Chapter 46 - Primary Hyperparathyroidism and Other Causes of Hypercalcemia in Children and Adolescents

Abstract

Primary hyperparathyroidism and other causes of hypercalcemia occur far less commonly in children than in adults. The mechanisms of hypercalcemia in children are similar to those that occur in adults, but the smaller size and relative immaturity of the skeleton and kidney make children particularly sensitive to factors that affect renal handling of calcium and bone remodeling. An increase in net calcium mobilization from the skeleton is most often the cause of hypercalcemia, although excess intestinal absorption of calcium can also lead to hypercalcemia. Regardless of the underlying pathophysiology, hypercalcemia occurs when excessive transport of calcium from the skeleton and/or gut into the extracellular fluid exceeds the ability of the kidney to excrete the increased filtered load. The clinical features are dependent on the underlying disorder, age of the child, and degree of hypercalcemia. Children may be more adaptive to hypercalcemia compared to adults, and infants and children with mild hypercalcemia may not have any symptoms. With moderate to severe hypercalcemia, symptoms —such as anorexia, vomiting, and constipation (rarely diarrhea) may occur.