Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Thier 1101, 50 Blossom St, Boston, MA, 02114, USA.
Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Thier 1101, 50 Blossom St, Boston, MA, 02114, USA.
Best Pract Res Clin Endocrinol Metab. 2018 Oct;32(5):639-656. doi: 10.1016/j.beem.2018.05.006. Epub 2018 May 28.
Calcium is vital for life, and extracellular calcium concentrations must constantly be maintained within a precise concentration range. Low serum calcium (hypocalcemia) occurs in conjunction with multiple disorders and can be life-threatening if severe. Symptoms of acute hypocalcemia include neuromuscular irritability, tetany, and seizures, which are rapidly resolved with intravenous administration of calcium gluconate. However, disorders that lead to chronic hypocalcemia often have more subtle manifestations. Hypoparathyroidism, characterized by impaired secretion of parathyroid hormone (PTH), a key regulatory hormone for maintaining calcium homeostasis, is a classic cause of chronic hypocalcemia. Disorders that disrupt the metabolism of vitamin D can also lead to chronic hypocalcemia, as vitamin D is responsible for increasing the gut absorption of dietary calcium. Treatment and management options for chronic hypocalcemia vary depending on the underlying disorder. For example, in patients with hypoparathyroidism, calcium and vitamin D supplementation must be carefully titrated to avoid symptoms of hypocalcemia while keeping serum calcium in the low-normal range to minimize hypercalciuria, which can lead to renal dysfunction. Management of chronic hypocalcemia requires knowledge of the factors that influence the complex regulatory axes of calcium homeostasis in a given disorder. This chapter discusses common and rare disorders of hypocalcemia, symptoms and workup, and management options including replacement of PTH in hypoparathyroidism.
钙对生命至关重要，细胞外钙浓度必须维持在精确的浓度范围内。低血清钙（低钙血症）与多种疾病有关，如果严重，可能危及生命。急性低钙血症的症状包括神经肌肉兴奋性、抽搐和癫痫发作，这些症状可通过静脉注射葡萄糖酸钙迅速缓解。然而，导致慢性低钙血症的疾病通常表现得更为微妙。甲状旁腺功能减退症的特征是甲状旁腺激素（PTH）分泌受损，PTH 是维持钙稳态的关键调节激素，是慢性低钙血症的经典病因。维生素 D 代谢紊乱也可导致慢性低钙血症，因为维生素 D 负责增加肠道对膳食钙的吸收。慢性低钙血症的治疗和管理方案因潜在疾病而异。例如，在甲状旁腺功能减退症患者中，钙和维生素 D 的补充必须仔细滴定，以避免低钙血症的症状，同时将血清钙保持在低正常范围内，以最小化可导致肾功能障碍的高钙尿症。慢性低钙血症的管理需要了解影响特定疾病中钙稳态复杂调节轴的因素。本章讨论了常见和罕见的低钙血症疾病、症状和检查，以及管理选择，包括甲状旁腺功能减退症中 PTH 的替代治疗。
