Background. Adequate intake of vitamin D and its concentration in serum is important for the health of bones and calcium-phosphorus metabolism and for the optimal functioning of many organs and tissues. Most epidemiological studies have shown that vitamin D deficiency is widespread among the population in Russian Federation. Material and methods. We reviewed relevant literature on the epidemiology of insufficiency and deficiency, skeletal and extraskeletal effects of vitamin D and summarized recommendations for the diagnosis, prevention and treatment of vitamin D deficiency in the general population, which were subsequently discussed and amended in conjunction with leading endocrinologists of the Russian Federation who are experts in this subject. Results. The optimal concentration of 25(OH)D in the serum as the best indicator of vitamin D body stores is recognized as 30—100 ng/ml (75—250 nmol/l), insufficiency — from 20 to 30 ng/ml (50 to 75 nmol/l), deficiency — less than 20 ng/ml (less than 50 nmol/l). In prevention and treatment it is recommended to stick to the target serum levels of 25(OH)D in the range of 30—60 ng/ml (75—150 nmol/l). We’ve developed a general practice recommendations for the prevention, diagnosis and treatment of vitamin D deficiency in adults, including pregnant and lactating women, persons over 50 years old and subjects suffering from various diseases affecting the metabolism of vitamin D. Conclusions. Increased sufficiency of vitamin D in the population should be included as one of the priorities of modern healthcare due to proven preventive health effects on the musculoskeletal system and the potential positive impact on many socially significant diseases. This publication is a detailed version of the Federal Guideline.

Терапевтические возможности коррекции дефицита витамина d у взрослых

Primary hyperparathyroidism (PHPT) is an endocrine disorder of parathyroid glands characterized by excessive secretion of parathyroid hormone (PTH) with an upper normal or elevated blood calcium level. Classical PHPT refers to a symptomatic, multi-system disorder, wich can lead to a significant decrease in the quality of life, disability of patients, and even an increased risk of premature death. Hypercalcemia and the catabolic effect of PTH on various cells are considered as the main pathogenetic mechanisms of the PHPT associated complications. In the last two decades, there has been an increase in the incidence of PHPT, mainly due to the mild forms of the disease, primarily due to the routine calcium screening in North America, Western Europe and, Asia. High prevalence of the disease, as well as the variety of clinical manifestations, cause the attention of different specialists - physicians, rheumatologists, urologists, nephrologists, cardiologists and other doctors. This review cover the main issues of Russian guidelines for the management of PHPT, approved in 2020, including laboratory and instrumental methods, differential diagnosis, surgical and conservative approach, short-term and long-term follow-up. This guidelines also include the recommendations for special groups of patients with hereditary forms of PHPT, parathyroid carcinoma, PHPT during pregnancy.

/pdf/the-clinical-practice-guidelines-for-primary-37krbzp0i7.pdf

[The clinical practice guidelines for primary hyperparathyroidism, short version].

Importance
Hypercalcemia affects approximately 1% of the worldwide population. Mild hypercalcemia, defined as total calcium of less than 12 mg/dL (<3 mmol/L) or ionized calcium of 5.6 to 8.0 mg/dL (1.4-2 mmol/L), is usually asymptomatic but may be associated with constitutional symptoms such as fatigue and constipation in approximately 20% of people. Hypercalcemia that is severe, defined as total calcium of 14 mg/dL or greater (>3.5 mmol/L) or ionized calcium of 10 mg/dL or greater (≥2.5 mmol/L) or that develops rapidly over days to weeks, can cause nausea, vomiting, dehydration, confusion, somnolence, and coma.


Observations
Approximately 90% of people with hypercalcemia have primary hyperparathyroidism (PHPT) or malignancy. Additional causes of hypercalcemia include granulomatous disease such as sarcoidosis, endocrinopathies such as thyroid disease, immobilization, genetic disorders, and medications such as thiazide diuretics and supplements such as calcium, vitamin D, or vitamin A. Hypercalcemia has been associated with sodium-glucose cotransporter 2 protein inhibitors, immune checkpoint inhibitors, denosumab discontinuation, SARS-CoV-2, ketogenic diets, and extreme exercise, but these account for less than 1% of causes. Serum intact parathyroid hormone (PTH), the most important initial test to evaluate hypercalcemia, distinguishes PTH-dependent from PTH-independent causes. In a patient with hypercalcemia, an elevated or normal PTH concentration is consistent with PHPT, while a suppressed PTH level (<20 pg/mL depending on assay) indicates another cause. Mild hypercalcemia usually does not need acute intervention. If due to PHPT, parathyroidectomy may be considered depending on age, serum calcium level, and kidney or skeletal involvement. In patients older than 50 years with serum calcium levels less than 1 mg above the upper normal limit and no evidence of skeletal or kidney disease, observation may be appropriate. Initial therapy of symptomatic or severe hypercalcemia consists of hydration and intravenous bisphosphonates, such as zoledronic acid or pamidronate. In patients with kidney failure, denosumab and dialysis may be indicated. Glucocorticoids may be used as primary treatment when hypercalcemia is due to excessive intestinal calcium absorption (vitamin D intoxication, granulomatous disorders, some lymphomas). Treatment reduces serum calcium and improves symptoms, at least transiently. The underlying cause of hypercalcemia should be identified and treated. The prognosis for asymptomatic PHPT is excellent with either medical or surgical management. Hypercalcemia of malignancy is associated with poor survival.


Conclusions and Relevance
Mild hypercalcemia is typically asymptomatic, while severe hypercalcemia is associated with nausea, vomiting, dehydration, confusion, somnolence, and coma. Asymptomatic hypercalcemia due to primary hyperparathyroidism is managed with parathyroidectomy or observation with monitoring, while severe hypercalcemia is typically treated with hydration and intravenous bisphosphonates.

Hypercalcemia: A Review.

Hypercalcemia affects approximately 1% of the worldwide population. Mild hypercalcemia, defined as total calcium of less than 12 mg/dL (&lt;3 mmol/L) or ionized calcium of 5.6 to 8.0 mg/dL (1.4-2 mmol/L), is usually asymptomatic but may be associated with constitutional symptoms such as fatigue and constipation in approximately 20% of people. Hypercalcemia that is severe, defined as total calcium of 14 mg/dL or greater (&gt;3.5 mmol/L) or ionized calcium of 10 mg/dL or greater (≥2.5 mmol/L) or that develops rapidly over days to weeks, can cause nausea, vomiting, dehydration, confusion, somnolence, and coma.Approximately 90% of people with hypercalcemia have primary hyperparathyroidism (PHPT) or malignancy. Additional causes of hypercalcemia include granulomatous disease such as sarcoidosis, endocrinopathies such as thyroid disease, immobilization, genetic disorders, and medications such as thiazide diuretics and supplements such as calcium, vitamin D, or vitamin A. Hypercalcemia has been associated with sodium-glucose cotransporter 2 protein inhibitors, immune checkpoint inhibitors, denosumab discontinuation, SARS-CoV-2, ketogenic diets, and extreme exercise, but these account for less than 1% of causes. Serum intact parathyroid hormone (PTH), the most important initial test to evaluate hypercalcemia, distinguishes PTH-dependent from PTH-independent causes. In a patient with hypercalcemia, an elevated or normal PTH concentration is consistent with PHPT, while a suppressed PTH level (&lt;20 pg/mL depending on assay) indicates another cause. Mild hypercalcemia usually does not need acute intervention. If due to PHPT, parathyroidectomy may be considered depending on age, serum calcium level, and kidney or skeletal involvement. In patients older than 50 years with serum calcium levels less than 1 mg above the upper normal limit and no evidence of skeletal or kidney disease, observation may be appropriate. Initial therapy of symptomatic or severe hypercalcemia consists of hydration and intravenous bisphosphonates, such as zoledronic acid or pamidronate. In patients with kidney failure, denosumab and dialysis may be indicated. Glucocorticoids may be used as primary treatment when hypercalcemia is due to excessive intestinal calcium absorption (vitamin D intoxication, granulomatous disorders, some lymphomas). Treatment reduces serum calcium and improves symptoms, at least transiently. The underlying cause of hypercalcemia should be identified and treated. The prognosis for asymptomatic PHPT is excellent with either medical or surgical management. Hypercalcemia of malignancy is associated with poor survival.Mild hypercalcemia is typically asymptomatic, while severe hypercalcemia is associated with nausea, vomiting, dehydration, confusion, somnolence, and coma. Asymptomatic hypercalcemia due to primary hyperparathyroidism is managed with parathyroidectomy or observation with monitoring, while severe hypercalcemia is typically treated with hydration and intravenous bisphosphonates.

Hypercalcemia

Parathyroid carcinoma is a rare disease leading to severe hypercalcemia due to hyperparathyroidism. Surgery is the primary treatment option. A more progressive form of the disease is characterized by parathyrotoxicosis, and subsequent hypercalcemia is the most common cause of death. We report a case presenting with severe hypercalcemia due to parathyrotoxicosis from parathyroid carcinoma treated for the first time using the monoclonal antibody denosumab as a rescue therapy and present long-term follow-up data. The 71-year-old patient presented with severe hypercalcemia due to metastatic parathyroid carcinoma. Despite undergoing treatment with bisphosphonates, cinacalcet hydrochloride, and forced diuresis, the patient`s condition deteriorated rapidly due to resistant hypercalcemia. Surgery performed because of spinal metastasis and forced diuresis lowered calcium levels, albeit they remained in the hypercalcemic range and significantly increased when forced diuresis was stopped. Considering a palliative situation to overcome hypercalcemia, we decided to administer denosumab, a monoclonal antibody that binds to the receptor activator of nuclear factor-kappa B ligand. After a single subcutaneous administration of 60 mg denosumab, calcium levels normalized within one day. Subsequent denosumab injections led to permanent control of serum calcium for more than 2 years despite rising parathyroid hormone levels and repeated surgeries. Together with recent cases in the literature supporting our observation, we believe that denosumab is relevant for future trials and represents an effective tool to control hypercalcemia in patients with advanced stages of parathyroid cancer. Learning points Severe hypercalcemia is the most common cause of death in patients with parathyroid carcinoma. The monoclonal antibody denosumab rapidly lowered severely elevated serum calcium levels due to parathyrotoxicosis. Denosumab was effective in the long-term treatment of hypercalcemia despite progression of parathyroid carcinoma.

ckert JC, Palliative treatment of uncontrollable hypercalcemia due to parathyrotoxicosis: denosumab as rescue therapy.

Hypercalcemic crisis is a severe but rare complication of primary hyperparathyroidism (PHPT), and data on denosumab treatment of patients with this disease is still very limited. The aim of this paper is to investigate the hypocalcemic effect of denosumab in PHPT patients with severe hypercalcemia when surgery should be delayed or is impossible for some reasons. We performed a retrospective study of 10 patients. The analysis included the use of biochemical markers of calcium-phosphorus metabolism, which were followed after the administration of 60 mg of denosumab. The trend to calcium reduction was already determined on the 3rd day after denosumab administration. In most cases the decrease in serum calcium level to the range of 2.8 mmol/L on average or lower was observed on the 7th day (P = 0.002). In addition to a significant increase in calcium levels we confirmed a significant increase in the estimated glomerular filtration rate on 7th day (P = 0.012). After that, seven patients underwent successful parathyroidectomy and achieved eucalcemia or hypocalcemia, one patient developed the recurrence of parathyroid cancer after initial surgery, while two patients with severe cardiovascular pathology refused surgery. Our study shows that denosumab is a useful tool in PHPT-associated hypercalcemia before surgery or if surgery is contraindicated.

/pdf/denosumab-for-management-of-severe-hypercalcemia-in-primary-fkcrvpvdhc.pdf

Denosumab for management of severe hypercalcemia in primary hyperparathyroidism.

OBJECTIVE To compare the serum miRNA expression profiles between patients with benign and malignant parathyroid tumours. BACKGROUND Despite recent advances in molecular biology, a histological tissue biopsy is still the method of choice used to diagnose most cancers. The preoperative cytology is not an applicable method for diagnosis of parathyroid cancer (PC); therefore, huge interest exists in terms of finding alternative methodologies to seek specific cancer biomarkers. DESIGN A retrospective cross-sectional study. PATIENTS AND METHODS Serum samples of patients with PC (n = 13) and parathyroid adenoma (PA) (n = 11), age (p = .999) and sex (p = .999) were matched and examined via the simultaneous comparative expression analysis of 754 microRNAs (miRNAs). The «TaqMan OpenArray Human MicroRNA Panel» (Applied Biosystems) was used to conduct real-time PCRs using the «QuantStudio 12К Flex» station (Life Technologies). RESULTS According to the results of a pilot study, significant changes in expression levels between the PC group and the PA group (control) (p < .05) were observed for 17 miRNAs. Among them, the downregulation of miRNA-342-3p met the Benjamini-Hochberg adjustment criteria for multiple comparisons (p = .02). CONCLUSIONS Serum miRNA-342-3p could be a promising biomarker for PC to improve diagnosis and prognosis.

Serum circulating miRNA-342-3p as a potential diagnostic biomarker in parathyroid carcinomas: A pilot study.

Background: there are no specific markers of the parathyroid carcinoma (PC) therefore, the development of algorithms for identifying high-risk patients is an urgent task. 
Aims: to determine the clinical and laboratory predictors of PC and to identify the factors of a poor prognosis. 
Materials and methods: A multicenter retrospective study included 242 patients with primary hyperparathyroidism (PHPT) who were divided into groups: 162 with adenomas, 30 with аtypical adenomas (АА) and 50 patients with PC. Data collection and analysis was carried out from 2017 to 2020. The primary goal assessment of the possibility of PС using preoperative laboratory and instrumental data. The group of PC was divided into subgroups: the patients in recurrences (n=17) and remission (n=33). The level of the total calcium, albumin, alkaline phosphatase (ALP), ionized calcium (Ca ++) in the blood were determined on the automatic biochemical analyzer; the level of parathyroid hormone (PTH) by electrochemoluminescent analyzer. The size of the PG determined by the ellipse formula: V (cm3) = (A B C) 0.49. Statistical analysis was performed with Statistica 13 and SPSS software packages. For multiple comparisons, the Bonferroni correction was applied. 
Results: the group of patients with increased risk of PC include persons with increased level of PTH 443 pg/ml, Ca++ 1.5 mmol/l, total calcium 3.2 mmol/l, ALP 176 IU/L, V of tumors 2.6 cm3, largest size 22.5 mm (p 0,001). Heterogeneous structure is more typical to PC compared to the АА (p = 0,004 and р = 0,011), the same applies to indefinite contour (р = 0,001 и р = 0,011). Pathological mitosis is a prognostically unfavorable factor of recurrence of PC (р=0,007). 
Conclusions: the patients with PC and AA are characterized with more aggressive course of PHPT compared to the group of adenomas.

A retrospective study of the clinical and laboratory predictors and morphological characteristics of the parathyroid carcinoma

Background: mild hypocalcemia is a common laboratory finding that is not accompanied by the clinical symptoms. The most common causes of hypocalcemia are inadequate calcium intake and vitamin D deficiency. Given the high prevalence of vitamin D deficiency (insufficiency), it seems relevant to determine the daily variability of serum calcium levels before and after its supplementation.Aims: to assess the effect of 25(OH) vitamin D level on the daily profile of serum calcium and 24-hour urinary calcium levels. MATERIALS AND METHODS: the interventional, prospective, comparative study of 10 healthy volunteers (women/men - 9/1) was performed. We have analyzed the daily profiles of serum calcium and 24-hour urinary calcium levels. Summary duration of this study was 8 months and consisted two hospitalizations. Statistical analysis was done on August 2020. The descriptive statistics are represented by medians and the first and third quartiles in Me (Q1; Q3), average, maximum, and minimum values M (min; max) and by absolute and relative frequencies.Results: Me serum calcium levels (Catotaland Cacorr.) and 24-hour urinary calcium levels did not differ before and after vitamin D supplementation. However, the number of reference calcium values increased as 25 (OH) vitamin D level was reached more than 30 ng/ml from 90.8% to 100% for Catotal and from 94.2% to 97.5% for Cacorr. Episodes of hypocalcemia were registered in patients with low vitamin D levels: in 3.33% of cases according to Catotal and 5.8% for Cacorr. The frequency of hypocalcemia decreased for Catotal (to 0%) and for Cacorr. (to 2.5%) after treatment with cholecalciferol. Analysis of Catotal and Cacorr. deviations during the day showed a less variability of the calcium profile after treatment, This study also revealed circadian character of daily serum calcium profile with the presence of maximum (09:40-17:40) and minimum (23:40-07:40) values during the day.Conclusions: Our study demonstrated the improvement of daily serum calcium profile after vitamin D supplementation. We confirmed the increased number of reference calcium values, decreased variability of serum calcium levels during the day and decreased frequency of hypocalcemia.

/pdf/influence-of-deficiency-or-insufficiency-of-vitamin-d-on-the-2gxbh71783.pdf

Influence of deficiency or insufficiency of vitamin D on the circadian rhythm of serum calcium level

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9164782

Alina Ajnetdinova

Papers

Denosumab for management of severe hypercalcemia in primary hyperparathyroidism.

Serum circulating miRNA-342-3p as a potential diagnostic biomarker in parathyroid carcinomas: A pilot study.

A retrospective study of the clinical and laboratory predictors and morphological characteristics of the parathyroid carcinoma

Influence of deficiency or insufficiency of vitamin D on the circadian rhythm of serum calcium level

IDF21-0416 Mortality risk factors due to COVID-19 in diabetic patients according to the nationwide diabetes register analysis