Disturbances of calcium phosphate metabolism in childhood endocrinopathies – diagnostic problems

The availability of densitometry, determinations of concentration levels of vitamin D, bone turnover markers, and FGF23, combined with progress in genetic diagnostic management allow for an increasingly precise evaluation of developmental-age calcium phosphate metabolism disturbances. It should be remembered that 90% of the peak bone mass is formed by the end of puberty; thus, a proper diagnosis and treatment of disturbances of the calcium phosphorus metabolism in children are a decisive factor affecting the risk of fractures and comfort of life in adults. Attention has recently been focused on the necessity of vitamin D supplementation and on monitoring vitamin D concentration levels, and an increasing number of reports address the association between the VDR gene polymorphism and numerous diseases, but a thorough analysis of the calcium phosphate metabolism is still performed too rarely. Proof may be found in the delayed diagnosis of hyperparathyroidism in children; in spite of the fact that the condition is markedly less common in children as compared to adults, in the former patients its course is highly dramatic. The incidence of primary hyperparathyroidism in children is 2–5/100,000, while other authors report 1/200–300,000, whereas in adults the incidence rate is 1/1000 individuals [1–3]. Contrary to adults, in the majority of children – as many as 79–99% ­– the course of the disease is fully symptomatic, which may result from a higher dynamics of metabolic processes and faster bone turnover in the growth period. Numerous authors emphasize the role of erroneous and markedly delayed diagnostic management of hypercalcaemia symptoms, with the time lapse from the appearance of the initial symptoms to establishing the diagnosis ranging from several months to 2–3 years, which was also confirmed by our observations [2–4]. Children demonstrating weakness and body mass loss, polyuria, polydipsia, bone deformities, and fractures are not subjected to calcium and phosphate level determinations for many months [1, 2]. Prolonged hypercalcaemia may result in secondary complications that are seen in as many as 44% of children with primary hyperparathyroidism; such complications include nephrocalcinosis, peptic ulcers, arterial hypertension, and osteoporosis and they persist in spite of the primary condition having been cured. In this group of patients, an important diagnostic element is a genetic analysis that rules out genetic mutations of the following genes:...


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