Prevalence and Clinical Characteristics of Asymptomatic Pyuria in Chronic Kidney Disease

BACKGROUND: Pyuria seems to be common in chronic kidney disease (CKD), irrespective of urinary tract infection (UTI). It has been hypothesized that sterile pyuria occurs in CKD because of chronic renal parenchymal inflammation. However, there are limited data on whether CKD increases the rate of pyuria or how pyuria in CKD should be interpreted. We investigated the prevalence and characteristics of asymptomatic pyuria (ASP) in CKD via urinary white blood cell (WBC) analysis.METHODS: Urine examination was performed for all stable hemodialysis (HD) and non-dialysis CKD patients of the outpatient clinic (total N=298). Patients with infection symptoms or recent history of antibiotic use were excluded. Urine culture and WBC analysis were performed when urinalysis revealed pyuria.RESULTS: The prevalence of ASP was 30.5% (24.1% in non-dialysis CKD and 51.4% in HD patients). Over 70% of the pyuria cases were sterile. The majority of urinary WBCs were neutrophils, even in sterile pyuria. However, the percentage of neutrophils was significantly lower in sterile pyuria. In multivariate logistic regression analysis, the degree of pyuria, percentage of neutrophils, and presence of urinary nitrites remained independently associated with sterile pyuria.CONCLUSIONS: The prevalence of ASP was higher in CKD patients and increased according to CKD stage. Most ASP in CKD was sterile. Ascertaining the number and distribution of urinary WBCs may be helpful for interpreting ASP in CKD.

A Case of Incidentally Detected Asymptomatic Emphysematous Pyelonephritis / 대한내과학회지

Emphysematous pyelonephritis (EPN) is a severe gas-forming infection of the renal parenchyma and surrounding tissues. Patients with EPN commonly present with high fever, chills, and flank pain. These symptoms mimic a simple urinary tract infection, such that diagnosis is often delayed. Because of its life-threatening fulminant course, the early detection of EPN and its prompt treatment with intravenous antibiotics with or without percutaneous drainage are critical. Here we describe a case of a 63-year-old Korean female with diabetes mellitus who had no specific symptoms or signs of EPN. A chest computed tomography (CT) scan to assess a right pleural effusion incidentally detected an abnormal gas shadow in the renal parenchyma. An abdominal CT scan performed 5 days later showed increased gas within the kidney parenchyma, but the patient still had no symptoms of EPN. She was treated with intravenous antibiotics alone. A follow-up abdominal CT scan revealed the complete disappearance of the features of EPN.