Final answer:
The risk of metastatic calcification increases when the product of serum calcium and phosphorus levels rises significantly due to conditions that disrupt the normal balance of these minerals, such as hyperparathyroidism.
Step-by-step explanation:
The risk of metastatic calcification in soft tissues, which involves the deposition of calcium salts outside of bones, can increase when there is an imbalance in serum calcium and phosphorus levels. Normally, the product of serum calcium and phosphorus (in mg/100 ml) is around 50 in children and may be even lower during rickets. Disorders like hyperparathyroidism lead to increased calcium levels (hypercalcemia) and may also cause higher phosphorus levels, which combined can precipitate this condition. The optimal ratio for calcium and phosphorus is approximately 1:1 (ranging from 1:2 to 2:1). When this ratio is disrupted and the product exceeds certain thresholds, it creates a conducive environment for metastatic calcification.
In the clinical context, the options provided (25, 55, 75, 95) represent these threshold values, with the correct answer reflecting the point at which the risk of calcification significantly increases. It is essential to monitor these levels in patients with disorders affecting calcium and phosphorus metabolism to prevent the development of calcified deposits in soft tissues.