Introduction Causes of ↓ PTH release include accidental surgical excision (thyroidectomy) autoimmune destruction of parathyroid glands DiGeorge syndrome congenital absence of parathyroid glands hypomagnesemia ↓ functional adenylate cyclase leading to ↓ PTH activity Can also be caused by resistance of PTH pseudohypoparathyroidism renal tubules do not respond in presence of PTH aka Albright hereditary osteodystrophy AD inheritance Presentation Symptoms tetany (hypocalcemia) Physical exam Chvostek's sign contraction of facial muscles when tapped rapidly Trousseau's sign carpal spasm following occlusion of brachial artery with BP cuff findings unique to pseudohypoparathyroidism (Albright hereditary osteodystrophy) shortened 4th/5th digits Turners syndrome only involves 5th digit short stature Evaluation Serology hypocalcemia hyperphosphatemia Treatment Medical calcium + calcitriol (D3) supplemenation teriparatide recombinant PTH