Diagnostic relevance of pyuria in haemodialysis patients [renal tuberculosis as an A etiology of sterile pyuria]

ABSTRACT

This study was designed to assess the significance of pyuria as a marker of urinary tract infections [UTIs] in haemodialysis patients and renal tuberculosis as a common a etiology of sterile pyuria. The study was conducted on 50 patients with end stage renal disease [ESRD] on regular haemodialysis [group I], as well as 10 healthy controls [group II]. Fresh urine samples were cultured, examined microscopically for pyuria and tested by Bayer reagent strips for protein, blood, nitrite and leucocyte esterase [LE]. Gram stain of colonies and their identification to the species level using API 20 E system were performed. Ziehl-Neelson [ZN] staining for acid alcohol fast bacilli and Polymerase chain reaction [PCR] for detection of Mycobacterium tuberculosis [MTB] DNA were performed on 24 hours collected urine samples. All patients had pyuria [>/= 5 WBCs/hpf]. Protein, blood, LE and nitrite were significantly higher in patients than in controls [P value <0.01, <0.01, <0.001 and <0.05 respectively]. A significant correlation was found between patients' symptoms and bacterial growth [p<0.1]. Thirty one patients had sterile pyuria; three out of them [10%] were proved to be tuberculous by ZN or PCR. To conclude, pyuria is a common finding in haemodialysis patients and is proved to be a valuable parameter of UTIs in these patients. In symptomatic patients with sterile pyuria, renal tuberculosis should be excluded by ZN staining and/or PCR. In asymptomatic patients, periodic urine culture should be performed to confirm presence or absence of UTIs