NDT Advance Access originally published online on March 8, 2008
Nephrology Dialysis Transplantation 2008 23(5):1781; doi:10.1093/ndt/gfn042
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Reply
Correspondence and offprint requests to: E-mail: Alex.Woywodt{at}lthtr.nhs.ukSir,
We appreciate the thoughtful comments by Dr Pintavorn and the opportunity to provide some more information on the vexing and little known issue of drug-induced phospholipidosis.
First, Dr Pintavorn points out that amiodarone, which we listed as another drug that is capable of causing phospholipidosis, has never been proven to result in renal deposits in humans. A number of reports have reported histology-proven renal phospholipidosis in animal models. Mortuza and co-workers observed lipid accumulation in the lung and liver of amiodarone-treated rats [1]. Baronas and colleagues showed accumulation of inclusions in the kidney of rats treated with amiodarone [2]. Many patients on amiodarone receive anticoagulation with aspirin if not warfarin. There is often a compelling reason for such anticoagulation, such as a coronary stent or cardiac valve replacement. Many nephrologists are reluctant to proceed to biopsy in this scenario and rightly so. It is therefore, we believe, conceivable that cases of mild renal phospholipidosis are lurking among many patients with cardiac disease and renal impairment in whom vascular disease is assumed. Similar surprises have been encountered in renal biopsies from lung transplant recipients in whom nephrologists are equally reluctant to perform renal biopsies [3,4].
Furthermore, Dr Pintavorn questions our statement that we had performed unnecessary tests in our patient. He postulates that measurement of enzymatic activity and/or mutational analysis of the 
-galactosidase gene are necessary and useful in obtaining the correct diagnosis. We agree that such studies are parts of a complete work-up of patients with phospholipidosis of unknown origin. However, in our elderly female patient with no family history and lack of classical manifestations the thought of drug-induced phospholipidosis did not even cross our minds. We embarked on all of these sophisticated tests before we had done our basic homework. What is more, we caused a lot of worries in our patient and her relatives by assuming a diagnosis of Fabry's disease. Testing for enzyme activity and mutations may not have been entirely unnecessary but they were performed without a proper framework and thinking about the differential diagnosis. We assume that the patient and her relatives would have been reassured if we had considered drug-induced phospholipidosis. Instead, we were carried away by the ‘zebra’ diagnosis, a fate we share with many junior doctors before. To emphasize this common mistake and to deliver some facts on drug-induced phospholipidosis were the main teaching points of our little article.
Conflict of interest statement. None declared.
1 Renal Unit, Lancashire Teaching Hospitals, Preston, UK 2 Nephrology and Transplantation Research Lab, University of Alberta, Canada
References
- Mortuza GB, Neville WA, Delaney J, et al. Characterisation of a potential biomarker of phospholipidosis from amiodarone-treated rats. Biochim Biophys Acta (2003) 1631:136–146.[Medline]
- Baronas ET, Lee JW, Alden C, et al. Biomarkers to monitor drug-induced phospholipidosis. Toxicol Appl Pharmacol (2007) 218:72–8.[CrossRef][Web of Science][Medline]
- Schwarz A, Mengel M, Haller H, et al. Polyoma virus nephropathy in native kidneys after lung transplantation. Am J Transplant (2005) 5:2582–5.[CrossRef][Web of Science][Medline]
- Goes NB, Colvin RB. Case records of the Massachusetts General Hospital. Case 12–2007. A 56-year-old woman with renal failure after heart-lung transplantation. N Engl J Med (2007) 356:1657–65.
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