UTI

The first decision is not which antibiotic to prescribe. It is whether the presentation is lower-tract cystitis, upper-tract infection, asymptomatic bacteriuria, or a non-urinary cause of symptoms. Acute uncomplicated cystitis is a clinical diagnosis in a non-pregnant, non-catheterized woman with normal urinary tract anatomy who has typical urinary symptoms such as dysuria, frequency, urgency, or suprapubic discomfort without vaginal discharge or irritation. Empiric treatment without culture is appropriate in this pattern. A positive urine culture by itself does not establish UTI; bacteriuria without urinary symptoms is usually asymptomatic bacteriuria and should not be treated in non-pregnant adults. The same laboratory finding has a different meaning in pregnancy. Pregnant women are screened with urine culture because treating detected asymptomatic bacteriuria modestly lowers the risk of pyelonephritis and low birth weight. In an older adult, confusion or a fall without urinary symptoms or systemic infection is not a urinary diagnosis; investigate delirium rather than reflexively culturing urine and prescribing antibiotics. Fever, rigors, flank or costovertebral-angle pain, vomiting, hypotension, or other systemic features shift the problem toward pyelonephritis or urosepsis. That shift changes...