In patients with kidney failure, long-term retention of acid and loss of calcium in the body after long-term dialysis can cause secondary hyperparathyroidism and stimulate parathyroid hyperplasia. The normal parathyroid glands are about half the size of a pea, but in patients with secondary hyperparathyroidism, parathyroid hyperplasia may increase to the size of a pea or even larger. In normal people, the parathyroid glands cannot be detected by ultrasound, but if the parathyroid glands are detected by ultrasound or CT, then enlargement should be considered. Patients with uremia should be tested regularly for parathyroid hormone (abbreviated as PTH) if they have symptoms such as generalized bone pain, stones, and shortening of height (commonly known as retreating man syndrome), which can decrease from 180 to 160 cm, and the normal level is between 0 and 20. I have seen one case where the PTH was as high as 6,000 units, and in general, patients with secondary hyperparathyroidism should consider surgery if they are between 600 and 1,800 units. The purpose of surgery is to improve the quality of life and to reduce bone pain and calcium loss. However, if too many are retained, the surgical effect is greatly reduced.