Serum parathyroid hormone concentration measured by highly sensitive assay in post-thyroidectomy hypocalcemia of patients with Graves' disease

To investigate the role of parathyroid function in transient hypocalcemia after subtotal thyroidectomy for Graves' disease, the serum parathyroid hormone (PTH) concentration and nephrogenous (N) cAMP were measured in 16 patients before and after surgery. Serum PTH was measured with two commercially available kits (PTH-M, PTH-C), PTH-M is a recently developed highly sensitive assay using an antibody recognizing the mid-portion of human PTH and a synthetic 125I-tyr45-human PTH (43-68) as a radioligand. One of the 16 patients had severe clinical tetany and had a markedly lower PTH-M concentration and NcAMP after thyroidectomy. However, no significant change in serum PTH-M, PTH-C and NcAMP were observed in the other patients, although their serum calcium (Ca) concentrations decreased significantly. The Data were analyzed by dividing the patients according to the change in serum Ca or PTH. Serum PTH-M and PTH-C significantly decreased in 4 patients whose serum Ca clearly decreased after surgery. Serum Ca on the first postoperative day was significantly lower in patients whose serum PTH decreased after thyroidectomy than in patients whose serum PTH did not. Furthermore, the serum Ca concentration was significantly correlated with PTH-M, and with NcAMP on the third postoperative day. These data proved that hypofunction of the parathyroid gland is important in transient hypocalcemia after subtotal thyroidectomy for Graves' disease. The pathogenetic mechanism of transient hypocalcemia was discussed in comparison with the data from a patient who had overt parathyroid injury.     

Safety of Immediate Discharge after Parathyroidectomy: A Prospective Study of 3,000 Consecutive Patients

ObjectiveTo evaluate the safety of immediate discharge after parathyroidectomy and to establish a protocol for the amount and duration of supplemental orally administered calcium for patients with varied clinical presentations of primary hyperparathyroidism.MethodsA 40-months, prospective, single institution, cohort study of 3,000 consecutive patients undergoing parathyroidectomy and discharged within 2.5 hours after the operation is reviewed. The amount of oral calcium supplementation prescribed postoperatively varied according to a protocol that considered the degree of serum calcium elevation preoperatively as well as the intraoperative findings (hyperplasia versus adenoma). Symptoms of hypocalcemia were tracked, and all surgical outcomes were monitored.ResultsWith use of the reported protocol, less than 7% of patients had postoperative symptoms of hypocalcemia, most of whom were successfully selftreated with additional orally administered calcium. Only 6 patients (0.2%) required a visit to the emergency department for intravenous calcium infusion, all occurring on postoperative day 3 or later, and none of these patients required rehospitalization. Postoperative calcium requirements varied on the basis of the degree of serum calcium elevation preoperatively, number of parathyroid glands removed or subjected to biopsy, presence of morbid obesity, and presence of severe osteoporosis.ConclusionPatients with primary hyperparathyroidism can be sent home immediately after successful parathyroidectomy, provided specific measures are taken regarding postoperative oral calcium supplementation. Use of a specific calcium dosing protocol that considers several patient variables will prevent the postoperative development of symptomatic hypocalcemia in 93% of patients, identify patients at high risk of hypocalcemia, and allow most patients who develop symptoms of hypocalcemia to self-medicate in a simple and predictable fashion. Routine monitoring of postoperative serum calcium levels in the hospital can be safely eliminated if the details of this protocol are followed. (Endocr Pract. 2007;13:105-113)     

Postoperative hypoparathyroidism: long term observation and therapy]

Hundred thirty patients with surgical hypoparathyroidism were followed up. Group I involved 45 patients with mild and group II--85 patients with severe surgical hypoparathyroidism. A delay in vitamin D3 therapy was X +/- SD = 4.2 +/- 8.1 years. A delay in introducing vitamin D3 therapy correlated with the duration of hypoparathyroidism (r = 0.93; 8.9 +/- 9.6 years). Follow up period lasted for 15 years and was 4.3 +/- 3.8 years out of which the attempts to establish ultimate and effective dose of vitamin D3 lasted 1.8 +/- 2.4 years. Dose of vitamin D3 was adjusted 5 times, on the average. Effective daily dose was 4,200-22,500 IU (9,311 +/- 7,252) in group I, and 30,000-195,000 IU (51,385 +/- 32,978) in group II whereas maximum daily dose was 75,000 and 250,000 IU respectively (p < 0.001). Some patients were given 25-OH-D3 in daily doses of 50-225 micrograms or 25(OH)2-D3 in daily dose of 0.10-0.75 micrograms. Calcium oral doses of 400-1600 mg daily were administered to 115 patients. In case of high hypercalciuria (over 350 mg/24 h) hydrochlorothiazide (43 +/- 17 mg a day) or chlorthalidone (60 +/- 22 mg a day) normalized calciuria. Low phosphate diet and aluminium oxide (4.4 +/- 1.7 g a day) were more frequently used in group II. Period of time necessary to establish an effective dose of vitamin D3 is long in patients with surgical hypoparathyroidism. Several dose adjustments are required. Maximum daily vitamin D3 dose required for normocalcemia is approximately higher by 1/3 in the early period of the treatment than the effective maintenance dose. A decrease in diet phosphate content, inhibition of phosphates absorption in the gut or blocking increased calcium loss with the urine are necessary in some patients, only.     

The Optimal Parathyroid Hormone Cut-Off Threshold for Early and Safe Management of Hypocalcemia After Total Thyroidectomy

ObjectiveTo define optimal intact parathyroid hormone (iPTH) cut-off threshold predictive of hypocalcemia after total thyroidectomy for safe and effective postoperative management.MethodsThis prospective single center study was done in 2 phases. In phase I, predictors of symptomatic hypocalcemia were analyzed and the receiver operating characteristic curve was used to define the optimal iPTH cut-off threshold predictive of hypocalcemia. Phase II studied giving prompt prophylactic supplemental calcium and vitamin D to all patients who had iPTH levels below the calculated threshold, while phase I patients were given prompt selective supplementation if they had postoperative hypocalcemia or symptoms.ResultsUnivariate analysis of patients in phase I showed that postoperative iPTH was the only significant variable that can predict symptomatic hypocalcemia. Using receiver operating characteristic curve and Youden index, the confirmed optimal cut-off threshold predictive of hypocalcemia was iPTH 19.95 pg/mL, with area under the curve of 0.903, 100% sensitivity, negative predictive value, and highest Youden index, while iPTH 15 pg/mL and iPTH 10 pg/mL were less optimal. Symptomatic hypocalcemia occurred in 30% of the phase I cohort who received selective supplementation versus 3% of those in the phase II cohort who received prophylactic supplementation. Return to emergency department and need for intravenous calcium were also significantly better in phase II.ConclusioniPTH cut-off for post-thyroidectomy hypocalcemia was 19.95 pg/mL. Low-risk patients were discharged with no supplementation while all high-risk patients received prompt calcium and vitamin D supplementation, which led to effective hypocalcemia management and safe 24-hour discharge.     

Effect of 1alphaOH-vitamin D3 in a case of pseudohypoparathyroidism.

A 37-year-old woman with typical features of pseudohypoparathyroidism (chronic tetany, paresthesia, persistent hypocalcemia, round face, short stature, short metacarpals and metatarsals, cucutaneous calcification and lack of response to exogenous and endogenous parathyroid hormone as regards urinary phosphate and cyclic AMP excretion) was treated with oral administration of 2 microgram/day of 1alphaOH-vitamin D3. Serum calcium started to rise within 3 days returning to the normal level with disappearance of symptoms referrable to hypocalcemia. Such a favorable effect of a small dose of 1alphaOH-vitamin D3 in a patient with typical hypoparathyroidism suggests an important role of disturbance of 1alpha-hydroxylation of vitamin D3 by the kidney in the pathogenesis of calcium and phosphorus abnormality in this disease. Forty-four cases of pseudohypoparathyroidism in the Japanese literature were briefly reviewed.     

Postoperative hypoparathyroidism: risk of complications]

For assessing the risk of adverse complications of surgery the group of 130 patients with post-operational hypoparathyroidism was analysed. Surgical hypoparathyroidism has been diagnosed in 51% of operated on thyroid gland patients. Laryngeal nerves have been damaged in 46.6% of patients. The injury to laryngeal nerves has been irreversible in 2/3 of patients, and reversible in the remaining 1/3. Cataract, nephrolithiasis and vitamin D3 intoxication have been observed in some cases before surgery. Their incidence increased in severe surgical hypoparathyroidism. Osteoporosis of the spine has been diagnosed in 49% of patients including some with vertebral fractures. No correlation between the degree of spine osteoporosis and diagnosis before surgery, number of operations on thyroid gland, and type of therapy has been noted. The symptoms of hypercalcemia have been diagnosed in 5 patients out of which hypercalcemia has been transient in 2 patients, and lasted for 1-5 months in the remaining 3 patients. The results of 7,873 analyses of mineral metabolism have been assessed. Hypocalcemia has been found in 38.4%, hypercalcemia in 1.6%, hypomagnesemia in 25.7%, hyperphosphatemia in 41.5%, decreased alkaline phosphatase serum activity in 28.7%, and hypercalciuria in 22.4% of cases. Surgical hypoparathyroidism is frequently accompanied by surgical hypothyroidism and injury to the recurrent laryngeal nerves.     

Changes in the ultrastructure of synapses and neurons of the ventral horns of the spinal cord in cats with tetany as a result of the removal of the parathyroid glands

An electron microscopic investigation on ultrastructure of synapses and ventral horns of the lumbar thickening in the spinal cord of cats with parathyroprival tetany has been performed. When motor disorders are clearly seen on the 2d - 4th days after removal of the parathyroid glands, together with the changes demonstrating functional activity of the synapses, certain irreversible degenerative changes of the "dark" type are seen in the axodendritic and axosomatic synapses. A complex of structural-metabolic changes has been revealed in the motor neurons, they have both functional-compensatory and degenerative character. It is possible to suggest that the changes revealed at parathyroprival tetany result from a disturbed metabolism and increased afferent influences.     

Incidence,Risk Factors,and Clinical Implications of Delayed Hypoparathyroidism on Postoperative Day two Following Total Thyroidectomy for Papillary Thyroid Carcinoma

Objective: This study aimed to investigate the incidence rates, risk factors, and clinical implications of delayed hypoparathyroidism on postoperative day 2 (POD-2) after total thyroidectomy in patients with papillary thyroid carcinoma.Methods: This study included 410 patients with normal serum intact parathyroid hormone (iPTH) and calcium levels on postoperative day 1 (POD-1) who were classified into 2 groups according to the presence or absence of delayed hypoparathyroidism on POD-2.Results: Of the 410 patients, 98 experienced delayed hypoparathyroidism on POD-2 (23.9%). The significant risk factors for delayed hypoparathyroidism on POD-2 included female gender, age older than 45 years, central lymph node dissection, increased number of excised lymph nodes, and low POD-1 versus preoperative iPTH ratios. Additionally, delayed hypoparathyroidism on POD-2 was found to be a significant risk factor for hypocalcemia on POD-2 and permanent hypoparathyroidism.Conclusion: Prophylactic calcium supplementation and long-term surveillance for permanent hypoparathyroidism should be considered in patients with risk factors for delayed hypoparathyroidism on POD-2.Abbreviations: CI = confidence interval; iPTH = intact parathyroid hormone; OR = odds ratio; POD-1 = postoperative day 1; POD-2 = postoperative day 2; PTC = papillary thyroid carcinoma; ROC = receiver operating characteristic     

Ultrasound-Guided Radiofrequency Ablation for the Treatment of Primary Hyperparathyroidism: An Efficacy and Safety Study

ObjectiveTo evaluate the efficacy and safety of radiofrequency ablation (RFA) for the treatment of primary hyperparathyroidism (pHPT).MethodsOur study enrolled 25 patients who were treated with RFA for pHPT from September 2015 to January 2020. The serum intact parathyroid hormone (iPTH), calcium, and phosphate levels were tested within 1 week before RFA and at 1 day, 1 month, 3 months, 6 months, and 12 months after ablation. The ablation areas were evaluated using ultrasound at 1, 3, 6, and 12 months after RFA. Postoperative complications, including voice hoarseness, hematoma, postoperative pain, incision infections, hypoparathyroidism, and hypocalcemia, were recorded.ResultsA total of 25 patients with pHPT (mean age, 53.9 ± 10.9 years; 22 women and 3 men) with 29 enlarged parathyroid glands were treated with RFA. Of the 25 patients, 22 were treated in 1 session and 3 were treated in 2 sessions. Serum iPTH and calcium levels decreased significantly on day 1 after RFA (all P < .05). A total of 21 patients had normal levels of serum iPTH and calcium after RFA, with a cure rate of 84%. At the 12-month follow-up, 26 treated parathyroid glands exhibited a volume reduction rate of >70%. There were only a few minor complications, including 4 cases of postoperative pain (in 4 of the 25 patients [16%]) and 1 case of mild postoperative transient hypocalcemia (in 1 of the 25 patients [4%]).ConclusionUltrasound-guided RFA is an effective and safe technique for the treatment of carefully selected patients with pHPT. However, larger sample size and longer follow-up are still needed to further confirm its clinical value.     

Surgical treatment of secondary hyperparathyroidism in patients with chronic renal failure: reevaluation of indications for parathyroidectomy

On reviewing the preoperative clinical and laboratory findings and the surgical response seen in our series of 32 patients with renal hyperparathyroidism, the indication for parathyroidectomy was reevaluated. During the 5-year period from 1975 to 1979, parathyroid resection was performed in 9 patients who had various conditions for which surgery had been thought indicated. During the following period from January 1980 to March 1985, parathyroidectomy was carried out on 23 patients all of whom had roentgenologic evidence of generalized fibrous osteitis except for two whose indication for surgery was an elevation of the serum alkaline phosphatase level more than 45 KA units. The resected parathyroid glands had increased to 1 g or more in total weight in all the 25 patients who showed distinct postoperative improvement. Laboratory evidence indicating the presence of generalized fibrous osteitis, such as subperiosteal resorption on phalanx roentgenograms and high serum alkaline phosphatase level, along with marked elevation of the plasma immunoreactive parathyroid hormone level, proved to be a good indicator for medically uncontrollable secondary hyperparathyroidism. Fracture, heterotopic calcification, pruritus or persistent hypercalcemia was not a parameter of severe hyperparathyroidism warranting parathyroid resection, unless there was concomitant evidence of fibrous osteitis. The preoperative use of the recently developed noninvasive techniques for parathyroid localization also proved to be useful in detecting the parathyroid glands large enough to fulfill the requirements for parathyroidectomy.     

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)     

Development of an imaging device for label-free parathyroid gland identification and vascularity assessment

During thyroid surgeries, it is important for surgeons to accurately identify healthy parathyroid glands and assess their vascularity to preserve their function postoperatively, thus preventing hypoparathyroidism and hypocalcemia. Near infrared autofluorescence detection enables parathyroid identification, while laser speckle contrast imaging allows assessment of parathyroid vascularity. Here, we present an imaging system combining the two techniques to perform both functions, simultaneously and label-free. An algorithm to automate the segmentation of a parathyroid gland in the fluorescence image to determine its average speckle contrast is also presented, reducing a barrier to clinical translation. Results from imaging ex vivo tissue samples show that the algorithm is equivalent to manual segmentation. Intraoperative images from representative procedures are presented showing successful implementation of the device to identify and assess vascularity of healthy and diseased parathyroid glands.     

Recombinant Human Parathyroid Hormone Therapy (1-34) In an Adult Patient with a Gain-of-Function Mutation in the Calcium-Sensing Receptor-a Case Report

ObjectiveTo describe a case of hypocalcemia in a patient with a gain-of-function mutation in the calcium-sensing receptor that was undetected until adulthood and successfully treated with recombinant parathyroid hormone.MethodsThe clinical findings, laboratory data, and a review of the pertinent literature are presented.ResultsA 55-year-old woman was hospitalized and seen by the endocrinology consult service for hypocalcemia that was refractory to repeated doses of intravenous calcium gluconate. She expressed concern about chronic leg muscle cramps and paresthesias of the lips and fingertips. In addition, she had no history of neck surgery, neck irradiation, or any autoimmune disease. She was a well-appearing female with no dysmorphic features or skin changes. Laboratory tests revealed hypocalcemia, hyperphosphatemia, hypomagnesemia, and hypovitamino-sis D. Her parathyroid hormone concentration (PTH) was low at 14.2 pg/mL. Her PTH and calcium concentrations remained low despite repletion of magnesium and treatment with calcitriol and oral calcium replacement. A 24-hour collection for urinary calcium showed inappropriate hypercalciuria. Medical records showed her hypocalcemia to be chronic. Additionally, several family members had also complained of muscle cramps. A congenital cause of her hypoparathyroidism was considered, and genetic testing confirmed heterozygosity for a gain-of-function mutation in the calcium-sensing receptor gene associated with autosomal dominant familial isolated hypoparathyroidism (ADH). Treatment with subcutaneous recombinant human parathyroid hormone teriparatide (rhPTH [1-34]) 20 mcg twice daily for three days normalized her calcium and phosphorus concentrations.ConclusionrhPTH (1-34) is an effective treatment for patients with hypoparathyroidism due to gain-of-function mutations in the calcium-sensing receptor. ADH can be insidious in presentation and the diagnosis can be missed unless there is a high index of suspicion. (Endocr Pract. 2013;19:e24-e28)     

Parathyroid gland dysfunction in 22q11.2 deletion syndrome

BACKGROUND: 22q11 deletion syndrome (22q11DS) is characterized by conotruncal cardiac defects and hypoplasia of parathyroid glands and thymus, which result in variable hypoparathyroidism (HPT) and immune deficiency. METHODS: To study the course of HPT and the spectrum of other associated manifestations we evaluated all patients with 22q11DS, confirmed by fluorescence in situ hybridization, and HPT who were under follow-up at the Calcium-bone clinic, The Hospital for Sick Children, Toronto. Patients were clinically assessed and their hospital records were reviewed. RESULTS: Eighteen patients were included. At follow-up assessment at median age of 7.3 years HPT was judged complete in 11 (61%) and partial in 7 patients (39%). Patients with complete HPT presented with hypocalcemia later (median age at diagnosis 2.4 vs. 0.0 years) and more often with a hypocalcemic seizure than patients with partial HPT (73 vs. 29%). The spectrum of other associated manifestations did not differ between the groups. CONCLUSIONS: HPT in patients with 22q11DS is often partial. Many of the patients present with a hypocalcemic seizure which is predictive of complete HPT. Patients with complete and partial HPT do not differ in respect to their other associated features. Patients with features of 22q11DS should be actively screened for hypocalcemia to prevent development of symptomatic hypocalcemia.     

Hypocalcemic cardiomyopathy due to untreated hypoparathyroidism

Hypocalcemic cardiomyopathy due to hypoparathyroidism is a very rare condition which is usually refractory to conventional treatment for cardiac failure but which responds favorably to restoration of normocalcemia. A 55-year-old man and a 46-year-old woman with a history of postoperative hypoparathyroidism presented with symptoms of cardiac failure and hypocalcemia. A presumptive diagnosis of dilated cardiomyopathy was considered by echocardiography and endomyocardial biopsies were consistent with cardiomyopathy. The coronary angiograms were normal and there was no apparent cause for dilated cardiomyopathy in these patients. The history of the patients and partial recovery of cardiac function after restoration of normocalcemia suggest that hypocalcemia was the cause of dilated cardiomyopathy.     

Idiopathic Hypoparathyroidism Presenting with Severe Hypocalcemia and Asymptomatic Basal Ganglia Calcification Followed by acute Intracerebral Bleed

ObjectiveTo report a case of idiopathic hypoparathyroidism presenting with severe hypocalcemia and intracerebral calcifications that resulted in a spontaneous intracerebral bleed.MethodsWe present the clinical, laboratory, and radiologic findings in a woman with idiopathic hypoparathyroidism who developed spontaneous intracerebral bleed in the setting of chronic intracerebral calcifications.ResultsA 37-year-old woman presented with vague symptoms of hypocalcemia. Clinical evaluation revealed brisk deep tendon Reflexes and positive Chvostek’s and Trousseau’s signs. The serum calcium level was 3.7 mg/ dL (reference range, 8.0 to 10.6 mg/dL) and the phosphorus level was 8.2 mg/dL (reference range, 2.3 to 5.0 mg/dL). Serum intact parathyroid hormone was undetectable. Computed tomography of the head showed extensive bilateral symmetrical calcification of basal ganglia and dentate nucleus in the cerebellum and centrum semiovale. Fluid and electrolytes were replaced appropriately, and calcium and calcitriol were prescribed. While in the hospital, the patient developed an acute intracerebral bleed confirmed by computed tomography. The patient recovered without neurologic sequelae and was discharged from the hospital on calcium supplementation and calcitriol. Repeated computed tomography of the head 3 years later demonstrated complete resolution of the bleed.ConclusionThis case suggests that patients with severe hypoparathyroidism and intracerebral calcification may be at risk for spontaneous intracerebral bleed and should be monitored accordingly. (Endocr Pract. 2007; 13:487-492     

Hyperparathyroid Crisis Due to Asymmetric Parathyroid Hyperplasia with A Massive Ectopic Parathyroid Gland

ObjectiveTo report a rare case of primary hyperparathyroidism presenting with hyper-parathyroid crisis due to parathyroid hyperplasia with ectopic glands.MethodsWe present the initial clinical manifestations, laboratory results, radiologic and surgical findings, and management in a patient who had hyper-parathyroid crisis. The pertinent literature and management options are also reviewed.ResultsA 60-year-old female presented with hyper-parathyroid crisis requiring preoperative stabilization with rehydration, diuresis, bisphosphonate therapy, and ultimately hemodialysis. Parathyroidectomy revealed asymmetric 4-gland hyperplasia, with a massive ectopic parathyroid gland in the tracheoesophageal groove extending into the mediastinum. Her postoperative course was complicated by hungry bone syndrome and hypocalcemia.ConclusionThis case illustrates the rare occurrence of hyper-parathyroid crises due to asymmetric parathyroid hyperplasia with a massive ectopic parathyroid gland. (Endocr Pract. 2014;20:e180-e182)     

Correlating Pre-Operative Vitamin D Status with Post-Thyroidectomy Hypocalcemia

Objective: To examine the relationship between pre-operative vitamin D status and post-thyroidectomy hypocalcemia.Methods: Retrospective study examining 264 total and completion thyroidectomies conducted between 2007 and 2011. Subjects included had a recorded 25-hydroxyvitamin D (25[OH]D) level within 21 days prior to or 1 day following surgery, did not have a primary parathyroid gland disorder, and were not taking 1,25-dihydroxyvitamin D₃ (calcitriol) prior to surgery. Some subjects were repleted with vitamin D pre-operatively if a low 25(OH)D level (typically below 20 ng/mL) was identified. Pre-operative 25(OH)D, concurrent neck dissection, integrity of parathyroid glands, final pathology, postoperative parathyroid hormone (PTH), calcium nadir and repletion, and length of stay were examined.Results: The mean pre-operative 25(OH)D for all subjects was 25 ng/mL, and the overall rate of post-operative hypocalcemia was 37.5%. Lower pre-operative 25(OH)D did not predict postoperative hypocalcemia (P =.96); however, it did predict the need for postoperative 1,25-dihydroxyvitamin D₃ administration (P =.01). Lower postoperative PTH levels (P =.001) were associated with postoperative hypocalcemia.Conclusion: Pre-operative 25(OH)D did not predict a postoperative decrease in serum calcium, although it did predict the need for 1,25-dihydroxyvitamin D₃ therapy in hypocalcemic subjects. We recommend that 25(OH)D be assessed and, if indicated, repleted pre-operatively in patients undergoing total thyroidectomy.Abbreviations: 25(OH)D = 25-hydroxyvitamin D PTH = parathyroid hormone     

Proton Pump Inhibitor-Induced Hypocalcemic Seizure in A Patient with Hypoparathyroidism

ObjectiveTo report a case of proton pump inhibitor-induced hypocalcemic seizure in a patient with hypoparathyroidism.MethodsWe describe the clinical history, physical examination findings, and laboratory values of the patient and briefly review the relevant literature.ResultsA 48-year-old woman with a history of postsurgical hypoparathyroidism who was taking calcium carbonate, 1500 mg 3 times daily, and cholecalciferol, 1200 IU daily, presented with a generalized seizure in the setting of hypocalcemia 12 days after initiating therapy with the proton pump inhibitor lansoprazole. Physical examination revealed a positive Chvostek sign. Electrocardiogram was notable for a prolonged QT_c interval of 576 milliseconds. Laboratory data were notable for the following values: total serum calcium, 5.3 mg/dL; ionized calcium, 2.51 mg/dL; and intact parathyroid hormone, 5.8 pg/mL. The patient’s condition responded to therapy with intravenous calcium gluconate, oral calcium carbonate, and calcitriol. As an outpatient she remained asymptomatic off lansoprazole, treated with calcium carbonate and calcitriol.ConclusionsCaution should be exercised in prescribing proton pump inhibitors to patients with a history of hypoparathyroidism treated with calcium carbonate supplementation because severe hypocalcemia is a potential adverse effect. (Endocr Pract. 2011;17:104-107)