In our article we explained the need to distinguish between urinary tract infections and asymptomatic bacteriuria. The term asymptomatic urinary tract infection should be avoided. Clinical practice requires the differentiation between a disease and a condition – the latter requires treatment only in rare, individual cases (for example, eradication of asymptomatic bacteriuria in pregnant women). We refer our readers to the current German guidelines (1, 3) on diagnosis and therapy, where this terminology was consented. This differentiation should ensure that only infections, not bacteriological findings are treated as suggested by Fiegel and Höffler.
With regard to the relevance of leukocytes in urine, which Dr Roleff and Professor Petersen mention, we wish to add that the lack of a microscopic finding of leukocytes has a negative predictive value of 95%, making it suitable for ruling out an infection. However, according to a meta-analysis, the sensitivity is only 37–96% and therefore less suitable for detecting the pathology (2). On this background, we question Dr Roleff's postulate that microscopic urine examination ought to be possible in the primary care setting. Dysuria (or the patient’s reporting of “a burning sensation when urinating”) is not pathognomonic—and our article did not say it was. Reports of typical problems in the medical history (“burning sensation when urinating”) do, however, increase the probability that a UTI is present. Dysuria, though very occasionally present in (individual) cases of bladder cancer, is of very limited value with regard to diagnosing malignancies, due to their low prevalence, as well as low sensitivity and specificity of the symptom. “The gold standard to diagnose UTI in presence of typical symptoms is a bacteriological urine culture, with identification and quantification of the pathogen and sensitivity testing.” This definition was agreed upon by the author group of the S3 guideline for UTI in the Association for Scientific Medical Societies in Germany (AWMF, http://www.uni-duesseldorf.de/AWMF/). The method of collecting urine, as criticized by Fiegel and Höffel, was not part of this definition. Depending on how the urine was collected, different pathogen numbers are indicative of a diagnosis; several articles have compared the bacteriological findings from bladder puncture with other forms of collecting urine. Bladder puncture undoubtedly yields high quality specimens, but for various reasons (risk of injury, cost) it is not appropriate for routine diagnostic evaluation in adults in primary care. The situation may well be different for neonates/infants. The study mentioned by Fiegel and Höffer examined the (specialized) clientele of a nephrology outpatient ward and therefore cannot be translated to the situation in primary care.
Dr. med. Eberhard Kniehl
Prof. Dr. med. Eva Hummers-Pradier
Dr. med. Guido Schmiemann MPH
Institut für Allgemeinmedizin
Medizinische Hochschule Hannover, 30625 Hannover, Germany
Conflict of interest statement
The authors declare that no conflict of interest exists according to the guidelines of the International Committee of Medical Journal Editors.
|1.||Schmiemann G, Gebhardt K, Matejczyk M, Hummers-Pradier E: Brennen beim Wasserlassen – Anwenderversion der S3-Leitlinie Harnwegsinfekte. Düsseldorf: Omicron publishing 2009.|
|2.||Whiting P, Westwood M, Bojke L, Palmer S, Richardson G, Cooper J, et al.: Clinical effectiveness and cost-effectiveness of tests for the diagnosis and investigation of urinary tract infection in children: a systematic review and economic model. Health technology assessment 2006;10(36): 1–154. VOLLTEXT|
|3.||Epidemiologie, Diagnostik, antimikrobielle Therapie und Management von erwachsenen Patienten mit Harnwegsinfektionen Nr. 043/044 (in press) http://www.uni-duesseldorf.de/WWW/AWMF/ll/043–044-m.htm|
|4.||Schmiemann G, Kniehl E, Gebhardt K, Matejczyk M, Hummers-Pradier E: The diagnosis of urinary tract infection: A systematic review. Dtsch Arztebl Int 2010; 107(21): 361–7 VOLLTEXT|