Unexpected parathyroid disease discovered at thyroidectomy in irradiated patients

Eight of 23 patients undergoing total thyroidectomy for radiation-associated nodular thyroid disease were found to have unsuspected parathyroid hyperplasia or adenoma at operation. The total serum calcium level was normal preoperatively in each patient. Serum ionized calcium and parathyroid hormone levels were measured in five patients preoperatively and were normal in each case. These pathologic findings in normocalcemic patients may represent a preclinical form of hyperparathyroidism, which would be further evidence linking radiation to the pathogenesis of hyperparathyroidism. The parathyroid glands should be evaluated both preoperatively and at operation in all patients who have a history of radiation and require thyroidectomy.     

Parathyroid Adenomas versus Four-gland Hyperplasia as the Cause of Primary Hyperparathyroidism in Patients with Prolonged Lithium Therapy

Chronic lithium therapy in patients with affective psychiatric disorders has been implicated as the cause of hypercalcemia and primary hyperparathyroidism. Our objective was to evaluate whether primary hyperparathyroidism was caused by an adenoma or four-gland hyperplasia. The medical records of 15 patients with affective psychiatric disorders who were treated with chronic lithium therapy from 1982 to 1997, all of whom were operated on for primary hyperparathyroidism, were reviewed. Data on age, symptoms, duration of lithium therapy, pre- and postoperative calcium levels, and parathyroid hormone levels were collected. Parathyroid histology for each patient was independently and blindly reviewed. The mean age was 58 +/- 10 years, the mean duration of lithium therapy 10.7 +/- 6 years, and the mean preoperative calcium level 11.7 +/- 0.5 mg/dl. All patients underwent bilateral neck exploration with selective resection of enlarged glands. Of the 15 patients, 14 (92%) had adenomas (11 single, 3 double), and 1 (8%) had four-gland hyperplasia. All patients were rendered eucalcemic, with a postoperative calcium level of 9.2 +/- 0.5 mg/dl ( p < 0.005). All patients resumed their lithium therapy, with 1 of 15 patients developing recurrent hyperparathyroidism 2 years following the first operation; this patient required reexploration, at which time an adenoma was resected. In our experience hyperparathyroidism in patients who have undergone prolonged therapy with lithium is associated with a high incidence of parathyroid adenomas versus four-gland hyperplasia. This suggests that lithium selectively stimulates growth of parathyroid adenomas in susceptible patients, who are best treated with adenoma excision rather than subtotal parathyroidectomy.     

Operative treatment of tertiary hyperparathyroidism: a single-center experience.

OBJECTIVE: To review the experience with the operative treatment of tertiary hyperparathyroidism (TH) from a single renal transplant center. SUMMARY BACKGROUND DATA: Most patients with chronic renal failure show evidence of secondary hyperparathyroidism by the time maintenance hemodialysis begins. Persistent secondary hyperparathyroidism (i.e., TH) requiring surgical intervention is uncommon in the authors' experience. METHODS: Charts of patients who underwent parathyroidectomy for TH were reviewed retrospectively. Information obtained included demographics, laboratory data, symptoms, operative procedure (including morbidity and mortality rates), and pathology. Comparisons of demographic data and allograft survival were made between the transplant population as a whole and a matched cohort group of patients. RESULTS: Thirty-eight patients from 4344 renal transplant procedures during a 29-year period required parathyroidectomy for TH. All patients had hypercalcemia; 20 were asymptomatic and 18 had varying symptoms. Mean time from renal transplantation to parathyroidectomy was 997 +/- 184 days, with a mean preoperative calcium level of 12.2 +/- 0.14 mg/dl. Total parathyroidectomy with parathyroid autograft was performed in 26 of 34 primary procedures. There were no deaths. The operative morbidity rate was 6% (wound separation and vocal cord hemiparesis, one each). Pathology was reported in all patients and recently reviewed in 28 patients. Twenty-four had diffuse hyperplasia and nine had nodular hyperplasia; one had an adenoma. Parathyroid glands diagnosed as nodular hyperplasia were significantly larger by total mass than those with diffuse hyperplasia. Comparison of allograft survival between the study group and a matched cohort group of patients revealed no difference in long-term graft survival. CONCLUSIONS: Operative intervention is recommended in patients with an asymptomatic increase in serum calcium to >12.0 mg/dl persisting for >1 year after the transplant, acute hypercalcemia (calcium >12.5 mg/dl) in the immediate posttransplant period, and symptomatic hypercalcemia.     

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

Thirty-nine patients with primary hyperparathyroidism were studied four to eight years after their initial operation. In six patients, both the pathologist and surgeon agreed on the diagnosis of solitary adenoma; in 16 patients, the surgeon diagnosed solitary adenoma and the pathologist parathyroid hyperplasia (microscopic hyperplasia). In 16 patients, primary chief cell hyperplasia was agreed upon by the pathologist and surgeon. In the 16 patients with microscopic hyperplasia, there have been no long-term recurrences of hypercalcemia, but, in two patients, plasma parathyroid hormone levels are high. Parathyroid hormone--total calcium regression curves demonstrate significant preoperative correlation in solitary adenoma, p less than 0.01, and primary chief cell hyperplasia, p less than 0.05. After operation, significant correlations were not found between parathyroid hormone and total calcium. T-testing slope differences of pre- and postoperative parathyroid hormone--total calcium regression curves demonstrates a significant (p less than 0.01) shift to the right of the microscopic hyperplasia patients after operation, moving them to a broader range of total calcium per picogram parathyroid hormone. We conclude that 1) in primary hyperparathyroidism, positive regulation of total calcium by autonomously released parathyroid hormone exists in patients with solitary adenoma and chief cell hyperplasia; 2) autonomously functioning parathyroid tissue has been removed by operation for solitary adenoma with coexistent microscopic parathyroid hyperplasia. In this four- to eight-year follow-up period, it is clear that microscopic parathyroid hyperplasia is not associated with recurrent hypercalcemia. Two functionally distinct forms of parathyroid suppression are suggested; positively regulated microscopic hyperplasia and negatively regulated pathologically suppressed glands.     

Parathyroidectomy in familial hypercalcemia with clinical characteristics of primary hyperparathyroidism and familial hypocalciuric hypercalcemia

BACKGROUND: Familial primary hyperparathyroidism is associated with tumor-susceptibility syndromes, which are unrelated to mutations in the calcium receptor gene. This study describes parathyroidectomy in a kindred with hypercalcemia due to a heterozygous point mutation in the calcium receptor gene. METHODS: Seventeen family members were studied, and postoperative follow-up averaged 5.1 years. RESULTS: Radical parathyroid resection with total parathyroid remnants of 10 to 20 mg or total parathyroidectomy with autotransplantation normalized the serum calcium and parathyroid hormone values in 12 family members. Persistent hypercalcemia was noted in 3 of 5 patients subjected to less radical procedures. Diffuse to nodular hyperplasia and microscopic findings, interpreted incorrectly as a single adenoma, were found. Weight of the parathyroid tissue increased with the age of the patients (P <.05), and almost one third of them (29%) had 1 to 3 atypically located glands. There were no patients with recurrent hypercalcemia during follow-up. CONCLUSIONS: The heterozygous inactivating mutation of the calcium receptor gene of this family is accompanied by mild increases in parathyroid gland x weight and diffuse parathyroid hyperplasia with possibly secondary genetic events causing nodule formation. Radical parathyroid resection is advocated in this hypercalcemic disorder, which may represent an intermediary stage between primary hyperparathyroidism and familial hypocalciuric hypercalcemia.     

Multiple parathyroid adenomas: report of thirty-three cases

An increasing number of patients with primary hyperparathyroidism are found to have two or three enlarged parathyroid glands. Of 865 patients successfully operated on by one surgeon (J.N.A.), multiple enlarged parathyroid glands (adenomas) were found and resected in 33 cases (3.8%), with resulting normocalcemia lasting from 1 to 22 years (mean 5.8). Twenty-nine patients had two adenomas and four had three adenomas. In 28 patients the multiple adenomas were synchronous. Twenty-five patients underwent removal of all of the enlarged parathyroid glands in one operation; in three patients one adenoma was removed, reoperation for persistent hypercalcemia was performed, and a second adenoma was resected with cure. In five patients one adenoma was removed, normocalcemia ensued for 3 to 18 years, and a second (metachronous) adenoma occurred and was resected successfully. Although 10 of 70 enlarged parathyroid glands removed were labeled hyperplasia, cure in all but one of our patients by selective resection of only enlarged parathyroid glands emphasizes the unreliability of histologic criteria in differentiating between parathyroid adenoma and hyperplasia. Based on this study, we support the existence of multiple adenomas and advocate removal of only macroscopically enlarged parathyroid glands in patients with primary hyperparathyroidism.     

Irradiation as an etiologic factor in tumours of the thyroid, parathyroid and salivary glands

Irradiation to the head and neck region, usually of low dosage, results in an increased frequency of thyroid, parathyroid and salivary gland tumours. The authors have reviewed their experience with these tumours. Fifty of 475 patients with carcinoma of the thyroid had received previous irradiation. Papillary or mixed papillar-follicular carcinoma occurred most commonly. Eleven of 100 patients with primary hyperparathyroidism had been irradiated and had a parathyroid adenoma. Twenty of 662 patients with salivary gland tumours had previously been irradiated. Mucoepidermoid carcinoma was the most common tumour. Patients who have been irradiated and have a palpable abnormality of the thyroid or the salivary glands should be treated surgically. The various noninvasive tests are of little value in distinguishing between a benign and a malignant tumour. Those with hypercalcemia, considered to be due to primary hyperparathyroidism, should be treated by exploration of the neck, identification of the four parathyroid glands and excision of an adenoma with biopsy of the three remaining glands. If more than one gland is abnormal, a subtotal parathyroidectomy is recommended.     

The problems encountered in the surgical management of primary hyperparathyroidism.

The problems encountered in the diagnosis and treatment of primary hyperparathyroidism were studied in 69 cases. The accuracy of imaging for hyperplasia was less than that for adenoma or carcinoma and the major causes for multiple operations were a failure to locate the four glands and mediastinal adenoma. The intravenous administration of high doses of calcitonin could reduce the serum calcium level of patients in hypercalcemic crisis. Carcinoma required ipsilateral modified radical neck dissection because of lymph node metastases, and non-medullary thyroid carcinoma was often associated with primary hyperparathyroidism. We found removal of the parathyroid adenoma and biopsy or extirpation of only one macroscopically normal gland to be a fully satisfactory procedure after bilateral neck exploration and attempting to identify at least four glands.     

The problems encountered in the surgical management of primary hyperparathyroidism

The problems encountered in the diagnosis and treatment of primary hyperparathyroidism were studied in 69 cases. The accuracy of imaging for hyperplasia was less than that for adenoma or carcinoma and the major causes for multiple operations were a failure to locate the four glands and mediastinal adenoma. The intravenous administration of high doses of calcitonin could reduce the serum calcium level of patients in hypercalcemic crisis. Carcinoma required ipsilateral modified radical neck dissection because of lymph node metastases, and non-medullary thyroid carcinoma was often associated with primary hyperparathyroidism. We found removal of the parathyroid adenoma and biopsy or extirpation of only one macroscopically normal gland to be a fully satisfactory procedure after bilateral neck exploration and attempting to identify at least four glands.     

Clinical and experimental advances in sporadic primary hyperparathyroidism

Primary hyperparathyroidism (HPT) has shown prevalence of up to 3% among elderly women in Nordic health screening surveys, and is increasingly diagnosed in patients with diffuse neuromuscular or psychiatric symptoms. Primary HPT, even with mild hypercalcemia, is associated with increased mortality risk, mainly from cardiovascular disease. Despite the efficacy of new methods, reliable histopathologic distinction between adenomatous and hyperplastic parathyroid disease may still be difficult, and indeed circumstantial evidence suggests that adenoma and chief cell hyperplasia are not always distinctly separate pathophysiologic entities. Irrespective of symptoms, the hyperplasia is associated mainly with mild to moderate hypercalcemia, and may thus constitute an early form of HPT. A more liberal attitude to surgery in primary HPT would increasingly extend treatment to less clear-cut cases. The demonstration by monoclonal antiparathyroid antibodies of a specialized calcium receptor mechanism on the surface of parathyroid cells and its reduced expression in pathologic parathyroid tissue seems to explain defective parathyroid cell function and ensuing hypercalcemia in HPT. These antibodies appear to offer new prospects in parathyroid histopathology and research.     

Surgical findings and results of subtotal and total parathyroidectomy in hypercalcemic patients with uremic hyperparathyroidism

Surgical and histopathologic findings and results of subtotal resection and total parathyroidectomy with autotransplantation were evaluated in 82 hypercalcemic patients with uremic hyperparathyroidism. The mean preoperative serum calcium concentration was 2.89 mM, and the highest values were associated with more rapidly progressing hypercalcemia. Despite greatly increased total weight of the parathyroid tissue (mean 1,509 mg), 34 patients had one to five normal-sized parathyroid glands. The incidence of such glands decreased with total gland weight. Nodular hyperplasia was found in 74% of the patients, and was characterized by considerable intraindividual size difference, while diffuse hyperplasia was associated with more moderate and symmetric glandular enlargement. During follow-up averaging 4.5 years, the incidence of persistent or recurrent hypercalcemia was slightly higher after subtotal than after total parathyroidectomy (11 and 11%, vs. 9 and 7%). Biochemical and/or radiologic signs of parathyroid bone disease were present in 36 (44%) of the patients before neck exploration and normalized postoperatively in all but seven. The outcome of parathyroid surgery thus was favorable in uremic patients with hypercalcemic hyperparathyroidism.     

Surgery for parathyroid adenoma and hyperplasia: Relationship of histology to outcome

Recent histopathologic evidence challenges the teaching that enlargement of a solitary parathyroid gland is invariably caused by an adenoma, whereas multiple gland enlargement results from hyperplasia. We have re-examined the parathyroid tissue obtained from 152 consecutive patients undergoing surgery for primary hyperparathyroidism and compared it with their clinical outcome. Our approach was to excise enlarged glands and biopsy the remainder. In 124 patients (82%) at least three glands were biopsied or removed. The ratio of adenoma to hyperplasia was reversed by our histologic re-examination; adenomas were found in only 27 patients (25 single, two double), whereas hyperplasia was found in 117 patients (one gland, 87 patients; two glands, 16 patients; three glands, five patients; four glands, nine patients). Normal tissue only was reported in eight patients. During a 2-year follow-up, five patients (3%) developed hypocalcemia and none developed recurrent hypercalcemia. Our results indicate that a full neck exploration with removal of all enlarged glands is more important than the histologic diagnosis in planning a successful surgical strategy for primary hyperparathyroidism.     

Tertiary hyperparathyroidism after renal transplantation: operative indications

A retrospective analysis of our renal transplant population between 1981 and 1987 was undertaken to study the natural history of posttransplant hypercalcemia and to review indications and recommendations regarding the timing of parathyroidectomy. During this period, 1158 renal transplant procedures were performed in 1025 patients, with 819 allografts (71%) functioning currently. Posttransplant hypercalcemia greater than 10.5 mg/dl was associated with a longer duration of dialysis and developed in 227 patients, with onset of hypercalcemia occurring in 90% of these patients by 1 year. In 69% of these patients, spontaneous resolution of the hypercalcemia occurred between 6 months and 7 years after transplantation. A total of 42 patients with asymptomatic hypercalcemia are currently being followed up, with a mean serum calcium level of 11.0 +/- 0.41 mg/dl and a mean follow-up interval of 3.3 +/- 1.6 years since transplantation. Nine symptom-free patients with moderate hypercalcemia (12.0 to 12.4 mg/dl) more than 1 year after transplantation were identified. Five of these patients had spontaneous resolution of the hypercalcemia between 2 and 7 years. Fifteen patients with posttransplant hyperparathyroidism (6.6%) required parathyroidectomy--11 for symptomatic and four for asymptomatic hyperparathyroidism. One patient had symptomatic hyperparathyroidism despite the presence of normocalcemia. One symptom-free patient with significant hypercalcemia (serum calcium level, 14.7 mg/dl) underwent parathyroidectomy 3 months after transplantation. The remaining three symptom-free patients had serum calcium determinations of greater than or equal to 12.5 mg/dl more than 1 year after renal transplantation. Patients with pretransplant and posttransplant hypercalcemia required parathyroidectomy more frequently than did patients with only posttransplant hypercalcemia (18% versus 3.0%; p less than 0.001). An unusual finding was the occurrence of a single adenoma in two patients, which represents sporadic primary hyperparathyroidism in the patient undergoing renal transplantation rather than tertiary hyperparathyroidism. We recommend a conservative approach to posttransplant hypercalcemia, with surgery reserved for patients with symptomatic disease and patients with asymptomatic persistent hypercalcemia greater than or equal to 12.5 mg/dl more than 1 year after transplantation.     

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.     

Long-term follow-up of patients with tertiary hyperparathyroidism treated by resection of a single or double adenoma

OBJECTIVE: To determine whether patients with tertiary hyperparathyroidism due to single- or two-gland disease undergoing limited resection have similar long-term outcomes compared with patients with hyperplasia undergoing subtotal or total parathyroidectomy. SUMMARY BACKGROUND DATA: Tertiary hyperparathyroidism occurs in less than 2% of patients after renal transplantation. Approximately 30% of these cases are caused by one or two hyperfunctioning glands. Nevertheless, the standard operation for this disease has been subtotal or total parathyroidectomy with autotransplantation. METHODS: Seventy-one patients underwent surgery for tertiary hyperparathyroidism. At the time of surgery, 19 patients who had a single or double adenoma underwent limited resection of the enlarged glands only (adenoma group). The remaining 52 patients with three- or four-gland hyperplasia had subtotal or total parathyroidectomy with implantation (hyper group). Long-term cure rates between the two groups were compared. RESULTS: In the adenoma group, 7 patients had a single adenoma and 12 underwent resection of a double adenoma. In the hyper group, 49 patients had subtotal and 3 had total parathyroidectomies. After surgery, 70 of 71 patients (99%) were cured of their hypercalcemia. The incidence of postoperative transient hypocalcemia was significantly higher in the hyper group (27% vs. 5%). No patients in either group had permanent hypocalcemia requiring long-term supplementation. With up to 16 years of follow-up, there have been no recurrences in the adenoma group, whereas three patients (6%) in the hyper group have had recurrent or persistent hyperparathyroidism. CONCLUSIONS: Patients with tertiary hyperparathyroidism who underwent limited resection of a single or double adenoma only had equivalent long-term cure rates compared with patients undergoing more extensive resections. Therefore, the authors recommend in patients with tertiary hyperparathyroidism and enlargement of only one or two parathyroid glands that the resection be limited to these abnormal glands only.     

Continuing evolution in the operative management of primary hyperparathyroidism.

During the past several decades the operation for primary hyperparathyroidism at The University of Chicago, Ill, has changed from subtotal parathyroidectomy for all patients to removal of an adenoma with performance of biopsies of all other glands to bilateral neck exploration, resection of the adenoma, and performance of fewer biopsies of normal glands. During the 1980s, 308 operations were performed; 288 patients underwent first operations. Two hundred forty-five (85.1%) of these patients had an adenoma and forty-three (14.9%) had hyperplasia (multiglandular disease); none had a carcinoma. Resolution of hypercalcemia was achieved in 281 patients (97.5%); seven patients experienced failed explorations. The early cure was the same whether or not preoperative localization studies were performed. Nineteen patients underwent 20 reoperative parathyroidectomies during this period. Preoperative localization studies, done in 16 (80%) of 20 cases, were very helpful. Ninety percent of patients with abnormal parathyroid glands in their neck or mediastinum were cured with their initial reoperation.     

Treatment of severe hypercalcemia due to refractory hyperparathyroidism in renal transplant patients with the calcimimetic agent cinacalcet

Calcimimetic agents increase the sensitivity of calcium sensing receptors of parathyroid glands and suppress both serum calcium levels and parathyroid hormone. There are still limited data on the treatment of renal transplant patients with severe hypercalcemia and hyperparathyroidism with calcimimetics (cinacalcet). We describe two such renal transplant patients with chronic kidney disease Stage 3 who presented with persistent hypercalcemia (serum calcium 11.5-12 mg/dl) and refractory hyperparathyroidism (iPTH 194-547 pg/ml). Control of hypercalcemia with cinacalcet (serum calcium <10 mg/dl) resulted also in an improvement of hyperparathyroidism, but with a slower rate than that of the lowering of serum calcium. Addition of a vitamin D analog together with the calcimimetic agent resulted in faster control of the resistant hyperparathyroidism in both patients (iPTH <145 pg/ml) with clinical improvement and without any side effect. It seems that this new agent will improve our clinical approach of renal bone disease permitting a more integrated and successful treatment of hyperparathyroidism and its consequences on patients with chronic kidney disease.     

Ectopic thymic parathyroid adenoma and vitamin D deficiency rickets: a 5-year-follow-up case report and review of literature

Sixteen patients with primary hyperparathyroidism presenting as rickets have so far been reported in the English literature. However, no report of an ectopic thymic parathyroid adenoma presenting as rickets has been published. We report a 14-year-old Caucasian American, wheelchair-ridden male who presented with signs and symptoms suggestive of vitamin D deficiency rickets subsequently confirmed by laboratory and radiological findings. Following the intramuscular administration of 125,000 U ergocalciferol (vitamin D2), he developed hypercalcemia with persistently elevated parathyroid hormone (PTH) levels suggestive of primary hyperparathyroidism. Sestamibi scan demonstrated significant uptake in the superior chest, without uptake at the normal parathyroid glands location. Surgical exploration revealed normal parathyroid glands and a thymic mass, which was removed and confirmed by pathology to be a parathyroid adenoma. With subsequent oral ergocalciferol solution and calcium carbonate therapies, the patient's symptoms resolved, blood chemistries normalized, and radiological evidence of rickets significantly improved. To our knowledge, this is the first case of an ectopic thymic parathyroid adenoma in a patient presenting with rickets. Our patient demonstrates that hyperparathyroidism-induced hypercalcemia may be masked by severe vitamin D deficiency. Prolonged treatment with ergocalciferol after removal of the parathyroid adenoma was necessary to normalize iPTH and replenish vitamin D store.     

Long-term evaluation of patients with primary parathyroid hyperplasia managed by total parathyroidectomy and heterotopic autotransplantation.

Since 1973, we have performed total parathyroidectomy and forearm parathyroid autotransplantation in 36 patients with generalized (four gland) primary parathyroid hyperplasia. Twenty (56%) patients had nonfamilial parathyroid hyperplasia (NFPH) and 16 (44%) patients had familial parathyroid hyperplasia (FPH). Twenty-one patients (Group A) were undergoing operation for the first time and 15 (Group B) were having either second, third or fourth re-explorations for persistent hyperparathyroidism. All patients in Group A and nine patients in Group B had parathyroid resection and immediate autotransplantation as a single procedure. Six Group B patients had hyperfunctioning parathyroid tissue resected, cryopreserved, and subsequently grafted when it was evident that they had been rendered aparathyroid. A sustained differential elevation (13.7 fold +/- 2.7) of parathyroid hormone was detected in the antecubital vein of the grafted compared to the nongrafted arm in 35 (97%) patients. Two (5.6%) of the 36 patients (both with FPH; one Group A and one Group B) required permanent oral calcium and vitamin D replacement therapy and one (3%) patient (NFPH: Group A) had persistent hypercalcemia postoperatively, presumably due to a supernumerary gland. The remaining 33 (92%) patients became normocalcemia after surgery and 23 (70%) of them remained so. Ten (30%) of the 33 patients developed recurrent graft dependent hyperparathyroidism. Eight patients were from the group with FPH (8/14, 57%) and two were from the group with NFPH (2/19, 11%)(FPH vs. NFPH, p < 0.005). Because of symptoms of hypercalcemia or a serum calcium concentration exceeding 11 mg/dl, partial graft resection was performed in five patients and four became normocalcemic. Patients with generalized primary parathyroid hyperplasia may be difficult to cure, especially if the disease is familial. The technique of total parathyroidectomy and heterotopic autotransplantation of fresh or cryopreserved parathyroid tissue offers distinct advantages over alternative techniques.     

Milk alkali syndrome. Does it exist and can it be differentiated from primary hyperparathyroidism?

Four patients with milk-alkali syndrome (MAS) presented with many of the characteristics of primary hyperparathyroidism including hypercalcemia, low or normal serum phosphorus levels, normal or increased urinary calcium levels, and inappropriately high or elevated serum parathyroid hormone levels. These laboratory findings differ from those classically described in MAS, i.e., hypercalcemia without hypercalciuria and a normal or high plasma phosphate level. Because the serum calcium level failed to return to normal after two weeks of hydration and a low calcium diet, and because of the inability to distinguish this syndrome from primary hyperparathyroidism, two of the four patients underwent neck exploration. Four normal parathyroid glands were histologically proven in each, and at autopsy in a third patient, there was no evidence of parathyroid hyperplasia or adenoma. Hypercalcemia eventually resolved in all patients with a low-calcium diet for as long as six months. Of the several features of MAS, hypercalcemia, alkalosis in the presence of azotemia, a history of increased calcium and alkali intake, and a response to dietary calcium restriction are helpful in differentiating this syndrome from primary hyperparathyroidism. Laboratory tests in patients with MAS may be confusing and the return to normocalcemia in response to a calcium deficient diet may be delayed.