Causes of hypocalcemic crisis
Hypocalcemic crisis may be a consequence of hypothyroidism of parathyroid glands in idiopathic hypoparathyroidism or consequence of impaired parathyroid gland development (isolated agenesis or paresis of the parathyroid gland, Di Gheorghe syndrome). Surgical operations, radioiodine therapy of thyroid gland diseases, malignant or granulomatous diseases and degenerative processes of parathyroid glands also have a significant significance. This complication is accompanied by an autoimmune lesion of parathyroid glands, observed with hemochromatosis, thalassemia, Wilson's disease. The cause may be a lack of secretion of parathyroid hormone, and a deficiency of the calcium-sensitive receptor gene or hypomagnesemia. In newborns, hypocalcemia is idiopathic or mediated by maternal hyperparathyroidism, diabetes mellitus, asphyxiation and prematurity.
Hypocalcemia sometimes occurs in the case of hypersecretion of the parathyroid hormone: if resistance develops to it or the secretion of biologically inactive parathyroid hormone occurs. The causes of hypocalcemia may also be conditions after treatment of Paget's disease and after treatment of diffuse toxic goiter, successful rickets therapy, metastases of osteoblastic tumors (breast and prostate cancer), vitamin D deficiency (violation of 25-hydroxylation, l-alpha hydroxylation, enterohepatic regulation, alimentary deficiency, lack of ultraviolet radiation). Hypocalcemia also accompanies such diseases as malabsorption, steatorrhea, vomiting and diarrhea, short bowel syndrome, acute pancreatitis, alcoholism, chronic renal insufficiency.
In addition, hypocalcemia is of iatrogenic nature: with the introduction of phosphates (or as a consequence of their excess in food), ethylenediaminetetraacetic acid (EDTA), thiazide diuretics, the use of actinomycin, neomycin, laxatives, phenobarbital and other anticonvulsants, inhibitors of bone resorption (calcitonin, bisphosphonates), with massive transfusion of citrated blood, operations in conditions of extracorporeal circulation.
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