Tertiary hyperparathyroidism is a condition that typically occurs in patients with chronic kidney disease, where the parathyroid glands become hyperactive due to prolonged stimulation from low calcium levels and high phosphate levels. One of the significant complications that can arise due to bone loss in tertiary hyperparathyroidism is osteitis fibrosa cystica.

This condition is characterized by the following:

1. Bone Resorption: Increased parathyroid hormone (PTH) levels lead to enhanced bone resorption, resulting in a loss of bone density and structural integrity.
2. Cyst Formation: The excessive resorption can lead to the formation of cyst-like spaces in the bone, which can weaken the bone and increase the risk of fractures.
3. Bone Pain and Deformities: Patients may experience bone pain and deformities due to the weakening of the skeletal structure.

Additionally, patients may also be at risk for other complications such as fractures, particularly in weight-bearing bones, and other forms of bone disease due to the imbalance in calcium and phosphate metabolism.

If you have further questions or need more detailed information, feel free to ask!