Hypoparathyroidism is a disorder defined by decreased parathyroid hormone (PTH) production. Causes include surgical removal or damage during head and neck surgery and autoimmune destruction of the parathyroid glands. Acute clinical manifestations are mainly related to hypocalcemia and include muscle cramps that may progress to spasms, xerosis and brittle nails, numbness and tingling of the extremities or area around the mouth, and confusion or depression. Chronic hypoparathyroidism is associated with basal ganglia calcification, ocular disease, and skeletal and dental abnormalities.