Calcium and Phosphate Disorders Exam Prep 2026 – Complete Practice Test

Iatrogenic loss or damage to the parathyroid glands during thyroid or neck surgery is the most common cause of primary hypoparathyroidism. The parathyroids are tiny and lie right next to the thyroid, so during thyroidectomy or other neck procedures they can be accidentally removed or their blood supply disrupted, leading to insufficient PTH production and hypocalcemia. Autoimmune or genetic causes exist but are far less common. Vitamin D deficiency causes hypocalcemia through a different mechanism (often with inappropriately high PTH, i.e., secondary hypoparathyroidism rather than primary).