ASAP Live - Bone & Parathyroid Disorders-PowerPoint

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A 60-year-old woman with a history of nephrolithiasis is being evaluated for hypercalcemia. She has been taking vitamin D supplements and has a low-normal parathyroid hormone level. She has normal blood tests for calcium, phosphorus, creatinine, and albumin. Her bone mineral density shows low T-scores in the femur neck and lumbar spine. The most likely cause of her hypercalcemia is 24-hydroxylase enzyme deficiency caused by a CYP24A1 mutation. Treatment options for her hypercalcemia include intravenous bisphosphonates, ketoconazole, glucocorticoid therapy, and parathyroidectomy. Reduction in calcium intake, avoidance of excess vitamin D sources, and appropriate fluid intake are initial management strategies. Intravenous bisphosphonates and other medications like denosumab and calcitonin are used for the management of bone resorption. Glucocorticoids are used for the treatment of granulomatous diseases. Parathyroidectomy is recommended for patients with primary hyperparathyroidism. The patient's genetic mutation affects the metabolism of vitamin D, causing hypercalcemia. The diagnosis of the cause of hypercalcemia is important for appropriate management. <br /><br />A 76-year-old woman comes to the clinic with a recent diagnosis of osteoporosis. She has lost height and has a family history of hip fractures. She eats a healthy diet and leads an active lifestyle. Her bone mineral density shows low T-scores in the lumbar spine, femoral neck, and total hip. The most appropriate medication for her osteoporosis is zoledronic acid. Other medications like alendronate, raloxifene, and romosozumab are also used for the treatment of osteoporosis. The patient's risk factors for osteoporosis include her age, parental history of hip fracture, and history of an untreated premature menopause. Zoledronic acid has been shown to reduce fractures and all-cause mortality in postmenopausal women with osteoporosis. It is important to consider the patient's individual risk factors and select the appropriate medication for treatment. <br /><br />A 30-year-old man is being evaluated for hypophosphatemia. He reports longstanding fatigue, muscle weakness, and bone and joint pain. His physical examination reveals mild bowing of his lower extremities. Laboratory tests show low phosphorus, normal calcium and creatinine levels, and high parathyroid hormone level. The most likely diagnosis for the patient's hypophosphatemia is X-linked hypophosphatemia (XLH), which is caused by inactivating pathogenic variants in the PHEX gene. XLH is characterized by increased production of fibroblast growth factor 23 (FGF-23), leading to hypophosphatemia and low-normal or inappropriately normal 1,25-dihydroxyvitamin D levels. Treatment options for XLH include phosphate and calcitriol supplementation. Diagnosis of XLH is important for appropriate management of the condition. <br /><br />A 72-year-old man who underwent liver-kidney transplantation 10 years ago is being evaluated for osteopenia. He is taking immunosuppressive medications and has stable kidney and liver function. His bone mineral density shows low T-scores in the hip and lumbar spine. Based on US guidelines, the most appropriate recommendation for this patient is treatment with an oral bisphosphonate, lifestyle modifications, and calcium supplementation. Bisphosphonates have been shown to reduce fractures in patients with glucocorticoid-induced osteoporosis. Other treatment options include teriparatide, denosumab, and raloxifene. It is important to consider the patient's individual risk factors and select the appropriate treatment for osteoporosis. <br /><br />A 57-year-old man is evaluated for osteoporosis. He has no history of fractures, kidney stones, or glucocorticoid use. His dual-energy X-ray absorptiometry (DXA) scan shows low T-scores at multiple bone sites. Laboratory tests show normal calcium, phosphorus, creatinine, and parathyroid hormone levels. The most appropriate next step in management is to measure serum magnesium. Hypomagnesemia can cause refractory hypocalcemia and can be associated with symptoms such as paresthesias and muscle cramping. The patient's symptoms, physical examination findings, and negative history for common causes of osteoporosis suggest hypomagnesemia as the underlying cause of his refractory hypocalcemia. Determining the magnesium level is important for appropriate management. <br /><br />A 32-year-old woman is admitted to the hospital for hypocalcemia. She reports paresthesias and muscle cramping in her extremities. She had a recent gastrointestinal illness with nausea, vomiting, and diarrhea. Laboratory tests show low calcium, normal phosphorus, and low or inappropriately normal parathyroid hormone levels. The most appropriate next step in evaluation is to measure serum magnesium. Hypomagnesemia can cause refractory hypocalcemia, and patients with gastrointestinal illness and volume depletion are at risk for magnesium deficiency. Other causes of hypocalcemia, such as primary hypoparathyroidism, can be considered if hypomagnesemia is ruled out. Measurement of magnesium levels is an important step in identifying the underlying cause of hypocalcemia.
Keywords
hypercalcemia
vitamin D supplements
parathyroid hormone
bone mineral density
CYP24A1 mutation
osteoporosis
zoledronic acid
hypophosphatemia
XLH
serum magnesium