Urinary Tract Infections

Bladder infections, kidney infections, and what it means when they keep coming back.

Types of urinary infection

A bladder infection (cystitis) causes burning with urination, frequency, urgency, lower abdominal discomfort, and sometimes visible blood. It is uncomfortable but not dangerous in an otherwise healthy person.

A kidney infection (pyelonephritis) is more serious. It adds fever, chills, flank or back pain, nausea, and a general sense of being genuinely ill. It needs prompt treatment.

Asymptomatic bacteriuria means bacteria are present in the urine without symptoms. In most people this does not need antibiotics — treating it drives resistance without helping. Pregnancy and certain pre-procedure situations are the exceptions.

Why they happen

Women get urinary infections far more often than men, largely because the urethra is short. Sexual activity, menopause and the tissue changes that follow, certain contraceptives, and incomplete emptying all raise the risk.

In men, urinary infection is less common and more likely to point to an underlying cause — an enlarged prostate causing retention, a stone, or a prostate infection. A man with a genuine urinary infection generally deserves a urologic evaluation.

Diagnosis and treatment

We confirm with a urinalysis and, when it matters, a urine culture that identifies the organism and the antibiotics it responds to. Culture is especially important with recurrent infections, recent antibiotic use, or when the first treatment fails.

Uncomplicated bladder infections are treated with a short antibiotic course. Kidney infections require longer treatment and sometimes hospitalization. Take the entire course even once you feel better, which is usually within a day or two.

Recurrent infections

Recurrent infection is generally defined as two in six months or three in a year. At that point the question shifts from treating episodes to finding out why they keep happening. Evaluation may include imaging of the kidneys, cystoscopy to look inside the bladder, and a post-void residual measurement.

Preventive strategies include adequate fluid intake, urinating after intercourse, vaginal estrogen for postmenopausal women — which is genuinely effective and often underused — and in selected cases low-dose preventive antibiotics. Cranberry and D-mannose have modest evidence; they are reasonable to try, but not a substitute for evaluation.