FCM Hypophosphataemia Duration Weeks — ESENeph MCQ

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HardElectrolyte DisordersFCM Hypophosphataemia Duration WeeksESENeph

After repeated ferric carboxymaltose infusions, a patient develops weakness, bone pain, phosphate 0.42 mmol/L, low tubular phosphate reabsorption and raised intact FGF23. What is the best management?

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Correct answer: C — Stop ferric carboxymaltose and correct phosphate

Ferric carboxymaltose can increase biologically active FGF23, causing renal phosphate wasting, low calcitriol and sometimes osteomalacia. Further exposure should be avoided; symptomatic severe hypophosphataemia is treated and monitored, and an alternative intravenous iron formulation with a lower hypophosphataemia risk should be chosen if parenteral iron is still required. The competing options do not fit the renal phenotype, temporal relationship, treatment threshold or safety constraint described. Management still requires confirmation of current medicines, renal trajectory and relevant contraindications, followed by timely biochemical and clinical reassessment. Escalate urgently if life-threatening electrolyte disturbance, respiratory compromise, shock, neurological deterioration or a dialysis indication develops.

Reference: BNF: Prescribing in renal impairment. https://bnf.nice.org.uk/medicines-guidance/prescribing-in-renal-impairment/