New UTI Classification: From Uncomplicated to Localised/Systemic

Urinary tract infections (UTIs) are a common medical issue, representing up to 5% of primary care visits. Traditionally, UTIs have been classified as either uncomplicated or complicated, a model introduced in 1963 and refined in 1992. Complicated UTIs typically occur in individuals with anatomical or functional urinary tract abnormalities, immunosuppression, male sex, or pregnancy. However, this classification lacks consideration of clinical severity, pathogen traits, and risk factors that influence treatment complexity and outcomes.

To address these limitations, the EAU Guidelines Panel on Urological Infections proposes a new classification system that emphasizes the patient’s clinical condition and risk profile. The ORENUC system, introduced in 2011, categorizes patients into six risk groups:O – no known risks,R – recurrent UTI risk factors,E – extra-urogenital factors,N – nephropathy,U – urological conditions manageable with therapy,C – catheter-associated risks.

In addition, the panel suggests classifying UTIs into localised and systemic types. Localised UTIs, such as cystitis, present with symptoms like dysuria and urgency but lack systemic signs. Systemic UTIs involve symptoms like fever, chills, delirium, or hypotension, indicating more severe infection and often requiring intravenous antibiotics and further diagnostics.

Risk factors that complicate both types include age (paediatric or frail elderly), catheter use, urinary tract obstruction, immunosuppression, recent antibiotic use, and a history of resistant pathogens. This refined classification aims to support better clinical decisions and personalized treatment strategies.