Parathyroid hormone independent hypercalcemia in adults

Hyperparathyroidism-induced secondary osteoporosis leading to recurrent non-traumatic vertebral compression fractures: A comprehensive case report

Background

Primary hyperparathyroidism, while increasing the susceptibility to osteoporosis, also amplifies the potential for fractures in vulnerable areas such as the femoral neck. It can also serve as an infrequent etiological factor behind vertebral compression fractures.

Case report

This report discusses a case of multiple acute non-traumatic vertebral compression fractures in a patient diagnosed with primary hyperparathyroidism. The patient, a 79-year-old female with osteopenia (T Score -2.0, medically treated), had a history of left breast cancer treated with a partial mastectomy and radiation therapy. She presented with midline back pain resulting from T12 and L2 compression fractures and underwent balloon kyphoplasty. A week later, she reported severe low back pain, despite the absence of any new traumatic event. Repeat imaging showed multiple new, acute compression fractures at T10, T11, L1, and L3. Further workup revealed elevated parathyroid hormone levels and hypercalcemia, leading to a diagnosis of hyperparathyroidism.

Conclusion

Multiple acute non-traumatic vertebral body compression fractures due to hyperparathyroidism is an uncommon clinical manifestation. This case emphasizes the need for an extended work-up of secondary osteoporosis in patients who experience multiple vertebral compression fractures.

Severe hypercalcemia caused by repeated mineral oil injections: a case report

Hypercalcemia is a frequent condition in clinical practice and when the most frequent causes are excluded, etiological diagnosis can be challenging. A rare cause of PTH-independent hypercalcemia is described in the present case report. A male adult with a history of androgenic-anabolic steroids abuse, and injection of mineral oil and oily veterinary compound containing vitamins A, D and E into muscles for local hypertrophy presented with hypercalcemia, nephrocalcinosis, and end-stage renal disease. On physical examination, the presence of calcified subcutaneous nodules and calcification of musculature previously infused with oily substances drew attention. Laboratory tests confirmed hypercalcemia of 12.62 mg/L, low levels of PTH (10 pg/mL), hyperphosphatemia (6.0 mg/dL), 25(OH)D of 23.3 ng/mL, and elevated 1,25(OH)2D (138 pg/mL). Imaging exams showed diffuse calcification of muscle tissue, subcutaneous tissue, and organs such as the heart, lung, and kidneys. The patient was diagnosed with PTH-independent hypercalcemia secondary to foreign body reaction in areas of oil injection. The patient underwent treatment with hydrocortisone for 10 days, single dose zoledronic acid and hemodialysis. He evolved with serum calcium levels of 10.4 mg/dL and phosphorus of 7.1 mg/dL. In addition, sertraline and quetiapine were prescribed to control body dysmorphic disorder. The medical community should become aware of new causes of hypercalcemia as secondary to oil injection since this should become increasingly frequent due to the regularity with which such procedures have been performed.

Construction and validation of a predictive model for hypocalcemia after parathyroidectomy in patients with secondary hyperparathyroidism

OBJECTIVE

We aimed to construct and validate a predictive model for the risk of hypocalcemia following parathyroidectomy (PTX) for the treatment of secondary(renal) hyperparathyroidism (SHPT).

METHODS

Information regarding patients with SHPT who underwent PTX between January 2019 and April 2022 was collected retrospectively. Univariate and multivariate logistic regression analyses were used to identify independent risk factors for hypocalcemia following PTX and to construct predictive models. The areas under the receiver operating characteristic curve (AUC), the calibration curve, and the clinical decision curve (decision curve analysis, DCA) were used to assess the discrimination, calibration, and level of clinical benefit obtained using the predictive models.

RESULTS

We studied 238 patients who were randomly allocated in a 7:3 ratio to a training group (n=166) and a test group (n=72). Univariate and multivariate logistic regression analyses were performed, in which three variables (the circulating parathyroid hormone (PTH) and Ca concentrations, and alkaline phosphatase (ALP) activity) were interrogated for possible roles as independent risk factors for hypocalcemia in patients with SHPT who undergo PTX, and used to construct predictive models. The AUCs for the constructed models were high for both the training (0.903) and test (0.948) groups. The calibration curve showed good agreement between the incidence of postoperative hypocalcemia estimated using the predictive model and the actual incidence. The DCA curve indicated that the predictive model performed well.

CONCLUSION

A predictive model constructed using a combination of preoperative PTH, Ca, and ALP may represent a useful means of identifying patients with SHPT at high risk of developing hypocalcemia following PTX in clinical practice.

The activity of the renin-angiotensin-aldosterone system before and after parathyroidectomy in patients with primary hyperparathyroidism

Background. The relationships between renin-angiotensin-aldosterone system (RAAS) and elevated parathyroid hormone levels in primary hyperparathyroidism (PHPT) is being actively discussed. But the way how parathyroid hormone interacts with renin and aldosterone currently is not clear. Materials and methods. Forty patients aged 18 to 70 years with a confirmed diagnosis of PHPT were involved in the study. All patients were tested for the main parameters of phosphorus-calcium metabolism and the RAAS parameters (plasma renin, plasma aldosterone) before and 2 weeks after parathyroidectomy. Results. Sixty percent of patients had any cardiovascular disease (CVD) and hypertension was the most common. Patients CVD in comparison with patients without CVD were older (61 and 41 years, respectively; p0.001), had a higher body mass index (28.9 and 21.9 kg/m2, respectively; p0.001) and had a lower aldosterone-to-renin ratio ARR (1.78 and 5.42, respectively; p=0.030). Patients with hypertension were older than patients with normal blood pressure (63 and 41 years, respectively; p0.001), had a higher body mass index (28.1 and 23.5 kg/m2, respectively; p=0.005), a lower ARR (1.46 and 5.82, respectively; p=0.001), as well higher levels of plasma renin (109.2 and 20.3 pg/ml, respectively; p=0.007) and serum total calcium (2.84 and 2.71 mmol/l, respectively; p=0.041). Correlation analysis showed that in patients with PHPT and CVD, the concentration of aldosterone is associated with the level of 24-hour urinary calcium (r=0.829, p=0.042), and in patients with symptomatic PHPT and CVD, the level of aldosterone correlated with the level of ionized calcium (r=-0.812, p=0.05). We found no significant differences between the levels of renin, aldosterone and ARR before and 2 weeks after parathyroidectomy. However, in the postoperative period, there were no differences in the levels of renin and ARR among patients with hypertension and without hypertension. Conclusion. In our study we found that the levels of plasma renin and serum total calcium were higher in patients with PHPT and hypertension compared to patients with normal blood pressure. Also, we found the associations between plasma aldosterone and levels of ionized calcium and 24-hour urinary calcium. But the relationships between RAAS parameters and parameters of phosphorus-calcium metabolism need further investigations.

Imaging features of hypercalcemia: A primer for emergency radiologists

Hypercalcemia is a marker for a wide variety of underlying etiologies, and its presentation in the emergency setting may be asymptomatic, incidental, or a primary complaint with associated symptoms and physical exam findings. While the workup is initially driven through serum laboratory testing, imaging plays an important role in diagnosis and post-treatment follow up. This review covers multiple common and uncommon etiologies of hypercalcemia, details their underlying mechanisms, and identifies the most important associated imaging findings. It is important for radiologists to be familiar with these etiologies and imaging findings, particularly in the emergency setting since hypercalcemia may represent the only significant laboratory abnormality associated with the presenting condition. Furthermore, the radiologist's interpretation of a study may be directly influenced by knowing about a patient's hypercalcemia.

High Expression of Parathyroid Hormone-related Protein and Tumor Necrosis Factor-α in Cancer Cells as Risk Factors for Hypercalcemia in Bone Metastases Lytic Lesions

BACKGROUND: Cancer mortality is more commonly due to metastases of the tumor to other organs and the complications that accompany it than the tumor growth itself. Until recently, metastasis has been an insurmountable problem. AIM: As the most frequent site of metastases, apart from the lungs and liver, tumor metastases to bone are associated with hypercalcemia which is fatal for the affected patient. METHODS: This study used a case-control study design. The case group consisted of paraffin block samples derived from bone metastatic cancer cell biopsies of patients with hypercalcemic lytic lesions. The control group consisted of paraffin block samples derived from bone metastatic cancer cell biopsies of patients with non-hypercalcemic lytic lesions. Radiological examination was performed to examine the presence of lytic lesions, followed by data collection of serum calcium levels. The data obtained from the histopathological examination was confirmed along with the availability of paraffin blocks of bone metastasis cancer cell biopsy samples, and immunohistochemical analysis was performed to determine the expression of tumor necrosis factor-α _(TNF-α) and parathyroid hormone-related protein (PTHrP). A Mann–Whitney test was performed to determine the expression of TNF-α _and PTHrP between hypercalcemia and non-hypercalcemia groups. To identify the cut-off point, Youden index on receiver operating characteristic was used, then the optimal cut-off point was determined where the sensitivity and specificity curves intersect. Analysis of risk factor assessment was done by creating a 2 × 2 cross-tabulations and calculating the association size in the form of odds ratio (OR). RESULTS: The expression of PTHrP and TNF-α _in the case group was significantly different from the control group with p < 0.05. The cut-off point for PTHrP expression was 267.5 with an area under the curve of 0.93, indicating a high accuracy value. The cut-off point for TNF-α _expression was 227.5 with an area under the curve of 0.68, indicating a moderate accuracy value. The OR between hypercalcemia and non-hypercalcemia to PTHrP expression was 110.3 (Fisher’s exact statistical test obtained p < 0.05), while the OR between hypercalcemia and non-hypercalcemia to TNF-α _expression was 7.27 (Fisher’s exact test statistical obtained p = 0.01). CONCLUSION: Significant differences in the expression of PTHrP and TNF-α _were found between patients with bone metastases lytic lesions with hypercalcemia compared to those without hypercalcemia. We can conclude that either a high level of PTHrP expression and/or TNF-α _expression in cancer cells can serve as risk factors for hypercalcemia in patients with bone metastatic lytic lesions.

PTHR1 in osteosarcoma: Specific molecular mechanisms and comprehensive functional perspective

Osteosarcoma occurs largely in children and adolescents and is the most common primary malignant tumour of bone. Although surgical advances and neoadjuvant chemotherapy have made great strides in recent years, rates of local recurrence and lung metastasis remain high, with a plateau in overall survival during the past decade. It is thus urgent to explore the pathogenesis of osteosarcoma and identify potential therapeutic targets. Parathyroid hormone receptor 1 (PTHR1) belongs to the broad family of G protein–coupled receptors, binding both parathyroid hormone (PTH) and parathyroid hormone–related peptide (PTHrP, a paracrine factor). Previous studies have shown that in tissues and cells of osteosarcoma, expression of PTHR1 is markedly increased, correlating with aggressive biologic behaviour and a poor prognosis. PTHR1 expression also correlates closely with epigenetic regulation, transcriptional regulation, post‐translational modification and protein interaction. Herein, we have summarized the latest research on the role played by PTHR1 in progression of osteosarcoma, assessing its clinical utility as a novel biomarker and its therapeutic ramifications.

Particle disease: a unique cause of hypercalcemia

Hypercalcemia as a result of ectopic 1, 25-dihydroxyvitamin D (1,25-(OH)₂ D) production has been well-described in sarcoidosis and other granulomatous diseases. The 1-alpha-hydroxylase enzyme in activated macrophages is not subject to physiologic regulations, resulting in hypercalcemia with inappropriately normal or elevated 1,25-(OH) ₂ D. Particle disease is the local inflammatory response provoked by an overwhelming production of wear debris from a failed joint prosthesis. Enhanced focal bone resorption in particle disease has been described due to local production of inflammatory cytokines. However, this process previously has not been reported to cause hypercalcemia. We describe a patient with hypercalcemia, low parathyroid hormone levels, and elevated 1,25-(OH)₂ D whose failed prosthetic joint generated a large amount of inflammatory debris, forming a soft tissue mass with lymphadenopathy. Biopsy of the mass demonstrated activated macrophages and foreign body granuloma, resulting in unregulated production of 1,25-(OH)₂ D and hypercalcemia. We present the first case of hypercalcemia associated with elevated 1,25-(OH)₂ D in particle disease due to a failed prosthetic hip.

Effects of PTH and PTH Hypersecretion on Bone: a Clinical Perspective

PURPOSE OF REVIEW

Hyperparathyroidism may be due to an autonomous hypersecretion of parathyroid hormone (PTH) or occurs in response to a number of physiological stimuli. A number of recent findings have provided new insights into the importance of the calcium-parathyroid-vitamin D axis to bone in normal physiology and pathological conditions.

RECENT FINDINGS

PTH is known to affect bone microarchitecture with different effects on cortical and trabecular bone compartments. In trabecular bone, PTH may exert anabolic effects, whereas PTH promotes bone resorption in cortical bone. Vertebral fractures are prevalent in primary hyperparathyroidism (PHPT), and patients seem to fracture at higher values of bone mineral density (BMD) than patients with osteoporosis. This may be explained by changes in bone microarchitecture, which cannot be detected by measuring BMD. Even in mild PHPT, bone seems to benefit from parathyroidectomy. In secondary hyperparathyroidism, bone seems much more susceptible to fracture with insufficient levels of vitamin D compared with a replete vitamin status. If elevated PTH levels cannot be explained by conditions known to cause secondary hyperparathyroidism, the condition is termed normocalcemic PHPT, which also has been associated with an increased risk of fractures. Hyperparathyroidism is harmful to bone, which is why it is of importance to normalize PTH levels either by parathyroidectomy in PHPT or by counteracting conditions known to increase PTH in secondary hyperparathyroidism.

Cardiovascular consequences of parathyroid disorders in adults

PTH is a metabolic active hormone primarily regulating calcium and phosphate homeostasis in a very tight and short term-manner. Parathyroid disorders in adult patients reflect a variety of different conditions related either to the parathyroid glands itself or to the effects of the secreted hormone. The clinical spectrum varies from the common disease primary hyperparathyroidism (PHPT) to the orphan conditions pseudohypoparathyroidism (Ps-HypoPT) and chronic hypoparathyroidism (HypoPT). The purpose of this review is to describe the consequences of disturbances in levels or action of PTH for cardiac function and cardiovascular risk in adult patients with these disorders. Most patients with PHPT achieve the diagnose by chance and have minor or no specific symptoms. Still, these patients with mild PHPT do possess cardiovascular (CV) morbidity, however so far not proven ameliorated by surgery in controlled trials. In severe cases, the CV risk is increased and with a potential reversibility by treatment. Patients with Ps-HypoPT have resistance to PTH action, but not necessarily total resistance in all tissues. So far, no clear CV morbidity or risk has been demonstrated, but there are several aspects of interest for further studies. Most patients with HypoPT do get their hormonal deficiency syndrome following neck surgery. These patients do experience multiple symptoms and do have an increased CV-risk before the primary surgery. Based on existing data, their CV mortality do not deviate from the expected when adjusting for the preexisting increased risk. Patients with nonsurgical (NS-) HypoPT do demonstrate increased CV-risk also associated with exposure time. Endocrine disorders with alterations in PTH function have major impact on the cardiovascular system of importance for morbidity and mortality, wherefore management of these specific diseases should be optimized currently, as new data become available, however also avoiding over-treating asymptomatic patients.