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Hypercalcemia and hyperparathyroidism
Published in Nadia Barghouthi, Jessica Perini, Endocrine Diseases in Pregnancy and the Postpartum Period, 2021
Most cases of PHPT are sporadic, presenting with a single parathyroid adenoma. However, hereditary syndromes such as multiple endocrine neoplasia, familial hypocalciuric hypercalcemia (FHH), and jaw-tumor syndrome should be kept in mind. Though hereditary forms of PHPT usually correspond with multiglandular diseases, they may initially present with PHPT alone.
Endocrine diseases and pregnancy
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Hypercalcemic disorders other than PHP are very rarely encountered in pregnancy. Familial hypocalciuric hypercalcemia, also known as familial benign hypercalcemia, was first characterized in the early 1970s as an autosomal dominant genetic disorder notable for mild to moderate hypercalcemia accompanied by extremely low fractional excretion of calcium (ratio of calcium to creatinine clearance <0.01). It is now known to result from a mutation of the calcium-sensing receptor in both parathyroid and renal tubular tissues. There are no maternal consequences of this disorder, but neonatal hypocalcemic tetany can occur, with management similar as in maternal hyperparathyroidism (85). It is important to recognize the disorder for what it is so that maternal parathyroidectomy is not attempted. Malignancy-related hypercalcemia has only been reported in two pregnant patients, with maternal demise occurring within 4months postpartum in both cases (94,95).
Physiology of the Thyroid and Parathyroid Glands
Published in John C Watkinson, Raymond W Clarke, Louise Jayne Clark, Adam J Donne, R James A England, Hisham M Mehanna, Gerald William McGarry, Sean Carrie, Basic Sciences Endocrine Surgery Rhinology, 2018
The calcium-sensing receptor (CaSR) is a class C G-protein coupled receptor which senses extracellular levels of calcium ions. In the parathyroid gland CaSR controls calcium homeostasis by regulating the release of PTH. Mutations that inactivate the CaSR gene cause familial hypocalciuric hypercalcemia (FHH), which generally is asymptomatic and does not require treatment. Therefore, it is important to distinguish this benign disorder from PHPT. Not all patients with PHPT require surgical treatment, and there is consensus that asymptomatic patients with adjusted calcium concentrations below 3 mmol/L and absence of end-organ damage related to longer-term PTH excess such as osteoporosis can be safely observed. Calcimimetics are a class of drugs with calcium-sensing receptor agonist properties that act directly on the parathyroid gland and decrease PTH release and serum calcium levels, and may also beneficially influence parathyroid tumour growth. Calcimimetics can be useful in patients with PHPT who are not eligible for surgical intervention.
An unusual case of severe hypercalcemia: as dehydrated as a bone
Published in Journal of Community Hospital Internal Medicine Perspectives, 2021
Roshan Acharya, Dylan M Winters, Cameron Rowe, Nathan Buckley, Smita Kafle, Bhaskar Chhetri
Using PubMed.gov with NCBI search terms of, ‘severe hypercalcemia’ with parameters set for full text, and dating from 2010 to 2020, 1029 results were generated. To emphasize the rarity of our case, of the first five results generated, one discusses vitamin D intoxication, one discussed inherited familial hypocalciuric hypercalcemia, and the other three discuss malignancy as the culprit. None of the first 50 results was due to dehydration as a primary culprit. There was mention of acute kidney injury and chronic kidney disease leading to elevated calcium levels; however, there were no reported cases of dehydration being the primary etiology. In a review of the literature, dehydration was not found to be associated with being the primary etiology in causing hypercalcemia [7–11]. We report a case of a 60-year-old female with a serum calcium level of 18 mg/dL (corrected for albumin was 19 mg/dL) due to dehydration.
Hypercalcemic crisis in third trimenon: evaluating the optimal treatment strategy
Published in Gynecological Endocrinology, 2018
Julie Refardt, Patricia Farina, Irene Hoesli, Christian Meier
PHPT is the most common cause of hypercalcemia during pregnancy [5,10] and has been described in several case reports and reviews of the literature. However, it is essential to rule out other causes of hypercalcemia, as this determines the further management. The most important differential diagnosis to an elevated PTH with only mild hypercalcemia is the benign familial hypocalciuric hypercalcemia [11], an autosomal dominant condition caused by a loss-of-function mutation in the calcium-sensing receptor gene (CASR) requiring no further interventions. In patients with low PTH-levels, secondary causes of hypercalcemia due to hyperthyroidism, vitamin D-intoxication, granulomatous disease and malignancy must be considered [6]. In case of suspected malignancy, parathyroid hormone-related peptide PTHrP should be measured [12]. PTHrP-related hypercalcemia is mostly caused by solid organ malignancy (e.g. lung, ovarian and renal cell carcinoma) but some cases have also been described of placental origin during pregnancy [13–15].
Pharmacoperone drugs: targeting misfolded proteins causing lysosomal storage-, ion channels-, and G protein-coupled receptors-associated conformational disorders
Published in Expert Review of Clinical Pharmacology, 2018
Zhi-Shuai Hou, Alfredo Ulloa-Aguirre, Ya-Xiong Tao
Mutations in the calcium-sensing receptor (CaSR) cause calcium-handling diseases [77,78]. It has been shown that allosteric agonists, such as NPS R-568, may stabilize CaSR mutants. NPS R-568 is a cotranslational stabilizer acting at a conformational checkpoint during CaSR biosynthesis [6,77]. A number of CaSR Class II (see below) loss-of-function mutants leading to familial hypocalciuric hypercalcemia and neonatal hyperparathyroidism can be stabilized and rescued by NPS R-568 [79]. Additionally, some gain-of-function CaSR mutants resistant to ERAD may respond to the negative allosteric modulator NPS 2143 which promotes their degradation [80]. Allosteric compounds have also been experimentally tested for rescuing ability of misfolded gonadotropin receptors. In the case of the misfolded A189V human FSHR, exposure of COS-7 cells to the thienopyr(im)idine Org 41841 led to almost a twofold increase in PM expression of the mutant receptor and agonist-stimulated cAMP production [81], whereas in the case of the LH/CGR, Org 42599 led to rescue of PM expression of the A593P and S616Y misfolded mutants [82].