1,25-Dihydroxyvitamin D production after stimulation with synthetic human parathyroid hormone (1-34) in hypoparathyroid and renal tubular disorders

1,25-dihydroxyvitamin D production in response to two successive infusions of synthetic active 1-34 fragment of human PTH [hPTH-(1-34)] was evaluated in order to develop an understanding of the vitamin D metabolism and the rationale of vitamin D therapy in calcium disorders. Five normal controls, six hypoparathyroid patients, two patients with hypophosphatemic vitamin-D-resistant rickets, one patient with Lowe's synd. and one patient with primary Fanconi's synd. were investigated, and the following results were obtained. All normal controls showed a significant increase in serum 1,25(OH)2D[43 +/- 3.8 (m +/- SEM, n = 5, basal), 53 +/- 4.3 (three hours after the first PTH infusion), 65 +/- 7.7 (six hours) and 66 +/- 4.4 (nine hours) pg/ml]. All patients with PTH-deficient hypoparathyroidism showed a significant increase in serum 1,25(OH)2D, and serum 1,25(OH)2D values were within the normal range after hPTH-(1-34) stimulation. Serum 1,25(OH)2D remained low after hPTH-(1-34) infusions in a patient with pseudohypoparathyroidism type I who showed a significant increase in this value after infusion of dibutyryl cyclic AMP. On the other hand, a patient with normocalcemic pseudohypoparathyroidism type I had a high basal 1,25(OH)2D value, which increased further after hPTH-(1-34) infusions. An almost normal increase in serum 1,25(OH)2D was observed in two patients with hypophosphatemic vitamin-D-resistant rickets, one with Lowe's syndrome and the other with primary Franconi's syndrome. We conclude that these results ae important in obtaining an understanding of calcium and vitamin D metabolism in these disorders and that this PTH stimulation test is a useful method to use in evaluating renal responsiveness in 1,25(OH)2D production to PTH in various calcium disorders.     

Effect of hydrochlorothiazide on calcium metabolism in postoperative hypoparathyroidism

Vitamin D3 administered to patients with postoperative hypoparathyroidism increases calcium absorption from the gut and calcium blood levels but leads to hypercalciuria and may produce renal lithiasis. Thiazides decrease calcium excretion with the urine. Therefore, an effect of combined therapy with hydrochlorothiazide, vitamin D3 and calcium on hypoparathyroidism was investigated. Twenty one women were selected out of 135 patients with postoperative hypoparathyroidism. These women were constantly given vitamin D3 (30,000-225,000 IU daily) and calcium. Normocalcemia, hyperphosphatemia and hypercalciuria were noted before the treatment with hydrochlorothiazide. Therapy normalized hypercalciuria but did not change mean differences in calcemia, phosphatemia, magnesemia, blood alkaline phosphatase and phosphates and magnesium clearance factors. Hypercalcemia and necessity to withdraw hydrochlorothiazide together with change of either doses or preparation of vitamin D3 were noted in three patients, including one patient in whom both hypercalcemia and hypercalciuria with the symptoms of vitamin D3 poisoning were observed. The author suggests that combined therapy with hydrochlorothiazide, vitamin D3 and calcium prevents hypercalciuria but may require changes in vitamin D3 dosage and withdrawal of hydrochlorothiazide in some patients.     

Decreased Calcitriol Requirement During Pregnancy and Lactation With A Window of Increased Requirement Immediately Post Partum

ObjectiveTo describe the changes in calcium and cal- citriol requirements during pregnancy and lactation in a pa- tient with hypoparathyroidism due to autosomal dominant hypocalcemia.MethodsWe summarize the clinical presentation and treatment of the patient and review the pertinent literature.ResultsCalcitriol requirements disappeared during pregnancy in a 34-yearold woman with autosomal dominant hypoparathyroidism secondary to an activating mutation in the calciumsensing receptor gene. Within hours after delivery, her serum calcium concentration dropped to 4.7 mg/dL (albumin, 3.2 g/dL), and she required intravenous calcium and reinstitution of calcitriol. When lactation began a few days later, her calcitriol requirement again disappeared. As has occasionally been described in the literature, this patient with hypoparathyroidism required no calcitriol during late pregnancy and lactation to maintain a normal serum calcium level.ConclusionsTo our knowledge, this is the first reported case documenting a period of time between pregnancy and lactation when calcitriol requirements reappeared, likely due to a parathyroid hormone-related protein “window” between delivery, when placental production of parathyroid hormone-related protein stops, and lactation, when mammary gland production begins. (Endocr Pract. 2010:16:459-462)     

Hypoparathyroidism after surgery on thyroid cancer: is there a delayed chance for recovery after a prolonged period of substitutive therapy?

INTRODUCTION: Transient and persistent hypoparathyroidism (HPT) belong to the well known complications of total thyroidectomy performed because of thyroid carcinoma. The true frequency of persistent hypoparathyroidism is often higher than estimated in the reports published by the specialized centers with low rate of complications. THE AIM OF THE STUDY: Investigation whether the repeated check-up, performed over 2 years post thyroidectomy, reveals some cases of recovery in patients diagnosed with persistent HPT post thyroid cancer surgery. MATERIAL AND METHODS: In total, 115 patients were included into the study, all of them treated with vitamin D derivatives and calcium supplementation. In 17 of them a diagnosis of transient hypoparathyroidism was made on the basis of evaluation performed 6 months after surgery, the remaining 98 were diagnosed with persistent HPT. Parathyroid (PTH) function was reevaluated after withdrawal of active vitamin D derivatives for 10 days and of calcium carbonate for two days during the hospital stay in patients admitted for radioiodine scan, thus after thyroxine withdrawal. The control group consisted of 123 DTC (differentiated thyroid carcinoma) patients without parathyroid dysfunction. On the basis of intact PTH serum level and calcium and phosphorus estimations HPT was unequivocally confirmed in 49 patients (50%). The remaining 49 patients exhibited normal PTH level and in 43 (86%) of them Ca(2+) level was also within normal range, thus delayed, recovery from HPT was stated. RESULTS: Our results indicate that reevaluation of hypoparathyroidism post total thyreoidectomy is necessary, as delayed recover of parathyroid dysfunction is a frequent phenomenon. We also propose criteria of reevaluation of HTP in patients on chronic substitutive therapy.     

Prolonged Vitamin D Intoxication in a Patient with Hypoparathyroidism

Pitfalls in the management of hypoparathyroidism are illustrated by the case of a patient who developed hypervitaminosis D while receiving doses of calciferol and of calcium in amounts commonly recommended for treatment. Either the patient was very slow to obtain maximum vitamin D effect or else her sensitivity to vitamin D increased, because she did not become hypercalcemic until two years after treatment was started. The dose of vitamin D was halved to 50,000 units per day and the dose of calcium was lowered to 0.26 g. daily. She failed to remain under medical supervision for the next four years and presented with hypercalcemia and evidence of renal impairment. After vitamin D was discontinued she remained hypercalcemic for nine months.These findings are discussed in the light of current knowledge concerning the actions of parathyroid hormone and vitamin D. The influence of adrenocortical hormones on calcium metabolism is considered. The need to follow up hypoparathyroid patients closely, and to check the level of calcium in the serum, is emphasized.     

Reversible hypertension caused by calcium overloading in a patient with postoperative hypoparathyroidism

A 37-year-old woman with postoperative hypoparathyroidism had hypertension, and elevated plasma renin activity (PRA) and subsequent hyperaldosteronism during a two-month hypercalcemic period caused by vitamin D and excessive calcium supplements. The hypertension with elevated PRA, however, was resistant to the angiotensin II (AII) analog [Sar1, Ile8] ALL. PRA further increased and plasma aldosterone decreased in response to the [Sar1, Ile8] ALL. When the patient became normocalcemic, normotensive and normoreninemic, calcium gluconate (5 mg calcium/kg/h) was infused for one hour. The calcium infusion reproduced hypercalcemic hypertension mediated by an increase in total peripheral resistance. These observations suggest that the hypertension observed while taking vitamin D and excessive calcium supplements may be caused by a direct effect of calcium on peripheral blood vessels and the renin-angiotensin system may play a negligible role.     

Bone mineral density in hypoparathyroid women on LT4 suppressive therapy. Effect of calcium and 1,25(OH)2 vitamin D3 treatment

Our aim was to study the bone mineral density (BMD) of patients with chronic hypoparathyroidism (hypoPTH) after longterm calcium and vitamin D treatment. Twenty hypoPTH women (mean-/+SD, aged 50-/+15 years, IPTH 4-/+6 pg/ml) and 20 matched euparathyroid women (euPTH) after near total thyroidectomy for thyroid cancer, completed with I-131 ablation and on suppressive therapy with L-Thyroxine (LT(4)), were studied. In addition eight hypoPTH patients who were receiving LT(4) replacement therapy after surgery for compressive goiter were simultaneously studied. The hypoPTH patients were on calcium and 1,25(OH)(2) vitamin D(3) therapy to normalize serum calcium. Bone mineral density (BMD) (DXA, at the lumbar spine [L(2)- L(4), LS], femoral neck [FN] and Ward triangle [WT]), serum and urine calcium, serum phosphorus, TOTALALP and osteocalcin were measured. Patients with hypoPTH showed greater lumbar BMD than euPTH patients on suppressive therapy (Z-score; 1.01-/+1.34 vs. -0.52-/+0.70, p<0.05). Serum osteocalcin levels were higher in hypoPTH patients on suppressive therapy compared to hypoPTH patients on replacement therapy. The LS BMD from hypoPTH patients correlated with calcium supplements (r=0.439; p=0.02), 1,25(OH)(2)D(3) dose (r=0.382; p=0.04) and LT(4) dose (r=0.374; p=0.05). Our data suggest that long-term treatment with calcium and 1,25(OH)(2) vitamin D3 supplements in hypoPTH patients on suppressive LT4 therapy results in increased BMD when compared with patients with normal PTH levels.     

Chemotherapy-Induced Hypocalcemia

ObjectiveTo present a unique case of transient, asymptomatic chemotherapy-induced hypocalcemia not attributable to hypomagnesemia or tumor lysis syndrome and review causes of hypocalcemia related to cancer with and without use of chemotherapy.MethodsWe present a case detailing the clinical and laboratory findings of a patient who had severe hypocalcemia during chemotherapy and discuss causes of hypocalcemia with an extensive literature review of chemotherapeutic agents associated with this biochemical abnormality.ResultsIn a 90-year-old man, hypocalcemia developed during 2 courses of chemotherapy for Hodgkin lymphoma, with partial recovery between courses and normal serum calcium 10 months after completion of treatment. Magnesium, vitamin D, and parathyroid hormone levels were low normal. There was no evidence of tumor lysis syndrome. Of the various agents administered, vinca alkaloids seemed the most likely cause. Serial testing suggested that the underlying mechanism may have been acquired, reversible hypoparathyroidism. No other similar case was found in the published literature.ConclusionThe severe hypocalcemia in our patient could not be attributed to hypomagnesemia or tumor lysis syndrome, and it was clearly associated with the timing of his chemotherapeutic regimen. Possibilities include direct parathyroid hormone suppression or alteration of calcium sensing by the chemotherapeutic drugs. Serum calcium surveillance before and during chemotherapeutic management of cancer patients may reveal more instances and provide insight into the exact mechanism of this lesser known yet striking complication. (Endocr Pract. 2010;16:284-290)     

Efficacy and safety of long term treatment of unresponsive hypoparathyroidism using multipulse subcutaneous infusion of teriparatide

Vitamin D nonresponsive hypoparathyroidism is uncommonly seen in the clinical practice. The use of new treatment modalities, including teriparatide administration, provides an alternative requiring its validation. We report the first case of hypoparathyroidism refractory to vitamin D that was successfully controlled for 5 years by teriparatide treatment. A 53-year-old woman presented severe hypoparathyroidism after thyroidectomy. No therapeutic response was obtained with oral and i. v. calcium and magnesium, or even with 5 μg calcitriol/day. Digestive disorders were ruled out and heterologous parathyroid transplant was ineffective. Subcutaneous (s. c.) recombinant human PTH 1-34 (rhPTH-teriparatide) plus oral calcitriol, calcium, and magnesium, were partially effective, but effectiveness of 20 μg teriparatide lasted less than 4 h and stable calcemia was not possible even with 4-6 injections/day. Multipulse s. c. pump driven infusion of teriparatide achieved complete normalization of serum calcium, phosphate, magnesium, calciuria, and magnesuria with relatively low teriparatide doses (25-35 μg/day) after the first day of treatment. Effectiveness of this treatment modality was maintained for 5 years. The only significant side effect observed during these years was the development of subcutaneous nodules with occasional insufficient control of calcemia. A gain in bone mineral density was observed after the first year of treatment, which had remained stable and within normal values, thereafter until now. No abnormalities in bone scintigraphy were detected in the follow-up. Vitamin D unresponsive hypoparathyroidism maybe safely and effectively controlled at long term by s. c. multipulse pump treatment recombinant human PTH.     

Renal handling of calcium in hypoparathyroidism.

Treatment of hypoparathyroidism usually requires the use of pharmacological doses of parent vitamin D or near physiological amounts of the hydroxylated metabolites, calcitriol or alphacalcidol. Vitamin D intoxication and hypercalcaemia may be a problem but can be minimised by the use of small doses of vitamin D or its metabolites combined with large amounts of oral calcium. The response to treatment can be easily monitored by measuring serum and urinary calcium and creatinine concentrations. This allows the derivation of two simple indices reflecting calcium load presented to the kidney (calcium excretion in mmol/l glomerular filtrate) and renal tubular calcium reabsorption (TmCa/GFR). These can be used to predict the requirement of calcium supplements and also identify those patients at particular risk of hypercalcaemia.     

Safety of treatment for subclinical osteomalacia in the elderly.

Forty one elderly patients admitted to hospital for acute illnesses were also found to have subclinical osteomalacia. Immediately before discharge, therefore, all were randomised to receive either vitamin D2 25 micrograms daily, alfacalcidol 0.5 micrograms daily, or placebo. Treatment was given for at least three months, those allocated to placebo then being switched to an active drug. Within the first three months of treatment with either of the active drugs most patients had exhibited a fall to normal in osteoid values. In only four treatment periods was there a mild increase in serum calcium concentration, and in no patient was this accompanied by deterioration in renal function. Any increase in serum creatinine concentration was invariably attributable to the underlying disease for which the patient had been admitted in the first place. Subclinical osteomalacia in the elderly may be corrected by relatively low doses of alfacalcidol (0.5 micrograms daily) or vitamin D2 (25 micrograms daily) given for three months. Such treatment is safe and not accompanied by a serious risk of hypercalcaemia or renal impairment.     

Evaluation of the parathyroid function in six patients with hypophosphatemic osteomalacia,including a case of tertiary hyperparathyroidism developing during combined oral phosphate and vitamin D therapy

AIM: To describe a case of tertiary hyperparathyroidism after long-term phosphate and vitamin D therapy and the retrospective evaluation of parathyroid function in 6 patients with hypophosphatemic osteomalaica. METHODS: We evaluated the parathyroid function by measuring iPTH before and during treatment and divided the patients into normal and elevated serum iPTH groups. RESULTS: In the normal serum iPTH group, the 4 patients were all males, whereas the 2 patients in the elevated serum iPTH group were females. Clinical characteristics and biochemical results showed no differences between the two groups. One of the women with an elevated iPTH level (224 pg/ml) had a normal serum calcium level and no evidence of increasing parathyroid uptake by (99m)Tc-MIBI scan 52 months after treatment. The other woman also had an elevated iPTH level (483 pg/ml) and a normal serum calcium level 56 months after treatment. However, in this latter case both her iPTH (1,447 pg/ml) and serum calcium (11.3 mg/dl) levels were elevated 113 months after treatment, when a (99m)Tc-MIBI scan showed increased uptake in all four parathyroid glands during early and delayed phases of the scan. Parathyroidectomy was performed after the diagnosis of tertiary hyperparathyroidism was made, and the histological findings showed adenomatous hyperplasia. CONCLUSIONS: Our findings indicate that even with vitamin D therapy, long-term phosphate therapy may lead to the development of secondary or tertiary hyperparathyroidism in hypophosphatemic osteomalacia and, therefore, suggest that it is important to carefully monitor the parathyroid function during therapy in those with hypophosphatemic osteomalacia.     

Maternal Factors in Neonatal Hypocalcaemia: A Study in Three Ethnic Groups

To assess the significance of various maternal and neonatal factors in the aetiology of neonatal tetany we have investigated the serum calcium, phosphorus, magnesium, and heat-labile alkaline phosphatase of 250 mothers from three ethnic groups at several stages of pregnancy and the serum calcium, phosphorus, and magnesium of many of their infants. Subclinical hypocalcaemia was found to be much commoner in full-term infants on the sixth day of life than is generally appreciated, especially during the winter months and in babies of Asian parents. It is considered that this is a result of high phosphorus loads in artificial milks and is also influenced by maternal vitamin D and possibly calcium intake during pregnancy. The importance of ensuring that Asian women take adequate vitamin D supplements during pregnancy is stressed.     

Effects of vitamin K2 administration on calcium balance and bone mass in young rats fed normal or low calcium diet

OBJECTIVE: The purpose of this study was to examine the effects of vitamin K2 administration on calcium balance and bone mass in young rats fed a normal or low calcium diet. METHODS: Forty female Sprague-Dawley rats, 6 weeks of age, were randomized by stratified weight method into four groups with 10 rats in each group: 0.5% (normal) calcium diet, 0.1% (low) calcium diet, 0.5% calcium diet + vitamin K2 (menatetrenone, 30 mg/100 g chow diet), and 0.1% calcium diet + vitamin K2. After 10 weeks of feeding, serum calcium and calciotropic hormone levels were measured, and intestinal calcium absorption and renal calcium reabsorption were evaluated. Bone histomorphometric analyses were performed on cortical bone of the tibial shaft and cancellous bone of the proximal tibia. RESULTS: Feeding a low calcium diet induced hypocalcemia, increased serum parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D [1,25(OH)2D] levels with decreased serum 25-hydrovyvitamin D [25(OH)D] level, stimulated intestinal calcium absorption and renal calcium reabsorption, and reduced cortical bone mass as a result of decreased periosteal bone gain and enlarged marrow cavity, but did not significantly influence cancellous bone mass. Vitamin K2 administration in rats fed a low calcium diet stimulated renal calcium reabsorption, retarded the abnormal elevation of serum PTH level, increased cancellous bone mass, and retarded cortical bone loss, while vitamin K2 administration in rats fed a normal calcium diet stimulated intestinal calcium absorption by increasing serum 1,25(OH)2D level, and increased cortical bone mass. CONCLUSION: This study clearly shows the differential response of calcium balance and bone mass to vitamin K2 administration in rats fed a normal or low calcium diet.     

Celiac Disease Manifesting as Isolated Hypocalcemia

ObjectiveTo describe a patient who presented with hypocalcemia and hypocalciuria as the initial manifestations of celiac disease, despite a normal vitamin D status.MethodsWe review the diagnostic evaluation, treatment, and biochemical and bone mineral density responses of a patient with asymptomatic celiac disease, which was initially suggested because of a low serum calcium level that became attributable to isolated malabsorption of calcium.ResultsA 36-year-old woman presented with hypocalcemia in the presence of normal serum 25- hydroxyvitamin D and high serum 1,25-dihydroxyvitamin D levels. She had hypocalciuria and secondary hyperparathyroidism that were refractory to pharmacologic calcium and cholecalciferol supplementation. Fecal calcium excretion indicated malabsorption of calcium, and biopsy of the small intestine demonstrated pathologic changes characteristic of celiac disease. Bone mineral density, determined by dual-energy x-ray absorptiometry, was in the osteopenic range at the femoral neck. The initiation of a gluten-free diet resulted in correction of all biochemical abnormalities and a substantial increase in bone mineral density.ConclusionPrimary intestinal malabsorption of calcium without concomitant vitamin D deficiency is possible in celiac disease because of the preferential involvement of the proximal small intestine early in the disease process. Our patient had hypocalcemia caused by celiac disease and values for serum 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D that were normal and elevated, respectively. Correction was demonstrated after dietary gluten withdrawal. (Endocr Pract. 2004;10:203-207)     

An acromegalic patient with recurrent urolithiasis

A 52-year-old man with an acromegalic appearance of prolonged duration suffered abdominal colic attacks and hematuria during the middle of the course of the disease. The patient was diagnosed as having urolithiasis caused by increased urinary calcium. The calcium metabolic disorder was not considered to be due to hyperparathyroidism because serum calcium and PTH levels were within the normal range and no abnormality was observed in a parathyroidal scintigraph. The serum 1,25-dihydroxyvitamin D (1,25-(OH)2D) levels (55.0 and 73.0 pg/ml) were higher than the normal range (27.2-53.8 pg/ml). A selective adenomectomy by the transsphenoidal route (Hardy's method) was performed, resulting in an improvement in the hypercalciuria and urolithiasis, and a decrease in the levels of serum 1,25-(OH)2D (23.0 and 23.0 pg/ml). These findings suggest that GH may promote the activation of vitamin D in the kidney in acromegaly, resulting in an acceleration of calcium absorption in the intestine through the action of activated vitamin D and the induction of increased urinary calcium excretion by the urinary excretion of excessive blood calcium.     

Vitamin D Intoxication Treated with Porcine Calcitonin

Porcine calcitonin was used to treat three patients with hypercalcaemia due to vitamin D intoxication. In two patients a rapid and sustained fall to normal in serum calcium occurred within three days, in the third patient normocalcaemia was achieved in seven days. In view of its rapid and sustained effect calcitonin may be of value in the urgent treatment of hypercalcaemia due to vitamin D intoxication.     

The influence of bariatric surgery on calcium homeostasis and biochemical markers of bone turnover in patients with morbid obesity

INTRODUCTION: Obese patients may have abnormal calcium homeostasis because of unbalanced diet and decreased sun exposure. Bariatric surgery itself may lead to disturbances in calcium homeostasis (and in consequence changes in bone mass) or increase preexisting metabolic derangements. The aim of the study was: 1. To assess calcium homeostasis and biochemical markers of bone turnover in patients with morbid obesity. 2. To determine the impact of bariatric surgery on parameters mentioned above. 3. To establish recommendations for supplementation with calcium and vitamin D in morbidly obese patients after bariatric surgery. MATERIAL AND METHODS: Serum calcium, parathormone (PTH), vitamin D (25(OH)D), biochemical markers of bone turnover (beta-CrossLaps as a marker of bone resorption and osteocalcin as a marker of bone formation) and urine calcium as well as fat mass, lean mass and bone mineral content (by DXA) were measured before bariatric surgery of the stomach (VBG or GBP) in 57 morbidly obese patients (48 women, 9 men; mean age 35.9 y). The same procedures were repeated six months after operation in 28 of them (24 women, 4 men). Daily calcium intake was also determined based on food questionnaire. RESULTS: Biochemical findings in the group of patients before bariatric surgery were as follows: serum calcium, beta-CrossLaps and urine calcium were within normal range, PTH concentration was increased to 81.0 pg/ml and 25(OH)D as well as osteocalcin concentration decreased (4.9 ng/ml and 13.6 ng/ml, respectively). Six months after bariatric surgery there was no change in serum and urine calcium, PTH concentration decreased to normal level (46.8 pg/ml), 25(OH)D concentration increased to 6.5 ng/ml (not significant) and still remained below normal range. Markers of bone turnover--both resorption and formation--increased (beta-CrossLaps over normal range to 0.594 ng/ml, osteocalcin to normal range 26.8 ng/ml). Daily calcium intake was below RDA before and after bariatric procedure. CONCLUSIONS: 1. Patients with morbid obesity have secondary hyperparathyroidism and deficiency of vitamin D. 2. Abrupt weight loss after bariatric surgery is accompanied by the regression of secondary hyperparathyroidism, decrease of the deficiency of vitamin D and increase in bone turnover. 3. Supplementation with vitamin D and calcium is recommended for patients with morbid obesity after bariatric surgery.     

Serum intact parathyroid hormone concentration measured by a two-site immunoradiometric assay in normal subjects and patients with various parathyroid disorders.

Serum intact parathyroid hormone (PTH) concentration was measured by a two-site immunoradiometric assay (IRMA) in normal subjects and patients with various parathyroid disorders. Serum intact PTH levels were all within the detection limit of the IRMA in normal subjects, and there was a significant negative correlation between serum calcium (Ca) and intact PTH levels. Although 3 out of 26 patients (11.5%) with primary hyperparathyroidism had a normal serum intact PTH concentration, these patients could be readily discriminated from normal subjects by plotting serum intact PTH against the serum Ca concentration. In contrast, serum intact PTH was undetectable in 16 out of 17 patients (94.1%) with idiopathic hypoparathyroidism. Patients with pseudohypoparathyroidism (PHP) type I, mostly under treatment with active vitamin D, exhibited wide distribution of serum intact PTH concentration, and appeared to belong to two distinct subgroups. One group of patients demonstrated a similar relationship between serum intact PTH and Ca levels to normal subjects. The other exhibited much higher serum intact PTH levels despite a normal serum Ca concentration, and no obvious relationship could be observed between the two parameters. These results demonstrate that an inverse relationship between serum Ca and intact PTH can be demonstrated in normal subjects with normocalcemia, that most of the parathyroid disorders can be diagnosed by measuring serum Ca and the intact PTH concentrations simultaneously, and that patients with PHP can be divided into two subgroups: one with a normal relationship between serum Ca and intact PTH, and the other with a high serum PTH level in the face of normocalcemia.     

A Case of Calciphylaxis in a Patient with Hypoparathyroidism and Normal Renal Function

ObjectiveTo present the case of a patient with a history of thyroid cancer, postsurgical hypoparathyroidism, chronic calcitriol use, and normal renal function who presented with painful skin lesions secondary to calciphylaxis.MethodsWe describe the history, biochemistry, histopathology, evaluation, and management of this patient.ResultsA 47-year-old female with hypoparathyroidism, chronically treated with calcitriol and calcium, presented with exquisitely painful skin ulcerations. Four months prior to the onset of symptoms, she had initiated warfarin therapy for atrial fibrillation. Review of laboratory data from the past year revealed elevated calcium and phosphorus levels. A diagnosis of calciphylaxis was made based upon pathologic evaluation of a skin biopsy. Management included titration of calcitriol and calcium to maintain serum calcium and phosphate levels in the low-normal range. Sodium thiosulfate was administered at a dose of 25 mg intravenously 3 times a week with some resolution in the patient’s pain. Unfortunately, the patient battled recurrent bacteremia and sepsis, presumably related to her calciphylaxis wounds, and ultimately succumbed to complications from sepsis.ConclusionAlthough calciphylaxis is typically associated with renal insufficiency and secondary hyperparathyroidism, we highlight the case of a patient with normal renal function and hypoparathyroidism. Patients treated with chronic calcitriol should have serum calcium and phosphorus monitored closely and may benefit from non– calcium-based phosphate binders if hyperphosphatemia becomes unavoidable. This is especially important in the presence of other risk factors for calciphylaxis, including warfarin use. (Endocr Pract. 2014;20:e102-e105)