Teriparatide (rhPTH) treatment in children with syndromic hypoparathyroidism

Exploring Chronic Hypocalcemia: Insights into Autoimmune Polyglandular Syndrome Type 1-A Case Study and Literature Review

Hypocalcemia is a common occurrence in pediatric patients, attributed to various causes and presenting with diverse clinical manifestations. A prompt evaluation is necessary to determine its underlying cause, whether it presents acutely or chronically, and to tailor treatment based on its severity. Among the potential causes of chronic hypocalcemia, primary hypoparathyroidism stands out. The case of a seven-year-old male patient with hypocalcemia reported in this article serves as an illustration, wherein targeted next-generation sequencing revealed a homozygous p.R257X mutation in the AIRE gene, indicative of autoimmune polyendocrine syndrome type 1 (APS-1). It poses challenges due to its multisystemic nature and involvement of specific autoantibodies, often leading to underdiagnosis, owing to its rarity, varied manifestations, and incomplete penetrance. A comprehensive review of the APS-1 literature was conducted to provide insights into the clinical manifestations, genetic spectrum, potential immunological mechanisms, and current medical strategies. Additionally, the recognition of AIRE gene mutations is crucial for facilitating genetic diagnosis, prognosis, and potential treatment strategies for APS-1. The management of such cases involves individualized approaches to treatment, regular monitoring, medication adjustments, and the early identification of associated conditions.

Management of Hypoparathyroidism

Hypoparathyroidism (HypoPT) is a rare disorder characterized by hypocalcemia in the presence of a low or inappropriately normal parathyroid hormone level. HypoPT is most commonly seen after neck surgery, which accounts for approximately 75% of cases, whereas approximately 25% have HypoPT due to nonsurgical causes. In both groups of patients, conventional therapy includes calcium and active vitamin D analogue therapy aiming to maintain serum calcium concentration in the low normal or just below the normal reference range and normalize serum phosphorus, magnesium concentrations, and urine calcium levels. The limitations of conventional therapy include wide fluctuations in serum calcium, high pill burden, poor quality of life, and renal complications. Parathyroid hormone (PTH) replacement therapy may improve the biochemical profile in those in whom conventional therapy proves unsatisfactory. Based on a systematic review and meta-analysis of the literature, the panel made a graded recommendation suggesting conventional therapy as first line therapy rather than administration of PTH (weak recommendation, low quality evidence). When conventional therapy is deemed unsatisfactory, the panel considers use of PTH. Because pregnancy and lactation are associated with changes in calcium homeostasis, close monitoring is required during these periods with appropriate adjustment of calcium and active vitamin D analogue therapy to ensure that serum calcium remains in the mid to low normal reference range in order to avoid maternal and fetal complications. Emerging therapies include molecules with prolonged PTH action as well as different mechanisms of action that may significantly enhance drug efficacy and safety. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Evaluation and Management of Hypoparathyroidism Summary Statement and Guidelines from the Second International Workshop

This clinical practice guideline addresses the prevention, diagnosis, and management of hypoparathyroidism (HypoPT) and provides evidence-based recommendations. The HypoPT task forces included four teams with a total of 50 international experts including representatives from the sponsoring societies. A methodologist (GG) and his team supported the taskforces and conducted the systematic reviews. A formal process following the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology and the systematic reviews provided the structure for seven of the guideline recommendations. The task force used a less structured approach based on narrative reviews for 20 non-GRADEd recommendations. Clinicians may consider postsurgical HypoPT permanent if it persists for >12 months after surgery. To predict which patients will not develop permanent postsurgical HypoPT, we recommend evaluating serum PTH within 12 to 24 hours post total thyroidectomy (strong recommendation, moderate quality evidence). PTH > 10 pg/mL (1.05 pmol/L) virtually excludes long-term HypoPT. In individuals with nonsurgical HypoPT, genetic testing may be helpful in the presence of a positive family history of nonsurgical HypoPT, in the presence of syndromic features, or in individuals younger than 40 years. HypoPT can be associated with complications, including nephrocalcinosis, nephrolithiasis, renal insufficiency, cataracts, seizures, cardiac arrhythmias, ischemic heart disease, depression, and an increased risk of infection. Minimizing complications of HypoPT requires careful evaluation and close monitoring of laboratory indices. In patients with chronic HypoPT, the panel suggests conventional therapy with calcium and active vitamin D metabolites as first-line therapy (weak recommendation, low-quality evidence). When conventional therapy is deemed unsatisfactory, the panel considers the use of PTH. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Safety and Efficacy of PTH 1-34 and 1-84 Therapy in Chronic Hypoparathyroidism: A Meta-Analysis of Prospective Trials

Hypoparathyroidism is the only endocrine deficiency for which hormone replacement therapy is not the standard of care. Although conventional treatments may control hypocalcaemia, other complications such as hyperphosphatemia, kidney stones, peripheral calcifications, and bone disease remain unmet needs. This meta-analysis (PROSPERO registration number CRD42019126881) aims to evaluate and compare the efficacy and safety of PTH_1-34 and PTH_1-84 in restoring calcium metabolism in chronic hypoparathyroidism. EMBASE, PubMed, and CENTRAL databases were searched for randomized clinical trials or prospective studies published between January 1996 and March 2021. English-language trials reporting data on replacement with PTH_1-34 or PTH_1-84 in chronic hypoparathyroidism were selected. Three authors extracted outcomes, one author performed quality control, all assessed the risk of biases. Overall, data from 25 studies on 588 patients were analyzed. PTH therapy had a neutral effect on calcium levels, while lowering serum phosphate (-0.21 mmol/L; 95% confidence interval [CI], -0.31 to -0.11 mmol/L; p < 0.001) and urinary calcium excretion (-1.21 mmol/24 h; 95% CI, -2.03 to -0.41 mmol/24 h; p = 0.003). Calcium phosphate product decreased under PTH_1-84 therapy only. Both treatments enabled a significant reduction in calcium and calcitriol supplementation. PTH therapy increased bone turnover markers and lumbar spine mineral density. Quality of life improved and there was no difference in the safety profile between PTH and conventionally treated patients. Results for most outcomes were similar for the two treatments. Limitations of the study included considerable population overlap between the reports, incomplete data, and heterogeneity in the protocol design. In conclusion, the meta-analysis of data from the largest collection to date of hypoparathyroid patients shows that PTH therapy is safe, well-tolerated, and effective in normalizing serum phosphate and urinary calcium excretion, as well as enabling a reduction in calcium and vitamin D use and improving quality of life. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Improving management of severe hypoparathyroidism: a case series

INTRODUCTION

Hypoparathyroidism is considered a rare endocrine disease. Despite being a deficiency of parathyroid hormone, the standard therapy is based on oral calcium and active vitamin D supplementation. This approach provides satisfactory management in most cases but may be inadequate for patients in the most complex spectrum of the disease. Other therapies are being explored, and among them, the use of recombinant human parathyroid hormone (PTH) has proved to decrease the requirements of calcium and active vitamin D to reach adequate therapeutic goals.

OBJECTIVE

We aimed to provide information on the effectiveness of the current recombinant parathyroid hormone analogs in the clinical management of difficult to control cases of hypoparathyroidism.

METHOD AND MATERIALS

We report our experience using teriparatide and PTH (1-84) through five complex cases of hypoparathyroidism of diverse etiologies. We describe each case and report the effectiveness of treatment in clinical practice.

RESULTS

Four patients with postsurgical hypoparathyroidism and one patient with autoimmune hypoparathyroidism, all of them with suboptimal control under the standard treatment with calcium and calcitriol supplements or calcium gluconate infusion, are presented. They were all started on teriparatide or PTH (1-84), and all of them showed a diminishment of symptoms and were able to maintain normocalcemia without parenteral calcium despite a reduction of oral treatment.

CONCLUSION

This article highlights the effectiveness and safety of hormonal replacement treatment in difficult to manage hypoparathyroidism and provides evidence which justifies its off-label prescription in the case of teriparatide. We consider that this treatment should be considered in cases in which standard treatment fails to reach adequate therapeutic goals.

Palatoschisis, Schizophrenia and Hypocalcaemia: Phenotypic Expression of 22q11.2 Deletion Syndrome (DiGeorge Syndrome) in an Adult

22q11.2 deletion syndrome typically presents with congenital cardiac anomalies, immunodeficiencies and hypoparathyroidism. However, clinical findings vary greatly. We present the case of a 56-year-old man, with a history of cleft palate and schizophrenia, who was newly diagnosed with 22q11.2 deletion syndrome during an episode of hypocalcaemia. The syndrome is caused by developmental abnormalities of the embryonic pharyngeal arch system. Treatment of hypocalcaemia with oral calcium and vitamin D is usually sufficient.

LEARNING POINTS

22q11.2 deletion syndrome typically presents with congenital cardiac anomalies, immunodeficiencies and hypoparathyroidism.The syndrome has a variable phenotypic expression and can therefore remain unrecognised in adult patients with mild symptoms.22q11.2 deletion syndrome should be borne in mind, particularly as regards adult psychiatric patients.

Intermittent Bi-Daily Sub-cutaneous Teriparatide Administration in Children With Hypoparathyroidism: A Single-Center Experience

Introduction: The use of teriparatide has been reported in children with hypoparathyroidism as an investigational physiologic replacement therapy. Methods: We aimed to retrospectively report our pediatric experience of bi-daily sub-cutaneous teriparatide. Results are presented as median (25th-75th quartile). As part of the routine follow-up of these patients with hypoparathyroidism, total calcium at H0 (i.e., just before injection) and H4 (i.e., 4 h after teriparatide injection) and other biomarker parameters were regularly assessed. Results: At a median age of 10.7 (8.1-12.6) years, an estimated glomerular filtration rate (eGFR) of 110 (95-118) mL/min/1.73 m², calcium levels of 1.87 (1.81-1.96) mmol/L and an age-standardized phosphate of 3.8 (2.5-4.9) SDS, teriparatide therapy was introduced in 10 patients at the dose of 1.1 (0.7-1.5) μg/kg/day (20 μg twice daily), with further adjustment depending on calcium levels. Six patients already displayed nephrocalcinosis. Severe side effects were reported in one child: two episodes of symptomatic hypocalcemia and one of iatrogenic hypercalcemia; one teenager displayed dysgueusia. Calcium levels at H0 did not significantly increase whilst calcium at H4 and phosphate levels significantly increased and decreased, respectively. After 12 months, eGFR, calcium and age-standardized phosphate levels were 108 (90-122) mL/min/1.73 m², 2.36 (2.23-2.48) mmol/L, 0.5 (-0.1 to 1.5), and 68 (63-74) nmol/L, respectively, with a significant decrease in phosphate levels (p = 0.01). Urinary calcium and calcium/creatinine ratio remained stable; no nephrolithiasis was observed but two moderate nephrocalcinosis appeared. Conclusion: Intermittent teriparatide therapy significantly improves calcium and phosphate control, without increasing calciuria. It appears to be safe and well-tolerated in children.

Parathyroid Hormone Replacement versus Oral Calcium and Active Vitamin D Supplementation in Hypoparathyroidism: A Meta-analysis

OBJECTIVES

Chronic hypoparathyroidism is treated conventionally with active vitamin D and high doses of calcium. Recombinant human parathyroid hormone (PTH) replacement is an attractive option for treating patients with hypoparathyroidism since it can replace the physiological action of native PTH. The aim of our study was to perform a comprehensive evaluation of the effects of PTH replacement on calcium homeostasis, bone metabolism, and daily requirement of calcium and active vitamin D.

MATERIALS AND METHODS

Randomized controlled trials done in chronic hypoparathyroid patients were included in this meta-analysis. The PTH group included subjects receiving a subcutaneous injection of either PTH (1-84) or PTH (1-34) with oral calcium and/or active vitamin D. The control group included those receiving oral calcium and active vitamin D with/without subcutaneous placebo injection. The primary outcome of this meta-analysis was to compare serum calcium, 24-h urinary calcium, and severe adverse effects among PTH and control groups.

RESULTS

In this meta-analysis, we did not find any difference in serum calcium level between PTH and control groups [mean difference (MD) - 0.01; 95% confidence interval (CI) - 0.09, 0.06; P = 0.71]. Although there was a trend towards low 24-h urinary calcium in the PTH group, the difference was not statistically significant (MD - 1.43; 95% CI - 2.89, 0.03; P = 0.06). The incidence of serious adverse events was also similar in both groups (RR 1.35; 95% CI 0.58, 3.16; P = 0.49).

CONCLUSION

Both PTH and active vitamin D therapies are associated with comparable serum and urine calcium levels with a similar incidence of serious adverse events in patients with chronic hypoparathyroidism.

Afebrile Seizures as Initial Symptom of Hypocalcemia Secondary to Hypoparathyroidism

Hypocalcemia is rare in childhood and caused, among other conditions, by hypoparathyroidism. DiGeorge syndrome is the most common cause of hypoparathyroidism in childhood. Presentation of a rare cause of hypocalcemia in childhood and the necessity of measuring serum electrolyte levels in patients presenting with afebrile seizures. a 7.5-year-old female child presented with afebrile seizures lasting 5 min with postictal drowsiness. A similar episode 1 month ago is described. On admission, a positive Trousseau sign, papilledema, and long QTc on electrocardiography were detected. Laboratory testing revealed hypocalcemia, increased creatine phosphokinase and phosphate levels, decreased levels of parathormone, with normal thyroid function and normal levels of blood gases. considering the diagnosis of hypoparathyroidism possible, we started on calcium gluconate solution 5% intravenously and calcium carbonate per os. 48 h later, the child transferred to tertiary hospital for further evaluation. The laboratory findings revealed 25-OH Vitamin D deficiency with normal cortisol levels and the absence of autoantibodies. Kidney and brain imaging and also the electroencephalogram were normal. Calcium carbonate, magnesium, and Vitamin D were administered per os. The child discharged from hospital with complete resolution of symptoms. Since then, she is in treatment with calcium carbonate and Vitamin D per os. Hypoparathyroidism is rare in childhood. We underline the necessity of measuring serum electrolyte levels in patients presenting with afebrile seizures.

Short-Term PTH(1-34) Therapy in Children to Correct Severe Hypocalcemia and Hyperphosphatemia due to Hypoparathyroidism: Two Case Studies

The standard treatment of hypoparathyroidism is to control hypocalcemia using calcitriol and calcium supplementation. However, in severe cases this approach is insufficient, and the risks of intravenous (i.v.) calcium administration and prolonged hospitalization must be considered. While the use of recombinant human parathyroid hormone 1-34 [rhPTH(1-34)] for long-term control of hypocalcemia has been established, the benefits of short-term rhPTH(1-34) treatment in children have not been explored. We report two patients with hypoparathyroidism treated with rhPTH(1-34). Patient 1 is a 10-year-old female with polyglandular autoimmune syndrome type 1. Patient 2 is a 12-year-old female with hypoparathyroidism after total thyroidectomy. Both patients showed poor response to i.v. and oral calcium and calcitriol, and patient 1 did not respond to phosphate binders. Patient 1 had rapid increase in serum calcium with a decrease in serum phosphate after a 3-day course of subcutaneous rhPTH(1-34). Patient 2 had normalization of calcium and phosphate levels after a 7-day course of rhPTH(1-34). These cases support a role for rhPTH(1-34) in the acute management of hypoparathyroidism in hospitalized patients to more rapidly correct hypocalcemia and hyperphosphatemia, shorten hospitalization, and reduce the need for frequent i.v. calcium boluses.

22q11 deletion syndrome: current perspective

Chromosome 22q11 is characterized by the presence of chromosome-specific low-copy repeats or segmental duplications. This region of the chromosome is very unstable and susceptible to mutations. The misalignment of low-copy repeats during nonallelic homologous recombination leads to the deletion of the 22q11.2 region, which results in 22q11 deletion syndrome (22q11DS). The 22q11.2 deletion is associated with a wide variety of phenotypes. The term 22q11DS is an umbrella term that is used to encompass all 22q11.2 deletion-associated phenotypes. The haploinsufficiency of genes located at 22q11.2 affects the early morphogenesis of the pharyngeal arches, heart, skeleton, and brain. TBX1 is the most important gene for 22q11DS. This syndrome can ultimately affect many organs or systems; therefore, it has a very wide phenotypic spectrum. An increasing amount of information is available related to the pathogenesis, clinical phenotypes, and management of this syndrome in recent years. This review summarizes the current clinical and genetic status related to 22q11DS.

Underweight, overweight, and pediatric bone fragility: impact and management

Skeletal health is modulated by a variety of factors, including genetic makeup, hormonal axes, and environment. Across all ages, extremes of body weight may exert a deleterious effect on bone accretion and increase fracture risk. The incidence of both anorexia nervosa and obesity, each involving extreme alterations in body composition, is rising among youth, and secondary osteoporosis is increasingly being diagnosed among affected children and adolescents. Compared with the elderly, the definition of osteoporosis that stems from any underlying condition differs for the pediatric population and special precautions are required with regard to treatment of young patients. Early recognition and management of both underweight and overweight youth and the accompanying consequences on bone and mineral metabolism are essential for preservation of skeletal health, although prevention of bone loss and optimization of bone mineral accrual remain the most important protective measures.