Urinary Tract Infection

Bacteriuria - may be asymptomatic or symptomatic. A diagnosis based on symptoms and signs

Lower UTI = Bladder (cystitis), prostate (prostatitis) Upper UTI = Pyelonephritis (kidney/renal pelvis)

Abacterial cystitis/urethral syndrome - a diagnosis of exclusion in patients with dysuria and frequency without demonstratable infection

Causes/Factors

• Women have increased risk
• $\uparrow$ Bacterial inoculation - sexual activity, urinary or faecal incontinence, constipation
• $\uparrow$ Binding of uropathogenic bacteria - spermicide use, $\downarrow$ oestrogen
• $\downarrow$ Urine flow - dehydration, obstructed urinary tract
• $\uparrow$ Bacterial growth - Diabetes Mellitus, Immunosuppression, obstruction, stones, catheter, renal tract malformation, Pregnancy
• Catheter associated

Symptoms

• Cystitis (UTI that affects bladder) - frequency, dysuria, urgency, suprapubic pain, polyuria, haematuria

• Prostatitis (affects prostate) - pain around: perineum, rectum, scrotum, penis bladder, lower back. Fever, malaise, nausea, urinary symptoms, swollen/tender prostate

• Acute pyelonephritis (affects kidney/renal pelvis) - fever, rigor, vomiting, loin pain/tenderness, costovertebral pain, associated cystitis symptoms, septic shock

Signs

Do not rely on classical symptoms in a catharised patient

• Fever
• Abdominal or loin tenderness
• Distended bladder

Diagnostic Tests

• Urine dipstick - use in non-pregnant women. Negative dip reduces probability of UTI to <20%. No diagnostic value in catheterised sample
• Midstream specimen of urine (MSU) culture - use in pregnant women, men, children, and if fail to respond to empirical antibiotics. Catheterized sample only if septic
• Blood tests - if systemically unwell: FBC , U&Es, CRP and culture. Consider fasting glucose
• Imaging - USS and referral to urology for assessment in men with upper UTI; failure to respond to treatment; recurrent UTI; pyelonephritis; unusual organism; persistent haematuria

Management

Increase fluid intake

In non-pregnant women of $\ge$ 3 (or one severe) symptom of cystitis and no vaginal discharge, treat empirically without further tests. If discharge consider a Pelvic inflammatory disease

Lower UTI generally Trimethoprim or nitrofurantoin Upper UTI take a culture and treat initially with broad spectrum in accordance with local guidelines (eg cefuroxime, Gentamicin, Ciprofloxacin). Avoid nitrofurantoin as doesn’t achieve effective concentrations in blood

Complications/red Flags

Renal abscesses

• Perinephric - uncommon normally caused by gram - bacteria
• Intrarenal - can be associated with classic pyelonephritis