Acceleration of Preexisting Aortic Stenosis After Teriparatide Initiation.

Background/Objective: Teriparatide, an osteoanabolic agent similar to parathyroid hormone in properties, is used to manage severe osteoporosis. Aortic valve stenosis is a common valve condition observed in the elderly. Its natural history includes gradual progression toward severity. We present a case of a patient who had rapidly progressive aortic stenosis after teriparatide initiation. Case Report: An 84-year-old woman who was diagnosed with osteoporosis was treated with oral bisphosphonates. When she had spinal compression fractures, she was found to have primary hyperparathyroidism. She underwent parathyroidectomy and was treated with denosumab infusions every 6 months. However, after she experienced bilateral atypical femoral fractures, she was switched to teriparatide daily injections. Her laboratory test results showed a calcium level of 10 mg/dL (reference range, 8.5-10.2 mg/dL), 25-hydroxyvitamin D level of 38.2 ng/mL (reference range, 31.0-80.0 ng/mL), and phosphorus level of 3.3 mg/dL (reference, range, 2.7-4.8 mg/dL). On reviewing echocardiograms before and after teriparatide initiation, we found a rapid progression of her aortic stenosis from moderate to severe based on the mean gradients (23 to 40 mm Hg) and peak velocities (3.09 to 4 m/s), over a span of 10 months. She eventually required valve replacement. Discussion: Natural progression of mild to severe aortic stenosis typically occurs at the rate of 3 to 7 mm Hg per year over several years. Chronic exposure of human valvular endothelial cells to parathyroid hormone can trigger endothelial dysfunction and valvular calcification. Conclusion: In patients with preexisting aortic stenosis, coordination of care with cardiology and echocardiographic monitoring while on therapy may be considered.

Hypercalcemia and vitamin A: A vitamin to keep in mind.

Vitamin A, like many things in life, should be consumed in appropriate amounts. Excessive intake of preformed vitamin A, such as that found in supplements and animal sources (animal liver, fish liver oil, dairy, and eggs), is associated with multisystem effects that can include bone resorption and hypercalcemia. Hence, vitamin A toxicity should be explored in unexplained cases of parathyroid hormone-independent hypercalcemia. Serum retinol levels can be helpful in the diagnosis, but the results must be interpreted with caution since they do not always reflect total body levels. Treatment involves supportive care and withdrawal of vitamin A sources, especially preformed ones. Given the long half-life of retinol, normalization of serum levels can take several months.