Overview

Several different types:

• Primary Hyperparathyroidism (pHPT).
  • Elevated Calcium with high PTH, normal or low Phosphorous.
    • Treated surgically with a parathyroidectomy.
• Secondary (sHPT)
  • Normal or low Calcium, with elevated PTH and normal phosphorous.
  • PTH levels elevated due to chronic hypocalcemia (low calcium).
    • Vit D deficiency –impaired intestinal absorption of calcium.
    • Gastric bypass surgery or celiac disease – compromised absorption of calcium and Vit D in the intestines.
    • Chronic kidney failure – directly losing calcium into the urine, indirectly decreased activated form of Vit D 1,25 causing less intestinal absorption of calcium.
    • Renal leak – loss of calcium into urine without overt kidney failure.
      • Whatever the reason, the parathyroid glands appropriately compensate for low calcium with higher levels of PTH.
        • Appropriate ‘teeter totter’ response.
  • Treatment is medical (addressing the underlying cause) and can return PTH levels to the normal range (surgery is not indicated).
    • Exception is with chronic kidney disease causing Kidney Related Hyperparathyroidism.
    • Therefore, the distinction between primary and secondary hyperparathyroidism is very important given the differences in treatments, surgery vs medical.
• Tertiary (tHPT)
  • Elevated Calcium, PTH, and phosphorous levels
  • Occurs despite return of normal kidney function following cure of chronic kidney disease (e.g., kidney transplant).
    • Parathyroid glands that have been chronically compensating for low calcium levels due to kidney failure, will continue to produce large amounts of PTH autonomously despite return of normal calcium levels (loss of ‘teeter totter’ effect).
    • tHPT is treated surgically with parathyroidectomy.
  • The term ‘Kidney Related Hyperparathyroidism’ can refer to both chronic kidney disease causing sHPT and tHPT.