Final answer:
The first step in managing a patient with symptoms of hypercalcemia and skin tenting indicating dehydration is to rehydrate the patient with intravenous fluids, typically normal saline.
Step-by-step explanation:
The question refers to a patient presenting with symptoms of hypercalcemia, which are classically described as "stones, bones, groans, and psychic overtones," with the addition of physical examination (PEx) finding of skin tenting, which suggests dehydration. The first step in management of hypercalcemia, especially in a dehydrated patient, is usually rehydration with intravenous (IV) fluids, typically using normal saline. This initial management helps to restore volume status and improves renal calcium excretion. Moreover, addressing the underlying cause of the hypercalcemia will be crucial, but rehydration remains the immediate initial step.