(p. 687) Hypercalcaemic and hypocalcaemic syndromes in children 

The calcium-regulating system employs an intricate network of homoeostatic signals and targets in order to meet the body’s mineral demands. Mineral requirements vary considerably throughout progressive stages of development, in large part reflecting the changing mineral demands of skeletal growth, and representing characteristic features of the calcium homoeostatic system during childhood years. As a consequence, this system must be adaptable to the wide-ranging mineral demands occurring throughout the life cycle. Furthermore, the numerous factors involved in calcium homoeostasis allow for compensatory mechanisms to limit the severity of disease when an isolated insult occurs to the system. Indeed, many heritable disorders of mineral homoeostasis become evident in early childhood and are best recognized when viewed in the light of mineral requirements during infancy and childhood. As understanding of the relevant physiology is central to formulating approaches to management of such problems, we review these disorders in the context of physiology specific to childhood to provide the basis for understanding hypocalcaemia and hypercalcaemia in this age group.