Familial Hypocalciuric Hypercalcemia in Pregnancy: Diagnostic Pitfalls

Hypercalcemia Associated with Pregnancy and Lactation

Hypercalcemia during pregnancy is a risk for adverse maternal and fetal consequences. Although primary hyperparathyroidism is by far the most common etiology of hypercalcemia in pregnancy, an array of other etiologies of hypercalcemia associated with pregnancy and lactation have been described. Parathyroidectomy continues to be the preferred treatment for primary hyperparathyroidism. Medical management options are limited.

Familial states of primary hyperparathyroidism: an update

BACKGROUND

Familial primary hyperparathyroidism (PHPT) includes syndromic and non-syndromic disorders. The former are characterized by the occurrence of PHPT in association with extra-parathyroid manifestations and includes multiple endocrine neoplasia (MEN) types 1, 2, and 4 syndromes, and hyperparathyroidism-jaw tumor (HPT-JT). The latter consists of familial hypocalciuric hypercalcemia (FHH) types 1, 2 and 3, neonatal severe primary hyperparathyroidism (NSHPT), and familial isolated primary hyperparathyroidism (FIHP). The familial forms of PHPT show different levels of PHPT penetrance, developing earlier and with multiglandular involvement compared to sporadic counterpart. All these diseases exhibit Mendelian inheritance patterns, and for most of them, the genes responsible have been identified. DNA testing for predisposing mutations is helpful in index cases or in individuals with a high suspicion of the disease. Early recognition of hereditary disorders of PHPT is of great importance for the best clinical and surgical approach. Genetic testing is useful in routine clinical practice because it will also involve appropriate screening for extra-parathyroidal manifestations related to the syndrome as well as the identification of asymptomatic carriers of the mutation.

PURPOSE

The aim of the review is to discuss the current knowledge on the clinical and genetic profile of these disorders along with the importance of genetic testing in clinical practice.

Abnormal Calcium Levels are Associated With Worse Maternal and Fetal Outcomes; Results From an Exploratory Study

CONTEXT

Precise estimates of the incidence of hyper- and hypocalcemia in pregnancy are unknown. Abnormal calcium levels have been associated with unfavorable pregnancy-related outcomes.

OBJECTIVE

Determine frequency of hypercalcemia and hypocalcemia in pregnancy when tested and their associations with maternal and fetal outcomes.

DESIGN

Exploratory retrospective cohort study.

SETTING

Single tertiary care maternity unit.

PATIENTS

Pregnant women with expected delivery date between 2017 and 2019 and a second additional cohort of pregnant women with hypercalcemia between 2014 and 2016 and 2020 and 2021.

INTERVENTIONS

Observational.

MAIN OUTCOMES MEASURED

(1) Incidence of hyper- and hypocalcemia when calcium tested; (2) maternal outcomes: incidence of preterm delivery, emergency cesarean section, and blood loss during delivery; and (3) fetal outcomes: fetal loss (miscarriage/stillbirth), neonatal intensive care unit admission, and fetal birth weight (for term deliveries).

RESULTS

Total number of gestations and livebirths recorded were 33 118 and 20 969, respectively, with median [interquartile range] age of 30.1 [25.6-34.3] years. A total of 15.7% (n = 5197) of all gestations had albumin-adjusted calcium tested, and incidence of hypercalcemia and hypocalcemia when tested was 0.8% (n = 42) and 9.5% (n = 495), respectively. Both hypercalcemia (including additional cohort n = 89) and hypocalcemia were associated with increased incidence of preterm delivery (P < .001), emergency cesarean section (P < .001 and .019), blood loss (P < .001), and neonatal intensive care unit admission (P < .001). A total of 27% in the hypercalcemic group had an established diagnosis of primary hyperparathyroidism.

CONCLUSIONS

Abnormal calcium levels during pregnancy are common and associated with worse pregnancy-related outcomes, which raises the possible need for routine calcium testing. Prospective studies to confirm the incidence, etiology, and effects of abnormal calcium in pregnancy are recommended.

Expert consensus on multidisciplinary approach to the diagnosis and treatment of primary hyperparathyroidism in pregnancy in China

Primary hyperparathyroidism in pregnancy is a rare disease that can have detrimental effects on both maternal and fetal/neonatal outcomes. The physiological changes that occur during pregnancy can complicate the diagnosis, imaging examinations, and treatment of this disorder. To enhance our understanding and management of primary hyperparathyroidism in pregnancy, experts from various fields, including endocrinology, obstetrics, surgery, ultrasonography, nuclear medicine, pediatrics, nephrology, and general practice in China, collaborated to develop a consensus addressing the critical aspects of the diagnosis and treatment of primary hyperparathyroidism in pregnancy with a multidisciplinary team approach. This consensus provides valuable guidance for healthcare professionals in managing this condition, ultimately improving outcomes for both mothers and their babies.

Approach to the patient: Management of parathyroid diseases across pregnancy

Taking care of patients with parathyroid disorders during pregnancy requires consideration of the physiological fundamental changes in bone and mineral metabolism occurring in these women. Diagnostic and therapeutic procedures regarding primary hyperparathyroidism (PHPT) and hypoparathyroidism significantly differ from the non-pregnant population. PHPT should preferably be cured by parathyroidectomy before pregnancy as in women with hypercalcemic PHPT, maternal and fetal pregnancy complications seem to increase according to the degree of hypercalcemia. Parathyroidectomy, if needed during pregnancy, is preferentially performed in the second trimester. Conservative treatment is recommended for milder cases and is mainly restricted to hydration with only limited evidence regarding drug treatment. Women with hypoparathyroidism can be informed that there are no major concerns regarding disease associated infertility and that the risk of pregnancy complications is low if the disease is properly managed. Regular active surveillance is recommended as requirements for calcium and active vitamin D may change during the course of pregnancy in either direction, with an overall trend for rather reduced doses. Any woman suffering from parathyroid disorders during pregnancy requires further surveillance in the postpartum period and during lactation, as there is an increased risk of hypercalcemia after delivery. Newborns of mothers with parathyroid diseases should, depending on disease severity, be carefully monitored for calcium levels in the first days (to weeks) after delivery as intrauterine exposure to hyper- or hypocalcemia may impact their postnatal regulation of calcium metabolism.

Disorders of the Calcium Sensing Signaling Pathway: From Familial Hypocalciuric Hypercalcemia (FHH) to Life Threatening Conditions in Infancy

Familial hypocalciuric hypercalcemia (FHH) is a mostly benign condition of elevated calcium and PTH levels based on a hyposensitive calcium sensing receptor (CaSR) in FHH 1 or its downstream regulatory pathway in FHH2 and FHH3. In children, adolescents and young adults with FHH the main challenge is to distinguish the condition from primary hyperparathyroidism and thereby to avoid unnecessary treatments including parathyroidectomy. However, inheritance of FHH may result in neonatal hyperparathyroidism (NHPT) or neonatal severe hyperparathyroidism (NSHPT), conditions with high morbidity, and in the latter even high mortality. This review focuses on the genetic and pathophysiological framework that leads to the severe neonatal form, gives recommendations for counselling and summarizes treatment options.

European Expert Consensus on Practical Management of Specific Aspects of Parathyroid Disorders in Adults and in Pregnancy: Recommendations of the ESE Educational Program of Parathyroid Disorders

This European expert consensus statement provides recommendations for the diagnosis and management of primary hyperparathyroidism (PHPT), chronic hypoparathyroidism in adults (HypoPT), and parathyroid disorders in relation to pregnancy and lactation. Specified areas of interest and unmet needs identified by experts at the second ESE Educational Program of Parathyroid Disorders (PARAT) in 2019, were discussed during two virtual workshops in 2021, and subsequently developed by working groups with interest in the specified areas. PHPT is a common endocrine disease. However, its differential diagnosing to familial hypocalciuric hypercalcemia (FHH), the definition and clinical course of normocalcemic PHPT, and the optimal management of its recurrence after surgery represent areas of uncertainty requiring clarifications. HypoPT is an orphan disease characterized by low calcium concentrations due to insufficient PTH secretion, most often secondary to neck surgery. Prevention and prediction of surgical injury to the parathyroid glands are essential to limit the disease-related burden. Long-term treatment modalities including the place for PTH replacement therapy and the optimal biochemical monitoring and imaging surveillance for complications to treatment in chronic HypoPT, need to be refined. The physiological changes in calcium metabolism occurring during pregnancy and lactation modify the clinical presentation and management of parathyroid disorders in these periods of life. Modern interdisciplinary approaches to PHPT and HypoPT in pregnant and lactating women and their newborns children are proposed. The recommendations on clinical management presented here will serve as background for further educational material aimed for a broader clinical audience, and were developed with focus on endocrinologists in training.

Hypercalcemia in Pregnancy

Hypercalcemic disorders are rare in pregnant women and are usually due to primary hyperparathyroidism. Clinical manifestations of hypercalcemia are nonspecific and can be masked by the physiologic changes of pregnancy. Furthermore, routine antenatal screening does not include serum calcium measurement and a hypercalcemia diagnosis may therefore be delayed until term or even after delivery. Timely recognition and appropriate interventions are essential to decrease maternal and fetal complications. Conservative measures are appropriate in the presence of mild hypercalcemia. Parathyroidectomy remains the mainstay of treatment for primary hyperparathyroidism with significant hypercalcemia not responding to conservative measures.

Primary Hyperparathyroidism in Pregnancy: Literature Review of the Diagnosis and Management

Background: Parathyroid disease is uncommon in pregnancy. During pregnancy, multiple changes occur in the calcium regulating hormones which may make the diagnosis of primary hyperparathyroidism more challenging. Close monitoring of serum calcium during pregnancy is necessary in order to optimize maternal and fetal outcomes. In this review, we will describe the diagnosis and management of primary hyperparathyroidism during pregnancy. Methods: We searched MEDLINE, CINAHL, EMBASE and Google scholar bases from 1 January 1990 to 31 December 2020. Case reports, case series, book chapters and clinical guidelines were included in this review. Conclusions: Medical management options for primary hyperparathyroidism during pregnancy are severely limited due to inadequate safety data with the various potential therapies available, and surgery is advised during the 2nd trimester of pregnancy in the presence of severe hypercalcemia (calcium adjusted for albumin greater than 3.0 mmol/L (12.0 mg/dL)). Hypercalcemia should be avoided during pregnancy in order to minimize maternal and fetal complications.

Primary hyperparathyroidism presenting as a brown tumor with hypercalcemia crisis in a second-trimester pregnant woman: A case report

INTRODUCTION

Primary hyperparathyroidism (PHPT) in pregnancy is rare and unrecognized because the maternal physiological adaptations blurs the symptoms. There is no standard treatment strategy for maternal PHPT. Early diagnosis and interventions can prevent catastrophic consequences to the mother and fetus.

PATIENT CONCERNS

A 31-year-old Chinese woman was admitted, due to a lump on the left lower leg for 4 months. The patient complained of mild pain in the left lower leg following exercise that could be relieved after a short rest. The patient was at 18 weeks of gestation, and the growth of the fetus was normal. The patient has a 3-year history of hypercalcemia and a 2-year history of nephrolithiasis. No family history of hypercalcemia and endocrine tumors were present.

DIAGNOSIS

Laboratory tests demonstrated high serum calcium level of 3.84 mmol/L, parathyroid hormone 1393 pg/mL, alkaline phosphatase 488 μ/L. Ultrasound showed a 22.4 mm × 7.8 mm solid nodule in the left lower lobe of the thyroid gland. Based on these findings, the patient was diagnosed with PHPT.

INTERVENTIONS

The patient accepted continuous renal replacement to reduce ironized calcium level. Parathyroidectomy was performed at the 19th week of gestation. Threatened abortion occurred 2 days after the surgery, and magnesium sulfate was used to prevent the abortion. Calcium gluconate, calcium carbonate and vitamin D3 were used to treat the hypocalcemia that occurred 5 days after the surgery.

OUTCOMES

Pathology examination demonstrated the parathyroid adenoma. Abortion was prevented using magnesium sulfate and hypocalcemia was cured with calcium gluconate, calcium carbonate and vitamin D3. At 38-week of gestation, the patient (ionized calcium level: 2.16 mmol/L) delivered a healthy female baby weighing 2700 g with 10/10 Apgar. Till now, both the mother and infant showed no complications.

CONCLUSION

Maternal PHPT is rare and challenging to diagnose, causing life-threatening complications to mother and fetus. Any decision regarding surgery for a pregnant woman with primary hyperparathyroidism is more complex than in men or nonpregnant women. The decision should be made based on the severity of hypercalcemia and symptoms.

Parathyroid Disease in Pregnancy and Lactation: A Narrative Review of the Literature

Pregnancy and lactation are characterized by sophisticated adaptations of calcium homeostasis, aiming to meet fetal, neonatal, and maternal calcium requirements. Pregnancy is primarily characterized by an enhancement of intestinal calcium absorption, whereas during lactation additional calcium is obtained through resorption from the maternal skeleton, a process which leads to bone loss but is reversible following weaning. These maternal adaptations during pregnancy and lactation may influence or confound the presentation, diagnosis, and management of parathyroid disorders such as primary hyperparathyroidism or hypoparathyroidism. Parathyroid diseases are uncommon in these settings but can be severe when they occur and may affect both maternal and fetal health. This review aims to delineate the changes in calcium physiology that occur with pregnancy and lactation, describe the disorders of calcium and parathyroid physiology that can occur, and outline treatment strategies for these diseases in the above settings.

Hypercalcemia during pregnancy: management and outcomes for mother and child

Diagnosing and treating hypercalcemia during pregnancy can be challenging due to both the physiological changes in calcium homeostasis and the underlying cause for the hypercalcemia. During pregnancy and lactation there is increased mobilization of calcium in the mother to meet the fetus' calcium requirements. Here we discuss the diagnostic challenges, management, and patient perspective of hypercalcemia during pregnancy in two particular cases and in other rare conditions causing hypercalcemia.

Case Report: Severe Neonatal Course in Paternally Derived Familial Hypocalciuric Hypercalcemia

Familial hypocalciuric hypercalcemia (FHH, [OMIM #145980]) is recognized as a benign endocrine condition affecting PTH and calcium levels due to heterozygous inactivating mutations in the calcium sensing receptor (CaSR). The condition is often un- or misdiagnosed but may have a prevalence as high as 74 in 100.000. Here, the neonatal courses of two brothers with paternally inherited FHH (CaSR c.554G>A; p.(Arg185Gln)) are described. The older brother was born preterm at 25 weeks gestation with hypercalcemia and hyperparathyroidism. The younger brother, born full-term, had severe hyperparathyroidism, muscular hypotonia, thrombocytopenia, failure to thrive and multiple metaphyseal fractures. Treatment with cinacalcet was initiated, which resulted in subsequent reduction of PTH levels and prompt clinical improvement. While it is known that homozygous mutations in CaSR may lead to life-threatening forms of neonatal severe hyperparathyroidism (NSHPT), few reports have described a severe clinical course in neonates with FHH due to heterozygous mutations. However, based on the pathophysiological framework, in de novo or paternally transmitted FHH the differing calcium needs of mother and fetus can be expected to induce fetal hyperparathyroidism and may result in severe perinatal complications as described in this report. In summary, FHH is a mostly benign condition, but transient neonatal hyperparathyroidism may occur in affected neonates if the mutation is paternally inherited. If severe, the condition can be treated successfully with cinacalcet. Patients with FHH should be informed about the risk of neonatal disease manifestation in order to monitor pregnancies and neonates.