UTI

Overview

A urinary tract infection (UTI) is a bacterial infection affecting any part of the urinary system, most commonly the bladder (cystitis). UTIs cause burning urination, urgency, frequency, and cloudy urine. They are far more common in women due to the shorter urethra. Most uncomplicated UTIs in healthy women are straightforward to treat but recurrent UTIs are common.

How common is it?

UTIs are the second most common type of infection after respiratory infections. About 50 to 60% of women will have a UTI at some point. About 3 million GP consultations for UTI occur in the UK each year.

Causes and risk factors

E. coli from the bowel accounts for about 80 to 85% of UTIs. Bacteria enter the urethra and ascend to the bladder. Less commonly, infection reaches the kidney (pyelonephritis).

Common risk factors

• Female anatomy (shorter urethra, closer to rectum)
• Sexual activity ('honeymoon cystitis')
• Menopause (oestrogen deficiency alters urethral mucosa and vaginal flora)
• Urinary catheters
• Urinary tract abnormalities or obstruction (enlarged prostate, kidney stones)
• Diabetes (increases susceptibility)
• Incomplete bladder emptying
• Wiping back to front after defecation

Symptoms

• Burning or pain when urinating (dysuria)
• Urgent and frequent need to urinate
• Passing small amounts of urine despite strong urge
• Cloudy, dark, or foul-smelling urine
• Lower abdominal pain or pelvic pressure
• Blood in urine (haematuria)
• Pyelonephritis (kidney infection): back or flank pain, high fever, rigors, nausea, vomiting

When to see a doctor

See a doctor for UTI symptoms with back pain, fever, or rigors (suggests kidney infection — needs prompt antibiotics). Always assess UTI in men, pregnant women, children, people with catheters, or immunocompromised. Women under 65 with typical uncomplicated UTI can be treated empirically.

Diagnosis

Urine dipstick for nitrites and leucocytes. Mid-stream urine culture confirms the organism and sensitivity before antibiotics (important for recurrent UTI). Blood cultures for pyelonephritis.

Treatments

Self-care and lifestyle

• Drink adequate fluids throughout the day (6 to 8 glasses)
• Urinate promptly when you need to — do not delay
• Urinate after sexual intercourse
• Wipe from front to back after using the toilet
• Consider D-mannose (a sugar that prevents E. coli adhesion to the bladder wall) as a supplement — modest evidence for UTI prevention

Prevention

Adequate hydration, urinating regularly, post-coital urination, front-to-back wiping, and vaginal oestrogen cream for post-menopausal women (normalises local flora) reduce recurrent UTI risk. Cranberry products have limited but existing evidence for prevention.