Bacteriuria in a Patient with Incident Delirium

New-onset delirium can be a sign of life-threatening illness. Careful evaluation and follow-up are essential if the patient is sick or the delirium is persistent. Delirium is usually self-limited, however, especially among otherwise well older people with limited cognitive reserve. In such patients, asymptomatic bacteriuria, meaning a positive urine culture without urinary symptoms, is highly prevalent and so will commonly accompany delirium by chance alone. There is no evidence that treating asymptomatic bacteriuria improves delirium outcomes. Expert opinion consistently recommends against this practice. When minor perturbations cause transient cognitive dysfunction, treatment of “UTI” enjoys the same success as other treatments for self-limited illnesses. This is often interpreted as proof that “UTI” caused the delirium. Repeated attempts to sterilize the urine may ensue. But urine is never sterile. Acknowledgment of the urinary microbiome should encourage recalibration of the harm/benefit analysis for antibiotic treatment.