Methods of Investigation
The clinical diagnosis of urinary tract infection is beset by a high rate of errors, if the examination methods are faulty. Even in a primary care practice, microscopic urinalysis should be possible in order to make a diagnosis. So called asymptomatic urinary tract infections may require treatment in chronic urological pathologies. Primary attempts to treat a presumed urinary tract infection with fluoroquinolones often lead to antimicrobial resistance. Cotrimoxazole, amoxicillin, or nitrofurantoin may be used successfully.
The gold standard for a diagnosis of urinary tract infection, as the authors write, lies in identifying the causative agent by means of urine culture from midstream urine. Experiences from urological practice have shown that immersion culture media are often colonized by three or more pathogens, as a result of secondary contamination. After cleaning the external genitalia, bacteria should be identified in midstream urine by using a dipstick test, and antibiotic treatment should be given if significant bacteriuria (more than 100 000 pathogen germs/ml urine) is present. Pathogen concentrations of 10 000 require control examinations. And even a number of 1000 pathogens can indicate a urinary tract infection in isosthenuria. In case of doubt, catheter examination will clarify the cause and enable a diagnosis.
“A burning sensation while urinating” in the patient's medical history is not pathognomonic for cystitis and also applies to bladder cancer.
Performing solely urinalysis by dipstick testing is certainly not sufficient to make a diagnosis. An absence of nitrites does not exclude a urinary tract infection.
The urine finding enables an exact diagnosis by conducting a dipstick test of midstream urine or catheter urine and by determining the causative strain and resistance patterns and microscopic findings.
Dr. med. Hans-Bernd Roleff
41063 Mönchengladbach, Germany
|1.||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|