Elemental formula associated hypophosphataemic rickets

S Uday; S Sakka; J H Davies; T Randell; V Arya; C Brain; M Tighe; J Allgrove; P Arundel; R Pryce; W Högler; N J Shaw

doi:10.1016/j.clnu.2018.09.028

Elemental formula associated hypophosphataemic rickets

Clin Nutr. 2019 Oct;38(5):2246-2250. doi: 10.1016/j.clnu.2018.09.028. Epub 2018 Sep 28.

Authors

S Uday¹, S Sakka², J H Davies³, T Randell⁴, V Arya⁵, C Brain⁵, M Tighe⁶, J Allgrove⁵, P Arundel⁷, R Pryce⁸, W Högler¹, N J Shaw⁹

Affiliations

¹ Department of Endocrinology and Diabetes, Birmingham Children's Hospital, Birmingham, UK; Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK.
² Department of Endocrinology and Diabetes, Birmingham Children's Hospital, Birmingham, UK.
³ Department of Endocrinology and Diabetes, University Hospital Southampton, Southampton, UK.
⁴ Department of Paediatric Endocrinology and Diabetes, Nottingham Children's Hospital, Nottingham, UK.
⁵ Department of Paediatric Endocrinology, Great Ormond Street Hospital, London, UK.
⁶ Poole Hospital NHS Foundation Trust, Poole, UK.
⁷ Department of Metabolic Bone Disease, Sheffield Children's Hospital, Sheffield, UK.
⁸ Department of Paediatrics, Royal Gwent Hospital, Newport, UK.
⁹ Department of Endocrinology and Diabetes, Birmingham Children's Hospital, Birmingham, UK; Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK. Electronic address: nick.shaw@nhs.net.

PMID: 30314926
DOI: 10.1016/j.clnu.2018.09.028

Abstract

Objectives: Hypophosphataemic rickets (HR) is usually secondary to renal phosphate wasting but may occur secondary to reduced intake or absorption of phosphate. We describe a series of cases of HR associated with the use of Neocate^®, an amino-acid based formula (AAF).

Methods: A retrospective review of cases with HR associated with AAF use presenting to centres across the United Kingdom.

Results: 10 cases were identified, over a 9 month period, all associated with Neocate^® use. The age at presentation was 5 months to 3 years. The majority (8/10) were born prematurely. Gastro oesophageal reflux disease (6/10) was the most frequent indication for AAF use. Radiologically apparent rickets was observed after a median of 8 months (range 3-15 months) of exclusive Neocate^® feed. The majority (7/10) were diagnosed on the basis of incidental findings on radiographs: rickets (6/10) or fracture with osteopenia (5/10). All patients had typical biochemical features of HR with low serum phosphate, high alkaline phosphatase, normal serum calcium and 25 hydroxyvitamin D. However, in all cases the tubular reabsorption of phosphate (TRP) was ≥96%. Phosphate supplementation resulted in normalisation of serum phosphate within 1-16 weeks, and levels remained normal only after Neocate^® cessation. In patients with sufficient follow up duration (4/10), normalisation of phosphate and radiological healing of rickets was noted after 6 months (range: 6-8 months) following discontinuation of Neocate^®.

Conclusion: The presence of a normal TRP and resolution of hypophosphataemia and rickets following discontinuation of Neocate^® indicates this is a reversible cause likely mediated by poor phosphate absorption. Close biochemical surveillance is recommended for children on Neocate^®, especially in those with gastrointestinal co-morbidities, with consideration of a change in feed or phosphate supplementation in affected children.

Keywords: Amino acid based formula; Child; Hypoallergenic feed; Neocate(®); Phosphate; Rickets.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Amino Acids / adverse effects*
Bone and Bones / diagnostic imaging
Bone and Bones / pathology
Carbohydrates / adverse effects*
Child, Preschool
Dietary Fats / adverse effects*
Female
Humans
Infant
Infant Formula
Male
Phosphates* / blood
Phosphates* / metabolism
Phosphates* / therapeutic use
Retrospective Studies
Rickets, Hypophosphatemic*

Substances

Amino Acids
Carbohydrates
Dietary Fats
Neocate
Phosphates