- Etiology/Pathophysiology
- Decreased production of Parathyroid Hormone (PTH) leads to ↓ serum Ca2+ and ↑ serum PO₄³⁻.
- Most common cause: Iatrogenic, secondary to neck surgery (e.g., total thyroidectomy) with accidental removal or devascularization of parathyroid glands.
- Other causes:
- Autoimmune destruction of parathyroid glands (often part of Autoimmune Polyglandular Syndrome Type 1).
- Genetic disorders: DiGeorge syndrome (22q11 deletion) causing parathyroid aplasia/hypoplasia.
- Infiltrative diseases (rare): Hemochromatosis, Wilson’s disease.
- Hypomagnesemia: Severe ↓ Mg2+ impairs PTH secretion and action.