Patients with PTH dependent hypercalcemia and patients with evidence of granulomatous disease were excluded as were patients with hematologic malignancies.
We report a case that presented with asymptomatic, familial hypercalcemia but low PTH and normal (non-low) urinary calcium excretion found to be secondary to a novel pathogenic inactivating mutation of the CaSR gene.
Familial hypocalciuric hypercalcemia is an autosomal dominant genetic disorder characterized by hypercalcemia associated with inappropriate hypocalciuria and normal parathyroid hormone levels.
We identified 3,200 patients with hypercalcemia (serum calcium >10.5 mg/dL) who had parathyroid hormone (PTH) levels evaluated at our institution from 2011 to 2016.
Given the patient's history of long-term dialysis, bone pain, high levels of intact parathyroid hormone(i-PTH) and hypercalcemia, we performed ultrasonography which showed solid nodules in the bilateral parathyroid glands.
Algorithms for diagnosis of PTH related hypercalcaemia require assessment of a 24-h urinary calcium and creatinine excretion to calculate calcium/creatinine clearance ratio and radiological investigations including ultrasound scan and <sup>99m</sup>Tc-sestamibi-SPECT/CT.
We collected data on patient age, gender, calcium levels, parathyroid hormone (PTH) levels, and medications/comorbidities known to cause hypercalcemia.
A low PTH level suggests non-parathyroid hypercalcemia due to a genetic defect in patients with no evidence of other conditions associated with hypercalcemia and low PTH levels and in those whose calcitriol levels are elevated or normal (instead of depressed as expected when PTH is elevated).
Those psychiatric complications are currently attributed to hypercalcemia with very little evidence; however, with the discovery of the parathyroid hormone 2 receptor (PTH2R) in the brain which can be activated by PTH, PTH2R might indicate a direct effect of PTH.
Primary hyperparathyroidism (pHPT) is the third most common endocrine disease and is characterized by hypercalcaemia and elevated or inappropriately 'normal' levels of the parathyroid hormone (PTH).
Hypercalcemia is generally due to the secretion of parathyroid hormone (PTH)-related peptide (PTHrP) by a wide variety of nonmetastatic solid tumors, including squamous cell tumors but also hematologic tumors.
Common features of this autosomal recessive condition included hypercalcemia with hypercalciuria, suppressed PTH and a high 25-OH-D<sub>3</sub>:24,25-(OH)<sub>2</sub>D<sub>3</sub> ratio.
Parathyroidectomy (PTX), surgical resection of parathyroid glands, is usually performed in cases of persistent serum levels of PTH above 1000 pg/mL associated with hypercalcemia or when hyperparathyroidism is refractory to conservative therapy.
Biological studies were remarkable for PTH-independent severe hypercalcemia with low 25-hydroxyvitamin D and a paradoxically elevated 1,25-dihydroxyvitamin D. Early bronchoalveolar lavage allowed for PCP diagnosis and targeted treatment.
Hypercalcaemia resulting from hypoadrenalism secondary to adrenal histoplasmosis is rare and should be suspected whenever evaluating a patient with PTH-independent hypercalcaemia.
As the frequency of PTH 1-34 injections increased, the total daily dose required to normalize calcium homeostasis decreased and episodes of hypercalcemia and hypercalciuria diminished, producing a more physiologic biochemical profile.