Common errors in diagnosis and management of urinary tract infection. I: Pathophysiology and diagnostic techniques

Extract

The problem

Urinary tract infection (UTI) is one of the most common diseases, occurring from the neonate up to geriatric age groups. Forty to 50% of adult women have a history of at least one UTI [1]. UTI is a major cause of Gram-negative sepsis in hospitalized patients and after renal transplantation [2]. General practicioners, paediatricians, urologists, and nephrologists are frequently consulted because of symptoms suggestive of UTI, but there are large differences in the management of such patients with respect to definition of UTI, diagnosis, and treatment. In particular, the clinical relevance of low-count bacteriuria and asymptomatic UTI as well as the potential indications for antimicrobial therapy continue to be controversial.

UTI defines a condition in which the urinary tract is infected with a pathogen causing inflammation. There is consensus that most uropathogenic micro-organisms such as Escherichia coli colonize the colon, the perianal region, and in females the introitus vaginae and the periurethral region. Facultatively they may further ascend to the bladder and/or to the kidneys. If structures of the urinary tract are invaded, accurate diagnosis and treatment are necessary in order to ensure optimal management and to prevent further complications. UTI results from the interaction between uropathogen and the host. The micro-organisms may have particular uropathogenic properties, explaining the occurrence of infection in an otherwise normal urinary tract. On the other hand, non-uropathogenic strains can induce acute infection in the presence of urological abnormalities, or when the host's defence mechanisms are impaired: in paedriatric patients and old age, pregnancy, diabetes, and in the immunocompromized patient including renal transplant recipients.