In primary hyperparathyroidism, what electrolyte pattern is typical and what is a reasonable initial management approach?

• A. Hypercalcemia with possible hypophosphatemia; hydration, sometimes diuretics after rehydration, and consideration of parathyroidectomy; bisphosphonates to manage calcium.
• B. Hypocalcemia with hyperphosphatemia; start calcium supplementation.
• C. Hyperkalemia with metabolic acidosis; treat with bicarbonate.
• D. Normal calcium with elevated phosphate; observe

Answer: (A)

Elevated parathyroid hormone in primary hyperparathyroidism drives calcium upward and phosphate downward, so the typical electrolyte picture is hypercalcemia often with low or low-normal phosphate levels. The goal in the initial approach is to lower calcium and stabilize the patient while planning definitive treatment. Start with aggressive IV isotonic saline to correct volume depletion and promote calcium excretion; after hydration, loop diuretics can be considered to enhance calciuresis if needed, but avoid thiazide diuretics which raise calcium. Bisphosphonates can rapidly reduce serum calcium by inhibiting bone resorption, and calcitonin may provide a quicker, short-term decrease. Definitive management is surgical removal of the overactive parathyroid tissue. The other patterns—hypocalcemia with hyperphosphatemia, hyperkalemia with acidosis, or normal calcium with high phosphate—do not fit this condition.