title: Challenges in the differential diagnosis of hypercalcemia: A case of hypercalcemia with normal PTH level.
abstract: The hypercalcemias are a common and heterogeneous group of disorders, ranging from the occasional detection of a high level of serum calcium to a life-treating condition. In a patient presenting with hypercalcemia, a differential diagnosis can be established easily by measuring serum calcium and parathyroid hormone (PTH) concentrations. We describe the case of an 83-year-old man presenting with a severe symptomatic hypercalcemia with high-normal PTH level due to the coexistence of primary hyperparathyroidism and malignancy-associated hypercalcemia. The presence of two conditions producing hypercalcemia was revealed only during in-hospital stay and after the administration of an intravenous bisphosphonate, when the PTH concentration increased rapidly after bisphosphonate treatment with a decrease in serum calcium. The occurrence of two conditions producing hypercalcemia is a rare event in the literature, and should be considered in the presence of an abnormally high serum calcium level associated with normal or high-normal PTH, in order to establish a correct diagnosis and appropriate interventions.
authors.affiliation: Francesca Pellicciotti, Salvatore Foderaro, Alberto Ferrari, Giulio Pioli, Geriatric Unit, Arcispedale Santa Maria Nuova, Viale Risorgimento 80, 42123 Reggio Emilia, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Pellicciotti
authors.forename: Andrea
authors.initials: A
authors.lastname: Giusti
authors.forename: Maria Carolina
authors.initials: MC
authors.lastname: Gelli
authors.forename: Salvatore
authors.initials: S
authors.lastname: Foderaro
authors.forename: Alberto
authors.initials: A
authors.lastname: Ferrari
authors.forename: Giulio
authors.initials: G
authors.lastname: Pioli