Hungry bone syndrome and normalisation of renal phosphorus threshold after total parathyroidectomy for tertiary hyperparathyroidism in X-linked hypophosphataemia: a case report.

Rachel K Crowley,Thomas FJ King,Mark Kilbane,Myra O’Keane,Malachi J McKenna,Michelle Morrin

doi:10.1186/1752-1947-8-84

Rachel K Crowley, Thomas FJ King + Show 4 more

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https://doi.org/10.1186/1752-1947-8-84

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Abstract

IntroductionThis is the first report of which the authors are aware to describe this c.2166delinsGG mutation in X-linked hypophosphataemia and to describe normalisation of renal threshold for phosphate excretion after parathyroidectomy for tertiary hyperparathyroidism in X-linked hypophosphataemia.Case presentationWe present the case of a 34-year-old Caucasian woman with X-linked hypophosphataemia. She developed tertiary hyperparathyroidism with markedly high bone turnover requiring total parathyroidectomy and had prolonged requirement for intravenous calcium infusion after surgery. She had a novel mutation in her phosphate-regulating gene with homologies to endopeptidases on the X-chromosome and had an unusual degree of dependence on phosphate supplementation. Prior to operative intervention she had a trial of cinacalcet that improved bone turnover markers when used in isolation but which led to a paradoxical rise in parathyroid hormone levels when given with phosphate supplementation. After correction of hungry bone syndrome, the renal phosphorus threshold normalised as a manifestation of hypoparathyroid state despite marked elevation in level of fibroblast growth factor 23.ConclusionsThis case illustrates the risk of tertiary hyperparathyroidism as a complication of treatment for hypophosphataemia; it highlights the morbidity associated with hungry bone syndrome and provides novel insight into renal handling of phosphorus.

Highlights

This is the first report of which the authors are aware to describe this c.2166delinsGG mutation in X-linked hypophosphataemia and to describe normalisation of renal threshold for phosphate excretion after parathyroidectomy for tertiary hyperparathyroidism in X-linked hypophosphataemia.Case presentation: We present the case of a 34-year-old Caucasian woman with X-linked hypophosphataemia
This case illustrates the risk of tertiary hyperparathyroidism as a complication of treatment for hypophosphataemia; it highlights the morbidity associated with hungry bone syndrome and provides novel insight into renal handling of phosphorus
X-linked hypophosphataemia (XLH) is a congenital cause of renal phosphorus wasting as a consequence of inactivating mutations in the phosphate-regulating gene with homologies to endopeptidases on the X chromosome (PHEX) that manifests with rickets and poor linear growth in childhood [1]

Summary

Conclusions

This case report illustrates the challenges of management of XLH after tertiary hyperparathyroidism has developed, and supports improved liaison between paediatric and adult endocrine and rheumatology services to optimise care and prevent development of iatrogenic complications. The case suggests a potential role for PTH in the phosphaturic action of FGF23, which will be of interest to endocrinologists and nephrologists. Consent Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal. Competing interests The authors declare that they have no competing interests. Authors’ contributions RC, TK and MMcK were responsible for collating clinical material and drafting the manuscript. MK, MM and MO’K were responsible for laboratory measurements. All authors read and approved the final manuscript

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