Endocrine Abstracts

Parenteral iron is commonly used in management of iron deficiency especially due to gastrointestinal, obstetrics and gynaecological bleeding. There is a variety of intravenous iron formulations available nowadays and they are generally preferred over oral iron preparations in raising haemoglobin and ferritin, especially in cases of noncompliance and patients with gastrointestinal problems. However, one of the frequently missed complications of iron transfusions is hypophosphatemia. The precise incidence of iron-induced hypophosphatemia is unclear as it is uncommon to measure phosphate levels after iron infusion. Interestingly, abnormal uterine bleeding is considered an independent risk factor of developing post-iron transfusion hypophosphatemia. We report a case of a 57-year-old lady known for iron deficiency anaemia secondary to heavy uterine bleeding who developed hypophosphatemia following parenteral iron transfusion (Ferinject-Ferric Carboxymaltose). The patient presented to the medical assessment unit with worsening frontal headache associated with vomiting, blurred vision, and a metallic taste over a 10-day period after having an iron infusion. She was active, independent and had received 2-3 iron transfusions in the past. Additionally, she was on hormone replacement therapy (Evorel Sequi patches), and had two doses of COVID vaccine, otherwise, her past medical and social history was unremarkable. On admission, her serum phosphate was 0.41 mmol/l and calcium was 2.25 mmol/l. Routine blood tests, inflammatory markers, bone profile, and CT-head were all normal. She was treated with 3 doses of phosphate infusion (Phosphate Polyfusor), each dose administered as 50 mmol/500mL over 24 hours, and subsequently her symptoms dramatically improved. Hypophosphatemia is commonly asymptomatic and often incidental. However, in severe cases serious complications including but not limited to osteomalacia, bone fractures, heart failure, seizures, and coma were reported. Awareness of this potential complication is paramount to guide clinical practice and to ensure that patients requiring iron transfusions are well-informed of the risks of hypophosphatemia.