Thyroid & Adrenal
Tertiary hyperparathyroidism is charact-erized by
|A||Autonomous chief cell hyperplasia|
|B||Primary and secondary exaggerated|
|D||Thyroid surgery complication|
a. Tertiary HPT occurs in two settings.:
i. Patients with secondary HPT in which the parathyroid glands become autonomous and hypercalcemia develops.
ii. The second was first recognized by St. Goar, who described how secondary HPT can persist even after patients underwent renal transplantation; he postulated that the parathyroids became autonomous.
b. Hypercalcemia can persist in 8.5% to 53% of transplant recipients.
c. Transplant patients may have additional factors that can contribute to persistent tertiary HPT; glucocorticoids, cyclosporine, thiazide diuretics, and alterations in the glomerular filtration rate as a result of tubular injury or rejection episodes can influence parathyroid function and bone response.
d. Accordingly, patients with severe secondary HPT should not undergo renal transplantation until their secondary HPT has been treated.
e. It is known that severe hypercalcemia may adversely affect renal graft function. Therefore, calcium levels higher than 11 mg/dL may need to be addressed more aggressively.
f. Surgical treatment of tertiary HPT after renal transplantation is not common and is reserved for patients without resolution of symptoms, patients with hormonal and chemical abnormalities such as elevated or increasing iPTH levels and an increase in serum calcium to greater than 12.0 mg/dL that persists more than 1 year after transplantation, and patients with acute hypercalcemia (calcium level >12.5 mg/dL) in the immediate post-transplant period.