Duncan Andrew, Yacoubian Calum, Watson Neil, Morrison Ian
Scottish Trace Element and Micronutrient Reference Laboratory, Glasgow Royal Infirmary, Glasgow, UK.
Department of Paediatric Surgery, Yorkhill Hospital, Glasgow, UK.
J Clin Pathol. 2015 Sep;68(9):723-5. doi: 10.1136/jclinpath-2014-202837. Epub 2015 Jun 17.
In high doses zinc may cause copper deficiency, a diagnosis that is often missed resulting in anaemia, neutropenia and irreversible neurological symptoms. The aim of this study was to assess if zinc deficiency is erroneously diagnosed by misinterpretation of plasma zinc concentrations and whether copper deficiency is induced in patients prescribed zinc.
Casenotes of 70 patients prescribed zinc were scrutinised. Plasma concentrations of zinc, copper, C reactive protein and albumin were recorded from the laboratory database.
62% of patients were prescribed zinc at doses sufficient to cause copper deficiency. In 48% of the patients, plasma zinc concentrations were low as a probable result of hypoalbuminaemia or the systemic inflammatory response rather than deficiency. Awareness of copper deficiency was lacking; it was only documented as a possible side effect in one patient and plasma copper was measured in only two patients prescribed zinc. 9% of patients developed unexplained anaemia and 7% developed neurological symptoms typical of copper deficiency.
Zinc deficiency is frequently misdiagnosed on the basis of low plasma zinc concentrations. The potential risk of copper deficiency developing in patients prescribed high doses of zinc is apparently infrequently considered. It is probable that a significant minority of patients prescribed with high doses of zinc develop iatrogenic copper deficiency.
高剂量锌可能导致铜缺乏，而这一诊断常常被漏诊，进而导致贫血、中性粒细胞减少及不可逆的神经症状。本研究的目的是评估血浆锌浓度的误判是否会导致锌缺乏的错误诊断，以及接受锌治疗的患者是否会引发铜缺乏。
仔细审查了70例接受锌治疗患者的病历。从实验室数据库记录锌、铜、C反应蛋白和白蛋白的血浆浓度。
62%的患者所服用的锌剂量足以导致铜缺乏。48%的患者血浆锌浓度较低，这可能是低白蛋白血症或全身炎症反应的结果，而非锌缺乏所致。对铜缺乏缺乏认识；仅有1例患者记录了铜缺乏可能是副作用，且仅有2例接受锌治疗的患者检测了血浆铜。9%的患者出现不明原因的贫血，7%的患者出现典型的铜缺乏神经症状。
基于低血浆锌浓度，锌缺乏常被误诊。高剂量锌治疗患者发生铜缺乏症的潜在风险显然很少被考虑。很可能相当一部分接受高剂量锌治疗的患者会发生医源性铜缺乏。
