Tertiary hyperparathyroidism (tHPT)

Summary:
Tertiary hyperparathyroidism (tHPT) occurs when parathyroid glands become autonomously overactive after prolonged secondary hyperparathyroidism, producing excessive PTH even when calcium levels normalize. Commonly linked to chronic kidney disease, symptoms resemble primary hyperparathyroidism. Treatment is typically surgical.

Details:
Tertiary hyperparathyroidism develops after chronic overstimulation of the parathyroid glands, causing them to function independently.

Causes:

  • Usually follows prolonged secondary hyperparathyroidism, particularly in CKD patients.

Symptoms:

  • Bone Pain and Osteoporosis.
  • Kidney Stones.
  • Muscle Weakness.
  • Fatigue and Weakness.
  • Gastrointestinal Symptoms: Nausea, vomiting.
  • Psychological Changes: Depression, irritability.

Diagnosis:

  • Elevated calcium and significantly increased PTH levels.
  • Often a history of secondary hyperparathyroidism.

Treatment:

  • Surgery: Removal of enlarged glands (parathyroidectomy) is usually necessary.
  • Medications: In less severe cases, vitamin D supplementation may help suppress PTH.

Medications for Hyperparathyroidism

Key Medications:

  1. Calcimimetics (e.g., Cinacalcet):
    • Increases calcium sensitivity of the parathyroid glands, reducing PTH secretion.
    • Used for primary and tertiary hyperparathyroidism, especially in non-surgical cases.
  2. Phosphate Binders:
    • Bind intestinal phosphate to lower blood phosphate levels.
    • Common in secondary hyperparathyroidism due to CKD (e.g., sevelamer, lanthanum carbonate).
  3. Vitamin D Analogs (e.g., Calcitriol, Paricalcitol):
    • Increase calcium absorption and suppress PTH production.
    • Used in secondary hyperparathyroidism or vitamin D deficiency.
  4. Calcium Supplements:
    • Elevate blood calcium levels, reducing PTH secretion.
    • Used with vitamin D therapy.
  5. Bisphosphonates:
    • Reduce bone resorption to manage hypercalcemia and prevent fractures.
    • Particularly useful in primary hyperparathyroidism.
  6. Denosumab:
    • A monoclonal antibody that inhibits bone resorption.
    • Alternative to bisphosphonates, especially in patients with kidney dysfunction.