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CKD-MBD – phosphate binders — RACP Paediatrics MCQ

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HardNephrologyCKD-MBD – phosphate bindersRACP Paediatrics

A child with stage 4 CKD has persistent phosphate 2.2 mmol/L and PTH three times the upper limit despite correction of nutritional vitamin-D deficiency and an appropriate dietary-phosphate plan. Calcium is low-normal. Which medication should now be added specifically to reduce intestinal phosphate absorption?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: D — Start an oral phosphate binder with meals, selected according to calcium balance

Explanation lettering: E = shown as A · D = shown as B · A = shown as C · C = shown as D · B = shown as E

C is correct. Persistent hyperphosphataemia despite dietary management requires a phosphate binder taken with meals; calcium level and calcification risk determine calcium-containing versus non-calcium selection. D may be used for selected secondary hyperparathyroidism after phosphate and vitamin-A status are addressed, but active vitamin A alone can worsen phosphate loading. E treats selected CKD anaemia, not intestinal phosphate absorption. A treats iron deficiency and does not correct CKD mineral-bone disorder. B treats metabolic acidosis and is not a phosphate binder. Serial phosphate, calcium, PTH and vitamin-A assessment is required rather than treating one laboratory value in isolation.

Reference: Royal Children’s Hospital Melbourne: Hyperphosphataemia: https://www.rch.org.au/clinicalguide/guideline_index/Hyperphosphataemia/