Hypophosphatemia is a metabolic derangement characterized by an abnormally low phosphate level in the blood serum. Rickets in children occurs due to low phosphate serum levels, while Osteomalacia is due to phosphorus deficit in adults 1. Osteoporosis may be brought on by an imbalance in the body’s phosphorus and calcium levels in bone metabolism. If the body does not have enough calcium in the blood, metabolic derangement called hypocalcemia develops. Over time, cataracts, dental changes, and other abnormalities may develop due to hypocalcemia. Nails become brittle, hair grows slowly, and the skin becomes delicate and thin due to a lack of calcium. Muscle cramping, mental disorientation, and numb lips and hands are hypocalcemia’s severe symptoms. Calcium and phosphate ions release promote bone repair by controlling osteoblast and osteoclast activation. The calcium in the serum is affected by the phosphate level. There is an inverse relationship between calcium and phosphate in the body, meaning that phosphate levels decrease as calcium levels in the serum increase. PTH regulates calcium and phosphorus concentrations in the serum. Therefore, calcium and phosphorus interact to affect bone metabolism in the body.
Low blood calcium causes the release of PTH from the parathyroid gland (step 1).
PTH leads to the release of calcium from bones (step 2), leading to an increase in the serum calcium level (step 6a).
PTH affects the kidney by increasing the kidney’s conversion of 25-dihydroxy cholecalciferol to calcitriol (step 3). Calcitriol enhances calcium absorption in the brush borders of the intestine (step 6c), increasing serum calcium levels.
PTH acts on the kidney (step 4) to reduce calcium loss in urine by increasing its reabsorption, leading to increased serum calcium levels (step 6b).
Bibliography
Hall JE, Hall ME. Guyton and Hall Textbook of Medical Physiology. 14th ed. Elsevier – Health Science; 2020.
Shaker JL, Deftos L. Calcium and Phosphate Homeostasis. PubMed. Published 2000. Web.