Blastocystis infection in patients with chronic renal disease.

The Brazilian Journal of Infectious Diseases 2009;13(1):1. Copyright© 2009 by The Brazilian Journal of Infectious Diseases and Contexto Publishing. All rights reserved. I have read with interest the paper by Kulik et al. published in the fourth issue of 2008 regarding Blastocystis sp. infection in patients with chronic renal disease undergoing hemodialysis [1]. Blastocystis had long been disregarded as a cause of disease; however, there is recent interest in its potential role in causing gastrointestinal and extra intestinal symptoms [2]. Unfortunately, the role of Blastocystis as a cause of disease is far from completely understood, as the study of several factors, such as number of parasites seen per high power field, morphology, host immune status, response to treatment, laboratorial techniques utilized and genetic sub typing have shown contradictory data. There is also a lack of a sufficient number of well-designed clinical trials addressing its potential pathogenic character [3]. Ruling out other likely sources of gastrointestinal illness is essential when trying to attribute symptoms to Blastocystis sp., and efforts are normally made towards eliminating other causes, such as bacteria, fungi, virus and those of non-infectious origin [3]. Chronic renal failure is a known cause of diarrhea per se [4]. For these reasons I would advise the clinician to make a thorough investigation of alternative diarrheal causes before treating Blastocystis infection. When appropriate, metronidazole can be used in patients with varying levels of renal disease, whether on dialysis or not [5].