Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0221002 (primary hyperparathyroidism)
 4,921 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Parathyroid carcinoma is one cause of primary hyperparathyroidism, a condition in which there is hypercalcemia and dysregulated hypersecretion of PTH. In normal, and in some neoplastic parathyroid cells, PTH secretion is mediated by the cell surface calcium-sensing receptor. We describe the first therapeutic use of a novel molecule, a calcimimetic, that has agonist action at the calcium-sensing receptor. A 78-yr-old man with parathyroid carcinoma was admitted with hypercalcemia, markedly elevated PTH, and a change in mental status. He was treated for 17 days with conventional therapy, which included saline hydration, furosemide, pamidronate, and calcitonin. This was ineffective, and on hospital day 18, calcimimetic at a dose of 50 mg, orally, every 6 h was added. On hospital day 25, the dose was increased to 100 mg, orally, every 6 h, and on hospital day 30, saline and furosemide were discontinued. He was discharged on hospital day 40. With several dose adjustments, he has been treated with monotherapy calcimimetic for over 600 days and has not required any other interventions for his parathyroid carcinoma. Mean daily precalcimimetic treatment values of serum ionized calcium and PTH were 1.83 mmol/L and 872 pg/mL, respectively. During hospitalization, at the lower dose of calcimimetic, calcium and PTH decreased to 1.67 mmol/L and 538 pg/mL; with the higher dose they further decreased to 1.51 mmol/L and 444 pg/mL. Since discharge, and despite increasing levels of PTH, serum calcium has remained high, but lower than the admission level and acutely responsive to changes in calcimimetic doses. This compound, a calcimimetic, the first of a new class of compounds with activity at the calcium-sensing receptor, has been used to treat a patient with parathyroid carcinoma. During 2 yr of treatment, no adverse clinical effects have been observed, and it appears to have been effective at controlling hypercalcemia.
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PMID:Treatment of hypercalcemia secondary to parathyroid carcinoma with a novel calcimimetic agent. 954 21

Multiple endocrine neoplasia type 2 (MEN 2) is a rare syndrome of medullary thyroid carcinoma (MTC) with pheochromocytoma and/or primary hyperparathyroidism (PHP), usually due to multigland hyperplasia. MEN 2 is associated with several RET protooncogene mutations. A 61-year-old woman with a family history of RET-positive MTC presented with a solitary thyroid nodule. Fine-needle aspiration biopsy was suspicious for neoplasm. Biochemical studies revealed basal hypercalcitoninemia (116 pg/mL [normal <26]) and PHP (serum calcium, 10.9 mg/dL; intact PTH, 113.2 pg/mL [10.0-65.0]). Pheochromocytoma screening was negative. A provisional diagnosis of MEN 2 was made, but at surgery, a single parathyroid adenoma was resected and frozen sections of several lymph nodes revealed papillary thyroid carcinoma (PTC). A total thyroidectomy was performed. Final histological diagnosis was PTC and parathyroid adenoma with no evidence of MTC. Postoperatively, RET mutation testing was positive. The basal calcitonin (CT) fell to 25 pg/mL, but peaked at 935 (normal <105) after pentagastrin infusion, consistent with occult MTC. After radioiodine ablation, CT decreased further. Octreotide scanning was negative. Faced with PHP, a thyroid nodule, and a family history of MTC, clinicians tend to diagnose MEN 2. This patient had a single parathyroid adenoma and nonmedullary thyroid cancer, which the literature actually suggests to be an association more frequent than MEN 2. Yet, there remains compelling data in favor of occult MTC, leaving open the possibility of an MEN 2 variant with the rare association of PTC.
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PMID:Papillary thyroid carcinoma, parathyroid adenoma, and unexplained hypercalcitoninemia: an unusual presentation of multiple endocrine neoplasia type 2A? 977 49

A 49 year-old Japanese woman had subjected enlargement of a cervical tumor, and also suffered two bone fractures in 2 years. The cervical tumor had enlarged further in the month prior to admission, becoming warm and tender. Endocrinological examination revealed that the serum intact PTH concentration was remarkably high at 400 pg/mL despite the low serum calcium concentration, and that the serum vitamin Ds concentration was decreased. Bone roentgenograms revealed severe osteolytic changes compatible with osteitis fibrosa cystica and a pathologic fracture of the humerus. Under a diagnosis of primary hyperparathyroidism, parathyroidectomy was performed, followed by fixation surgery for the pathologic fracture. Histologically, the cervical tumor was a parathyroid chief-cell adenoma with massive necrosis, and the bone pathology by iliac bone biopsy revealed the existence of osteomalacia. She was treated with calcium, vitamins D and K2 and calcitonin after the surgery. This case is a rare condition manifesting hypocalcemia with catastrophic osteoporosis under the coexistence of spontaneous infarction of parathyroid adenoma with osteomalacia, suggesting that the clinical features of hyperparathyroidism are modified by both the autoparathyroidiectomy and the existence of osteomalacia due to vitamin D deficiency.
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PMID:Hypocalcemia due to spontaneous infarction of parathyroid adenoma and osteomalacia in a patient with primary hyperparathyroidism. 1039 41

This study deals with the setting up of human serum calcitonin radioimmunoassay (hCT-RIA) using the high titer and specific antibody which was prepared by our own laboratory. The final dilution of the antibody titer was 1:1,200,000 when the binding rate of Bo/T was 30%. The antibody's affinity constant (Kd) was 2.25 x 10(11) L/M. No cross reaction was found between the antibody and the following eight different peptide hormones and proteins, viz.: TSH, T3, T4, ACTH, PTH, BGP, Insulin and Gastrin. The coefficients variation of intra and inter assay were 3.2% and 9.0%, respectively. The mean recovery rate of CT was 99.8%. The sensitivity of this assay was 9.4 pg/ml. The examination of this methodology showed that all its indices met the demands of RIA. There was no difference in the mean value of serum CT between the two sexes in 232 normal subjects, but the serum CT concentration in those aged of sixty and over of men and women, were much lower than those aged of fourty group. Mean CT concentration was low in the patients with primary osteoporosis, but were significantly higher in those suffering from medullary thyroid carcinoma, primary hyperparathyroidism crisis and chronic renal failure.
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PMID:[The setting up of human serum calcitonin radioimmunoassay and its clinical application]. 1045 98

Prolonged immobilization or physical inactivity has been shown to produce increased bone resorption due to enhanced osteoclastic activity and diminished bone formation. These skeletal changes are a typical complication in tetraplegic patients, who are at risk of developing hypocalcemia. Hypercalciuria is the most characteristic symptom. However, some patients develop hypercalcemia, which is infrequent in these patients, and the hypercalcemia can become a life-threatening complication. Until now, it has been unclear why a small percentage of immobilized patients develop hypercalcemia. Here we present a case of symptomatic hypercalcemia (serum calcium: 3.5 mM/l) following immobilization due to a critical illness polyneuropathy. The diagnosis could be established after malignant hypercalcemia, primary hyperparathyroidism, and other causes of hypercalcemia were excluded. Treatment with intravenous saline, furosemide, and calcitonin was not effective in lowering serum calcium. Treatment with pamidronate (Aredia) was successful and reduced the serum calcium to normal values.
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PMID:[Immobilization hypercalcemia as a complication of polyneuropathy]. 1099 16

Parathyroid hormone (PTH), especially intact human PTH [hPTH(1-84)] and its various fragments [hPTH(1-31), (1-34), (1-36), (1-38) and their modifications], has been used for the treatment of osteoporosis over the last 10 years. Although chronic continuous excess of PTH markedly increases bone resorption, as seen in the typical example of primary hyperparathyroidism and osteitis fibrosa generalisata, intermittent PTH administration has been found to stimulate bone formation in animals, providing a basis for the use of PTH as a therapeutic agent for osteoporosis. In addition to dramatically increasing trabecular bone density and also sustaining cortical bone density, PTH administration increases bone strength and reduces the fracture rate, despite occasional increases in cortical porosity. Administration of PTH in combination with antiresorptive agents such as estrogen, calcitonin, vitamin D and bisphosphonates augments its effect. Because of its bone anabolic action, PTH is expected to be effective for osteoporosis in those of advanced age with suppressed bone remodelling, which might not respond favourably to antiresorptive agents.
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PMID:Parathyroid hormone in the treatment of osteoporosis. 1170 47

The etiology, pathophysiology, and diagnosis of hypercalcemia associated with malignant diseases are discussed. In humans, calcium is controlled by three mechanisms: parathyroid hormone, which regulates bone resorption and renal reabsorption of calcium; calcitonin, an antagonist of parathyroid hormone; and cholecalciferol, which regulates calcium absorption from the gastrointestinal tract. Hypercalcemia of malignancy (HCM) results primarily from increased bone resorption by osteoclasts and, to a lesser extent, from increased renal tubular reabsorption. In most tumors, parathyroid hormone-related protein (PTHrP) is the primary mediator of calcium. PTHrP stimulates increased bone resorption by osteoclasts. This stimulation also activates transforming growth factor-beta (TGF-beta), which stimulates tumor cells, thus perpetuating the cycle. Hypercalcemia is usually defined as a serum calcium concentration greater than 12 mg/dL, corrected for the serum albumin concentration. In diagnosing HCM, it is important to rule out other causes of hypercalcemia, such as primary hyperparathyroidism.
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PMID:Overview of hypercalcemia of malignancy. 1175 5

Since 1969 to 2000 twenty one patients from 16 families with syndrome of multiple endocrine neoplasia (MEN) type 2 were examined. Medullary cancer of the thyroid gland (MCTG) was diagnosed in 18 patients, pheochromocytoma--in 15 (in 13 of them--two-sided), primary hyperparathyroidism--in 2. In 9 patients from 5 families syndrome MEN 2 was confirmed genetically (mutation in codon 634 of 11th exon RET in 7 patients with MEN 2a and in codon 918 in 2 patients with MEN 2b). None of the patients had extraadrenal pheochromocytoma, in 9 (60%) patients multicentric tumors within one adrenal gland were diagnosed. All the 18 patients with MCTG underwent extrafascial thyroidectomy with removal of fat and lymph nodes of paratracheal zone, 9 patients--one-sided (6) or two-sided (3) removal of fat and lymph nodes of lateral triangle of neck. Prophylactic thyreoidectomy was performed in 11-year old patient with genetically verified MEN 2a and without topical data of MCTG, 2 patients of 3 and 19 years of age with genetically verified MEN 2 are to undergo prophylactic thyroidectomy. Prophylactic thyroidectomy is necessary in the presence of genetic disorders in members of families with MEN 2 despite absence of structural changes in thyroid gland. Level of basal and stimulated calcitonin may be used as marker of recurrence or metastatic growth only. In MEN 2 after organ-saving operation rate of true recurrence of tumor is high because of genetic damage of medullary layer of adrenal gland.
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PMID:[Diagnosis and treatment of syndrome of multiple endocrine neoplasia type 2]. 1241 13

Seventy-four postmenopausal women with nonpathological hip fracture were recruited to a study in which they were compared for lifetime factors, some biochemical measurements of bone metabolism, and bone mineral density (BMD), with 40 age-adjusted controls without fracture. The fracture patients were less independent; their walking ability was weaker; their vision was poorer; they had more general diseases (strokes, diabetes, malignant diseases, heart and vascular diseases); more of them had had deliveries; and they were using significantly more loop diuretics, and antidepressant, neuroleptic, and diabetes drugs than the controls. Thirty-seven patients and 19 controls were excluded from the statistical comparison of BMD and the biochemical measurements of bone metabolism because they had had treatments with calcium, vitamin D, bisphosphonates, estrogens, calcitonin, or corticosteroids, and one fracture patient was excluded for primary hyperparathyroidism. The BMD of the upper femur was significantly lower in the fracture group compared with the control group. Serum total calcium (S-Ca) and serum vitamin D (S-25-(OH)-D) were significantly lower and the levels of calcitonin (S-CT) significantly higher in the fracture group than in the control group, but none of the bone formation markers showed significant differences between the study groups. A comparison of patients with cervical and trochanteric fractures showed BMD to be significantly lower in the upper femur in the trochanteric fracture group. There were no significant differences in the biochemical measurements (with the exception that S-CT was higher in the cervical fracture group), nor in the lifetime factors between the fracture types. In conclusion, some lifetime factors and low S-Ca, low S-25-(OH)-D, high S-CT, and low BMD of the upper femur seem to be related to the risk of hip fracture, and low BMD and low S-CT seem to be related to the trochanteric fracture type in postmenopausal women.
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PMID:Characteristics of lifetime factors, bone metabolism, and bone mineral density in patients with hip fracture. 1243 65

Hypercalcemia is a disorder commonly encountered by primary care physicians. The diagnosis often is made incidentally in asymptomatic patients. Clinical manifestations affect the neuromuscular, gastrointestinal, renal, skeletal, and cardiovascular systems. The most common causes of hypercalcemia are primary hyperparathyroidism and malignancy. Some other important causes of hypercalcemia are medications and familial hypocalciuric hypercalcemia. An initial diagnostic work-up should include measurement of intact parathyroid hormone, and any medications that are likely to be causative should be discontinued. Parathyroid hormone is suppressed in malignancy-associated hypercalcemia and elevated in primary hyperparathyroidism. It is essential to exclude other causes before considering parathyroid surgery, and patients should be referred for parathyroidectomy only if they meet certain criteria. Many patients with primary hyperparathyroidism have a benign course and do not need surgery. Hypercalcemic crisis is a life-threatening emergency. Aggressive intravenous rehydration is the mainstay of management in severe hypercalcemia, and antiresorptive agents, such as calcitonin and bisphosphonates, frequently can alleviate the clinical manifestations of hypercalcemic disorders.
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PMID:A practical approach to hypercalcemia. 1522 42


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