The relationship between
osteoporosis and
magnesium (Mg) deficiency is still controversial. Here we report a case of an 82-year-old woman with a giant adenomatous
goiter and severe
osteoporosis with multiple vertebral fractures, whose
clinical course indicated that her
osteoporosis was probably due to Mg deficiency. She visited our hospital for treatments of
tetany. Laboratory data showed the existence of hypomagnesemia,
hypocalcemia,
hypokalemia,
vitamin D deficiency, and slightly elevated intact PTH.
Intravenous administration of Mg not only improved these
electrolyte abnormalities but also increased serum levels of intact PTH, bone formation markers,
1,25-dihydroxyvitamin D, as well as
bone resorption markers in the urine, and lowered urinary
phosphate reabsorption. Hypomagnesemia on admission seemed to arise from long-lasting poor food intake and
malnutrition, because it improved after the disappearance of
dysphagia with a
goiter resection. After the operation, BMD values at the lumbar spine and femoral neck obviously increased during 6 months of Mg supplementation without any specific
therapies for
osteoporosis. Mg deficiency in this case seemed to cause impaired secretion of PTH from the parathyroid and the refractoriness of bone and kidney to the
hormone, which led to the suppression of both bone remodeling and renal
vitamin D production. These processes were probably linked to her severe
osteoporosis, which was reversed by Mg supplementation.