[Metabolic bone disorders: what the internist must not overlook].

BACKGROUND

Metabolic bone disorders are common, albeit underestimated, causes of fractures and chronic bone pain in internal medicine. They can remain asymptomatic for long periods and are frequently only diagnosed when insufficiency fractures occur.

AIM OF THE STUDY: The aim of this review article is to discuss common and rare metabolic bone disorders and to outline a practice-oriented diagnostic approach.

MATERIALS AND

METHODS

Narrative review of current literature with particular emphasis on clinically relevant differential diagnoses and diagnostic algorithms.

RESULTS

In addition to secondary osteoporosis, disorders of calcium and phosphate metabolism play a central role. Important differential diagnoses include primary hyperparathyroidism, genetic osteopathies, hypophosphatasia, and fibroblast growth factor 23 (FGF23)-mediated hypophosphataemia. Crucial for diagnosis are a structured medical history, the measurement of calcium, phosphate, magnesium, parathyroid hormone and alkaline phosphatase, as well as, where necessary, further parameters such as tubular maximum for phosphate reabsorption per glomerular filtration rate (TMP/GFR) and FGF23. Magnetic resonance imaging is essential for detecting insufficiency fractures.

CONCLUSION

A systematic approach to the diagnosis of metabolic bone diseases is crucial, as this directly determines different therapeutic implications, and specific treatment options are increasingly becoming available.