Rule of parathyroid hormone and vitamin D investigations in metabolic bone disease of prematurity diagnosis and management

Mohamed Fatouh

doi:10.1530/endoabs.78.P10

Background: Metabolic bone disease of prematurity (MBDP) is characterized by decreased bone density as a result of insufficient mineral deposition in the bones of premature babies. Although the primary cause of MBDP is different from one case to another; either hypocalcaemia or hypophosphataemia, the main current practice is to treat it with phosphate supplements.

Objectives: To emphasize the rule of parathyroid hormone and vitamin D investigations in MBDP diagnosis and management.

Methods: Data were collected retrospectively between March 2019 and June 2020 from the patients` notes and hospital electronic systems in a UK tertiary neonatal unit. Babies born at 29 weeks or less with a diagnosis of MBDP at discharge were included in the study.

Results: In total, twelve babies were included with different gestational ages as illustrated in table 1. Five of them did not show any improvement over the routine treatment with phosphate supplements at 1 mmol/kg once daily. Therefore, PTH and vitamin D levels were investigated; the earliest of which was done after 4 weeks from starting the treatment. Three out of five babies had high PTH and low vitamin D. Therefore, phosphate supplements were stopped and calcium was started. Subsequently, the parathyroid hormone levels normalized shortly after starting calcium supplements. Furthermore, the MBDP incidence was noted to be related to high diuretic use, corticosteroids, low gestational age and prolonged use of parenteral nutrition.

Table 1 Shows the classification of included babies according to their gestation age at birth.
Gestational age	23 weeks	24 weeks	25 weeks	26 weeks	28 weeks	29 weeks
Number	1	2	5	1	2	1

Conclusion: MBDP incidence in our local unit was 21% during the study period. Quarter of the patients had hyper-parathyroidism as a result of either inappropriate initial treatment with phosphate supplements or preliminary low calcium or vitamin D. Although the main aim is to prevent the MBDP incidence, consideration of earlier investigation of both parathyroid hormone and vitamin D is of an equal importance for guidance of the appropriate treatment course of MBDP.

Abbreviations: MBDP: metabolic bone disease of prematurity.

PTH: parathyroid hormone.

Endocrine Abstracts

P10