D.

CONCLUSION

The presence of hypercalcemia, especially Ca++, and an increased level of intact PTH establishes the diagnosis of PHP. After parathyroidectomy, the persistence of high levels of intact PTH in association with normal serum Ca++ suggested the presence of secondary hyperparathyroidism, which was treated effectively with calcium gluconate and vitamin D. These patients had the same clinical picture as other ethnic groups with PHP, but they needed either calcium alone or calcium and vitamin D supplements after parathyroidectomy because of their bone loss from prolonged PHP.

Clinical and surgical aspects of double adenoma in patients with primary hyperparathyroidism

The incidence of double parathyroid adenoma in 277 prospectively documented patients suffering from primary hyperparathyroidism was 5.4 per cent (15 patients). Patients with double adenoma were all symptomatic and had a significantly higher parathyroid hormone (PTH) level and tumour weight than those with a solitary adenoma or four-gland hyperplasia. In 11 patients the adenomas were located bilaterally. Bilateral neck exploration must be performed routinely to deal successfully with this condition at initial operation. In six patients one enlarged gland was found in the thymus or posterior mediastinum. These locations should be explored, especially in patients with high PTH levels, in those in whom all four parathyroid glands cannot be detected or if only one small adenoma is found. In all such patients, selective resection of the enlarged parathyroid glands resulted in normocalcaemia (median follow-up 3.5 years). Selective resection of the pathological glands is the treatment of choice.

Double parathyroid adenomas. Clinical and biochemical characteristics before and after parathyroidectomy

OBJECTIVE

There is considerable debate about whether double parathyroid adenomas are a discrete entity or represent hyperplasia with parathyroid glands of varying sizes. This distinction is important because it impacts on the extent of parathyroid resection and the success of the parathyroid operation.

SUMMARY BACKGROUND DATA

Double parathyroid adenomas have been reported to occur in 1.7% to 9% of patients with primary hyperparathyroidism (HPT). It is important for surgeons to differentiate between double adenoma and hyperplasia with glands of varying sizes using gross examination during the initial procedure because microscopic findings of a small biopsy specimen at frozen-section examination may not be diagnostic.

METHODS

From 1982 to 1992, 416 unselected patients (309 women and 107 men) with primary HPT without familial HPT or multiple endocrine neoplasia (MEN) were treated by one surgeon at the University of California at San Francisco. Double adenoma occurred in 49 patients, solitary adenoma in 309 patients, and hyperplasia in 58 patients. The authors analyzed the clinical manifestations, the preoperative and postoperative serum levels of calcium, phosphate, and parathyroid hormone (PTH), and the success rate and outcome after parathyroidectomy and compared their results in 49 patients with double adenomas to the results for patients with solitary adenomas or hyperplasia.

RESULTS

Ten of the patients with double adenomas (20.4%) were referred for persistent HPT after removal of one abnormal parathyroid gland. The ages of the patients with double adenoma, single adenoma, and hyperplasia were 61 +/- 14, 56 +/- 15, and 58 +/- 7 years, respectively. Fatigue, muscle weakness, and bone pain were common in patients with double adenomas, whereas nephrolithiasis occurred more frequently in patients with solitary adenoma (p = 0.0001). Serum calcium and PTH levels (per cent of upper limit of normal) fell from 11.5 +/- 1.2 mg/dL and 487% to 9.5 +/- 0.8 mg/dL and 61% for patients with double adenomas; from 11.9 +/- 0.9 mg/dL and 378% to 9.3 +/- 1.4 mg/dL and 101% for patients with single adenoma; and from 10.9 +/- 0.5 mg/dL and 418% to 9.1 +/- 0.7 mg/dL and 94% for patients with hyperplasia, respectively. There was no recurrence in the patients with double adenomas with a mean follow-up time of 5.8 years.

CONCLUSIONS

Double adenomas are a discrete entity and occur more often in older patients. Patients with double adenomas can be successfully treated by removal of the two abnormal glands.

Initial failure of surgical exploration in patients with primary hyperparathyroidism

To determine the causes of failures of cervical exploration for primary hyperparathyroidism, we reviewed 892 patients operated on by one surgeon from 1953 to 1990. Twenty-seven patients (3%) remained hypercalcemic or developed hypercalcemia within 6 months of surgery. Of these, five patients had one adenoma removed initially; at reoperation, three patients had a second adenoma that was successfully removed, whereas the other two patients had hyperplasia and required subtotal parathyroidectomies. No enlarged parathyroid glands were identified in 22 patients. Eventually, six patients became normocalcemic spontaneously, seven patients underwent re-exploration with a successful outcome in all but one case, two patients had ectopic hyperparathyroidism associated with carcinoma elsewhere, and seven patients refused reoperation and remain hypercalcemic. The failure rate of surgical exploration for primary hyperparathyroidism can be reduced by systematically exploring all four parathyroid glands. All abnormal parathyroids should be removed with histologic verification. When no abnormal glands are found, localization studies should be performed before re-exploration.

The parathyroid gland in health and disease

The authors studied the parathyroid glands from 100 previously healthy subjects who died suddenly and were admitted to the Dade County Medical Examiner's (ME) morgue and from 66 inpatients who died at Jackson Memorial Hospital (JMH). Parathyroid glands in patients with diseases (JMH series) were heavier than those in healthy persons (ME series), and both groups of glands were significantly heavier than those previously reported. Mean glandular weight in white subjects was 42.6 +/- 20.3 mg, with a range of 22-103 mg. The 95% upper limit of gland weight for healthy white subjects was 73.1 mg and for black subjects, 91.6 mg. The size and weight exhibited a skewed distribution. Gland weight varied with age, increasing to a maximum in the 41-60 year old age group in all subsets except white women, in whom it continued to increase till after age 70. There was slight correlation (r2 = 0.15) of gland weight with body weight within series and race groups; parenchymal content of the glands was not constant but correlated positively with glandular weight. Glands from both series had a comparable fat content. Fat was unevenly distributed throughout the gland, and its amount was highly variable, ranging between 0 and 90%, with a mean of 26% for white subjects and 24% for black subjects in both series. Therefore, percentage fat may not be used as an index of hyperplasia. Healthy back subjects had heavier glands than healthy white subjects, unaccounted for by differences in body weights; this difference was not statistically significant in subjects with disease. Within the black race, glands were not significantly heavier in disease than in health, and in the few cases with serum calcium determinations, the gland weight did not vary inversely with serum calcium levels as in white subjects, suggesting a basic difference in parathyroid calcium metabolism between the two races.

Hyperparathyroidism associated with the enlargement of two or three parathyroid glands

Eighty-five (23%) of 375 patients undergoing surgery for primary hyperparathyroidism were found to have enlargement (greater than 50 mg) of two or three parathyroid glands. Of 76 patients followed from 12 to 140 months after surgery, eight (10.5%) developed hypercalcemia at 1, 4, 45, 64, 74, 79, 84, and 133 months. In a comparison of pertinent preoperative biochemical and pathologic data between 55 patients with two- or three-gland hyperparathyroidism and 55 age- and sex-matched patients with single-gland hyperparathyroidism, only the preoperative serum phosphate differed significantly, being lower in the patients with single-gland disease (2.4 +/- 0.1 vs. 2.6 +/- 0.1; p less than 0.04). In the eight patients with two- or three-gland hyperparathyroidism who developed postoperative hypercalcemia, the preoperative concentrations of serum calcium were lower (10.8 +/- 0.2 vs. 11.5 +/- 0.2; p less than 0.019), the preoperative concentrations of serum phosphate were higher (3.1 +/- 0.2 vs. 2.5 +/- 0.1; p less than 0.020), and the weights of the excised parathyroid tissues were less (356 +/- 72 mg vs. 1354 +/- 215 mg; p less than 0.02) than those of patients with two- or three-gland disease who did not develop postoperative hypercalcemia, indicating a milder form of hyperparathyroidism. In the 68 patients without recurrent hypercalcemia, there was no tendency for the serum calcium concentration to increase with time. Patients with primary hyperparathyroidism associated with two or three enlarged parathyroid glands have an appreciable incidence of persistent or recurrent hypercalcemia, which may increase even further with longer observation.

Hyperparathyroidism: problems in surgical management

A retrospective study of 210 patients who had 225 operations for hyperparathyroidism over a 20 year period has been reported. These patients were operated on by 20 staff surgeons, 12 of whom performed such an operation less than five times for this disease during the study period. There was a significant operative and postoperative morbidity of about 8 percent. There was one postoperative death, and two patients died later of related problems. The recurrence rate was 1 percent. The total rate of untoward results was about 18 percent. The success rate of primary operations was 95 percent (71 percent for reoperations). These findings were similar to those in many published reports, but were less than satisfactory. It is possible that results could be improved by putting such patients in the care of experienced surgeons. Careful identification of all of the parathyroid glands is essential to obtain satisfactory results. There was an unusually large incidence of this disease in patients with thyroid disease, immobilization, and thiazide intake. There was a correlation between the preoperative serum calcium levels and the size of the parathyroid tumors that were removed. An interesting "rebound" postoperative hypercalcemia has been described.