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Query: UMLS:C0020437 (hypercalcemia)
 10,293 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Extracellular fluid calcium is a tightly controlled variable. Hypoparathyroid state may result in profound calcium imbalance and moderate to severe hypocalcaemia. During 1974-89, 108 cases of hypoparathyroidism (97 post-surgical and 11 idiopathic) were seen. In the post-thyroidectomy group, 83 cases (85%) presented with acute transient hypocalcaemia with spontaneous recovery within 7-10 days. Chronic hypoparathyroidism was seen in 25 cases (14 post-surgical and 11 idiopathic). Convulsions resembling epileptic fits were seen in 9 cases (36%). Pseudopapilloedema was seen in three cases presenting with fits. The administration of phenobarbitone and dilantin aggravated convulsions in 9 patients. The other manifestations were psychiatric illness, cataract and calcification of basal ganglion. Biochemical findings included persistent hypocalcaemia with normal or raised serum phosphorus and lowered daily urinary excretion of calcium. Twenty three of 25 chronic hypoparathyroid cases were treated with vitamin D3 (1-3 mg/day) and calcium supplements (600-1000 mg/day)while 1 alfa-calcidol or calcitriol was used in two patients. Four patients receiving treatment with vitamin D3 developed transient hypercalcaemia with raised plasma levels of 25 hydroxy-vitamin D3. They responded to a reduction in dosage of vitamin D3. One patient was later changed over to 1-alfa-calcidol and another to calcitriol.
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PMID:Calcium imbalance in hypoparathyroidism. 130 51

Plasma concentrations of PTH are much lower for a given calcium or phosphorus level in patients with familial benign hypercalcemia (FBH, or familial hypocalciuric hypercalcemia) than in those with primary hyperparathyroidism; these and other data suggest that there might be tissue hypersensitivity to PTH in FBH. To test this hypothesis, we have used cultured dermal fibroblasts from abdominal skin biopsies of six patients with FBH and six age- and sex-matched controls as surrogate PTH-responsive tissues. Cells in 24-well plastic plates were exposed to vehicle, human PTH-(1-34) (10(-10)-10(-7) M), prostaglandin E2 (10(-6) M), or isoproterenol (10(-4) M) for 10 min in the presence of isobutylmethylxanthine, and cellular cAMP was determined by RIA. All cells responded to PTH with dose-dependent increases in cAMP, and all responded strongly to prostaglandin E2 and isoproterenol. There were no consistent or significant differences between control and FBH fibroblasts in maximal responses to the three agonists, and half-maximal stimulation was achieved with about 10(-9) M PTH in both normal and FBH cells. These data are not consistent with increased tissue sensitivity to PTH in FBH.
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PMID:Cyclic adenosine 3',5'-monophosphate responses to parathyroid hormone, prostaglandin E2, and isoproterenol in dermal fibroblasts from patients with familial benign hypercalcemia. 171 Jun 22

We evaluated the incidence of hypo- versus hypercalcemia and hypo- versus hyperphosphatemia in a survey of 158 patients with malignancy; 55/158 had bone metastases. When serum calcium levels were corrected for albuminemia, the incidence of hypo- and hypercalcemia was respectively 10.8% and 10.1%. Hypophosphatemia was found in 29.7% patients, hyperphosphatemia in 2.5%. The incidence was slightly different in presence of bone metastases. Hypocalcemia and hypophosphatemia prevailed in osteoblastic metastases and hypercalcemia in osteolytic metastases. The incidence of hypocalcemia and hypophosphatemia in malignancy was therefore surprisingly high, even apart from the presence of bone metastases. Both hypo- and hypercalcemia were associated with elevated serum alkaline phosphatase levels. Moreover, a calcium-phosphorus product reduction was observed in osteoblastic metastases, suggesting a condition of secondary hyperparathyroidism.
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PMID:A hospital survey of hypocalcemia and hypophosphatemia in malignancy. 174 50

Calcium carbonate is frequently used in large doses as a phosphorus binder in hemodialysis patients, which often results in hypercalcemia. In most studies in which calcium carbonate is prescribed to control serum phosphorus levels the patients are not given calcitriol. However, calcitriol may be necessary for suppression of parathyroid hormone. The risk of hypercalcemia when calcium supplements are used in conjunction with calcitriol has not previously been examined in detail. We reviewed the charts of 74 hemodialysis patients (119 patient dialysis years) to determine the relationship of serum calcium to calcitriol, calcium therapy, and PTH levels. Twenty-eight patients (38%) were hypercalcemic at some point. Calcitriol therapy significantly increased the risk of hypercalcemia, independently of calcium therapy (p = 0.032). However, patients on a low dose of calcitriol were more than twice as likely to be hypercalcemic than patients on higher doses. Mean PTH levels were lower in the patients on the lower doses of calcitriol, indicating less severe hyperparathyroid disease. We conclude that hypercalcemia is a common complication in hemodialysis patients on calcitriol and calcium carbonate. Whether lowering the dialysate calcium, as suggested by other investigators, will successfully decrease the risk of hypercalcemia without worsening hyperparathyroidism remains to be determined.
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PMID:Iatrogenic hypercalcemia in hemodialysis patients. 175 77

The differential diagnosis of hypercalcemia has expanded to over 25 separate disease states, with primary hyperparathyroidism and malignancy accounting for 80-90% of all hypercalcemic patients. Primary hyperparathyroidism comprises the majority of hypercalcemic patients among the ambulatory population, but malignancy accounts for up to 65% of such patients in the hospital. Factors favoring primary hyperparathyroidism include a family history of hyperparathyroidism or multiple endocrine neoplasia, a history of childhood radiation to the head and neck, the postmenopausal state, a history of renal calculi or peptic ulcer, hypertension, the induction of hypercalcemia by thiazides, or an asymptomatic patient with a prolonged, stable mild hypercalcemia. The usefulness of the serum calcium, parathyroid hormone, chloride, phosphorus, serum 25-OHD, and 1,25-(OH)2D, and urinary calcium in the differential diagnosis of hypercalcemia is discussed. The pitfalls of an excessive reliance on the serum PTH in diagnosing hyperparathyroidism are stressed. The discriminant values of the serum calcium, chloride, phosphorus, and parathyroid hormone are explored, with the serum parathyroid hormone, chloride, and calcium proving most useful in separating primary hyperparathyroidism from other forms of hypercalcemia. Multivariate discriminant analysis using the serum calcium, phosphorus, and chloride and the hematocrit achieves an accuracy of 95-98% and is the most economical method of identifying hyperparathyroidism. The addition of the amino-terminal or intact PTH assay increases the accuracy to 99% and is essential in the presence of renal insufficiency.
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PMID:Differential diagnosis of hypercalcemia. 176 70

We have previously shown the synergistic interaction between fructose and magnesium (Mg) deficiency on renal calcification of female rats. The purpose of the present study was to determine whether the calcification formed in the kidneys of female rats fed an Mg-deficient fructose diet is due to phosphate or oxalate precipitates of calcium. The rats were divided into two dietary groups: fructose without Mg and starch with Mg. Rats were fed their respective diets for 9 weeks, and 24 h urine was collected for measuring urinary output, pH, Mg and calcium (Ca). The rats were then fasted overnight and after decapitation, blood was immediately collected for measuring plasma Ca and Mg, and the kidneys were removed. Left kidneys were used to determine their Mg and Ca contents, and right kidneys were dissected and fixed in neutral buffered formalin. Formalin-fixed specimens for microscopy were processed in paraffin using conventional procedures. Histochemical analysis was conducted by staining serial paraffin sections with haematoxylin, eosin, PAS-Schiff, alcian blue and trichrome. The sections were stained by the von Kossa method for calcium phosphate and by the silver hydroperoxide method for calcium oxalate. Only calcium phosphate was detected in the corticomedullary junction of the kidneys of female rats fed Mg-deficient fructose. The hypercalcaemia, hypercalciuria, and hypomagnesuria observed in the fructose group may cause calcium phosphate crystallization. A possible mechanism for the interaction between magnesium deficiency, fructose and oestrogen may be through parathyroid hormone which increases tubular fluid Ca and phosphorus (TF[Ca]x[P]). Further studies are required to prove the mechanism proposed here.
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PMID:Fructose precipitates calcium phosphate in the kidneys of female rats fed magnesium-deficient diets. 179 51

Prevention of bone disease associated with impairment of the renal function is desirable. Attempts at such prevention inevitably also embrace prevention of the extraosseous consequences of autonomous hyperparathyroidism, such as the effects of hypercalcaemia, need for parathyroid surgery, and, perhaps, toxic effects of the parathyroid hormone. Strategies for prevention in early, moderate, and end-stage renal failure are reviewed and discussed with particular reference to dietary phosphorus restriction, use of gut phosphorus binders, control of acidosis, calcium supplementation, use of oral and intravenous calcitriol, and use of synthetic analogues of 1,25-dihydroxyvitamin D3. The onset of severe renal osteodystrophy can be delayed. Early attempts at prevention are logical, but we do not know whether these will reduce the need for parathyroid surgery or will make patients feel better or live longer. The costs of prophylaxis--both financial and in terms of incidence and severity of complications--remain to be defined. An individual approach to each patient with renal impairment seems at present appropriate.
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PMID:Prevention of renal osteodystrophy. 181 86

The aim of the study was the evaluation of the efficacy of calcium carbonate (CaCO3) in the control of serum phosphorus level in children with ESRD. Sixteen patients (group I) were evaluated retrospectively, 25 pts (group II) were observed prospectively. The pts from group I were treated with CaCO3 (100-800 mg/kg/day) with or without Al(OH)3 and with different doses of DHT. The pts from group II were treated with CaCO3 and DHT without Al(OH)3 but some of them had obtained Al(OH)3 in the past. The doses of CaCO3 were individually adjusted to maintain the serum calcium level 5.0-5.5 mEq/l. In the pts on CAPD evaluated retrospectively the control of serum phosphorus level was better and episodes of hypercalcemia were more frequent than in the pts on HD. Neither the concomitant use of Al(OH)3 with CaCO3 nor varying the dosage of DHT within assumed range influenced serum phosphorus level. The differences in serum phosphorus level and in the frequency of episodes of hypercalcemia in pts in group II were less obvious then in group I. It may depend on more precise adjustment of CaCO3 doses to the individual needs of these pts. The episodes of hypercalcemia in the group II were more frequent in pts who received Al(OH)3 in the past.
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PMID:Calcium carbonate as a phosphate binder in children on continuous ambulatory peritoneal dialysis and hemodialysis. 184 16

A 40-year-old woman was admitted because of long-lasting asymptomatic hypercalcaemia. About 2 years earlier she underwent thyroidectomy and further 131 I therapy because of well-differentiated non medullary thyroid carcinoma. On admission biochemical data and hormonal values (serum calcium, serum phosphorus, i-PTH) were consistent with primary hyperparathyroidism; ultrasonography, computed tomography, thallium-technetium scintiscanning disclosed right paratracheal mass; on surgical procedure a right parathyroid adenoma was removed. The coexistence of non medullary thyroid carcinoma and primary hyperparathyroidism is rare: the prior 131 I therapy might be linked to subsequent development of parathyroid adenoma.
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PMID:An association of primary hyperparathyroidism and non medullary thyroid carcinoma. 188 51

The enzyme carbonic anhydrase has been suggested as a critical participant in osteoclast-mediated bone resorption. In humoral hypercalcemia of malignancy (HHM) intense osteoclastic bone resorption is principally responsible for the observed hypercalcemia. We therefore undertook to examine the effect of the carbonic anhydrase inhibitor acetazolamide on the hypercalcemia induced by the H500 Leydig cell tumor in Fisher rats, a well-described model of HHM. Acetazolamide treatment for 10 h at 10 mg/h resulted in a significant fall in serum calcium in the five drug-treated animals (14.2 +/- 0.9 to 11.5 +/- 0.1 mg/dl, p less than 0.05). Conversely, the six animals infused with vehicle alone showed a significant rise in serum calcium (12.5 +/- 0.5 to 13.8 +/- 0.1 mg/dl, p less than 0.05). At the end of the infusion, the acetazolamide-treated animals had a significantly lower mean serum calcium than those receiving vehicle alone (11.5 +/- 0.1 versus 13.8 +/- 0.1, p less than 0.05). There was no significant change in serum phosphorus, urine calcium, urine phosphorus, or nephrogenous cyclic AMP excretion between the two groups. Acetazaolamide and HTS 5-(3-hydroxybenzoyl)-2-thiophenesulfonamide, another carbonic anhydrase inhibitor, both significantly inhibited in vitro bone resorption induced by 5 X 10(-9) M 36Tyr(1-36)-PTHrP-amide (PTHrP, parathyroid hormone-related protein). Acetazolamide also inhibited the resorption induced by 10(-8) M (1-141)-PTHrP and 2.5 X 10(-9) M (1-74)-PTHrP. We conclude that acetazolamide is effective in lowering the serum calcium in animals with humoral hypercalcemia of malignancy. The data are consistent with the hypothesis that the mechanism of action for this effect is direct inhibition of osteoclast-mediated bone resorption.
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PMID:Treatment of humoral hypercalcemia of malignancy in rats with inhibitors of carbonic anhydrase. 196 58


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