Urinary Tract Infection (Urology) — Causes, Symptoms & Treatment Guide — Symptoms, Causes & Treatment | MyMedicPlus

A urinary tract infection (UTI) in the urological context refers predominantly to complicated UTIs — those occurring in the context of structural or functional urinary tract abnormality, male patients, hospitalised patients, immunocompromised individuals, or catheter-associated situations. While uncomplicated UTI (young, healthy, non-pregnant women) is primarily managed in primary care, complicated UTI — which carries higher risks of treatment failure, antibiotic resistance, and serious complications including pyelonephritis, urosepsis, and renal damage — requires urological assessment. The anatomy and function of the urinary tract profoundly influence the risk, pathogen profile, and management of UTI. E. coli remains the predominant causative organism (80% of community-acquired UTIs), but complicated UTIs have a broader range of pathogens — including Klebsiella, Pseudomonas aeruginosa, Enterococcus, Proteus mirabilis, and coagulase-negative staphylococci — with greater antimicrobial resistance. Catheter-associated UTIs (CAUTI) represent the most common healthcare-associated infections globally, causing significant morbidity and mortality in hospitalised patients.

E. coli accounts for 80% of community-acquired UTIs; in complicated and catheter-associated UTIs, the spectrum is broader: Klebsiella pneumoniae, Pseudomonas aeruginosa (nosocomial, antibiotic-resistant — hospital-acquired UTIs and catheter-associated UTIs), Proteus mirabilis (urease-producing — splits urea into ammonia, raises urinary pH, promotes struvite stone formation), Enterococcus faecalis (particularly healthcare-associated, in patients with prior antibiotic exposure), Staphylococcus saprophyticus (young sexually active women), and Candida species (in catheterised patients and immunocompromised). Urological risk factors for complicated UTI: urinary obstruction (benign prostatic hyperplasia — the most common cause of complicated UTI in older men; urethral strictures; bilateral ureteric obstruction), vesicoureteric reflux (primary VUR — congenital; secondary VUR — from outlet obstruction), neurogenic bladder (spinal cord injury, multiple sclerosis, Parkinson's disease — causing incomplete bladder emptying), urinary diversion (ileal conduit, neobladder), urinary tract calculi (stones harbour bacteria and prevent antibiotic penetration), urinary catheters (biofilm formation within 24-48 hours of catheterisation — creates a protected bacterial reservoir), renal transplant recipients (immunosuppression, anatomical abnormalities), and diabetes mellitus (increased susceptibility, glucose in urine, and autonomic neuropathy causing urinary retention).

Lower UTI (bladder/urethra): dysuria (painful urination), urinary frequency and urgency, suprapubic discomfort, haematuria (blood in urine), turbid urine, and in men — urethral discharge if associated with urethritis. Prostatitis (bacterial — acute and chronic): perineal pain and pressure, dysuria, frequency, obstructive voiding symptoms, and in acute bacterial prostatitis — fever, rigors, and an exquisitely tender, boggy prostate on rectal examination. Acute bacterial prostatitis may progress to prostatic abscess if not treated promptly. Upper UTI (pyelonephritis): fever (above 38°C), rigors, unilateral or bilateral loin (flank) pain and tenderness (costovertebral angle tenderness on examination), nausea, vomiting, and systemic illness, in addition to lower urinary tract symptoms. Urosepsis: pyelonephritis complicated by bacteraemia — sepsis criteria: altered mental status, tachycardia (above 90 bpm), tachypnoea (above 22 per minute), hypotension (systolic below 90 mmHg). Life-threatening — requires immediate hospitalisation and IV antibiotics. Catheter-associated UTI (CAUTI): diagnosed as symptomatic bacteriuria in a catheterised patient (fever, rigors, altered mental status, loin pain, or worsening haematuria) — asymptomatic bacteriuria in catheterised patients does not require treatment (except in pregnancy and before urological procedures). Obstructed infected kidney (pyonephrosis): obstruction (stone, stricture) plus infection in the collecting system — constitutes a urological emergency; the patient is severely unwell with sepsis requiring urgent percutaneous nephrostomy drainage.

Urine analysis: clean-catch mid-stream urine (MSU) or catheter specimen (CSU) for dipstick (nitrites, leucocyte esterase) and microscopy, culture, and sensitivity (MC&S). For catheterised patients — obtain a fresh sample from the sampling port after changing the catheter (do not culture from the catheter bag, which is colonised rather than infected). Significant bacteriuria: conventionally 10^5 CFU/mL of a single pathogen; in catheterised patients and symptomatic men, lower counts (10^3 CFU/mL or above) may be clinically significant. Blood tests for complicated or upper UTI: FBC (leucocytosis, neutrophilia), CRP (elevated), blood cultures (taken before antibiotics — positive in bacteraemia/sepsis), renal function (eGFR — assess acute kidney injury from obstruction or pyelonephritis), serum lactate (elevated in urosepsis). PSA: markedly elevated in acute bacterial prostatitis (avoid DRE in acute prostatitis — risk of septic spread). Imaging: renal and bladder ultrasound (RBUS) — first-line; assesses for hydronephrosis (obstruction), echogenic shadowing (renal calculi), bladder outflow obstruction (enlarged prostate, trabeculated bladder, post-void residual). CT urogram (non-contrast CT KUB): superior for calculi (detects stones as small as 1mm); identifies anatomical abnormalities. Contrast CT (IV contrast) — CT of abdomen and pelvis with contrast in septic patients: characterises the extent of pyelonephritis, identifies abscesses (perinephric, renal, prostatic), and guides drainage. Flexible cystoscopy: for recurrent UTI, haematuria with UTI, or suspected bladder pathology (tumour, stone, diverticulum). Urodynamics: for suspected neurogenic bladder contributing to recurrent UTI. Radionuclide scan (DMSA scan): for children post-pyelonephritis — identifies renal scarring from vesicoureteric reflux.

Antibiotic selection is guided by culture and sensitivity results (empirical treatment then de-escalated when culture results available) and local antibiotic resistance patterns (PHEC/UKHSA and local hospital antibiograms). Remove or address the underlying urological cause — this is as important as antibiotics. For obstruction: urgent decompression (ureteric stent or percutaneous nephrostomy for obstructed infected ureter or kidney — a urological emergency); catheter change or removal for CAUTI. Complicated lower UTI in men (likely ascending prostatitis): co-amoxiclav 625mg three times daily for 14 days, or ciprofloxacin 500mg twice daily for 14 days (quinolone — good prostatic penetration). Acute bacterial prostatitis: ciprofloxacin 500mg twice daily or levofloxacin 500mg once daily for 4-6 weeks (quinolones penetrate the prostate well); if quinolone resistance suspected — trimethoprim 200mg twice daily or co-amoxiclav. Severe acute prostatitis: hospital admission, IV ceftriaxone 1g daily, switch to oral on clinical improvement. Chronic bacterial prostatitis: 6-12 weeks of ciprofloxacin or levofloxacin; difficult to treat due to poor antibiotic prostatic penetration and biofilm formation. Pyelonephritis (community, able to take oral): ciprofloxacin 500mg twice daily for 7 days, or co-amoxiclav 625mg three times daily for 14 days; guided by sensitivity results. Severe pyelonephritis or urosepsis: hospital admission, IV access, blood cultures, urine MC&S, IV fluids, IV antibiotics (ceftriaxone 2g daily, or co-amoxiclav 1.2g three times daily, or piperacillin-tazobactam 4.5g three times daily for more resistant organisms), regular monitoring. Catheter-associated UTI (symptomatic only): remove or change catheter if possible; treat with antibiotics for 7-14 days based on culture sensitivity. Recurrent complicated UTI: address structural abnormality (stone fragmentation, stricture repair, BPH surgery), clean intermittent catheterisation (CIC) rather than indwelling catheter, prophylactic low-dose antibiotics (trimethoprim 100mg nightly, cefalexin 125mg nightly for 6 months), and discuss risk and benefit of long-term prophylaxis. ESBL-producing E. coli and MRSA complicated UTIs: require specialist infectious disease input — carbapenems (ertapenem, meropenem) for ESBL; vancomycin or linezolid for MRSA.

Pyelonephritis (ascending infection from untreated lower UTI to the kidneys — causes fever, rigors, and loin pain; requires 7-14 days of antibiotics; hospital admission for IV treatment in severe cases). Urosepsis (pyelonephritis complicated by bacteraemia — a life-threatening emergency with in-hospital mortality of 10-30% for severe sepsis; requires immediate IV antibiotics, fluid resuscitation, and intensive care input). Renal scarring and chronic kidney disease (recurrent pyelonephritis — particularly in children with vesicoureteric reflux — causes permanent renal cortical scarring in 30-60% of affected children, leading to hypertension and chronic kidney disease in adulthood). Pyonephrosis (obstruction plus infection in the renal collecting system — the kidney fills with pus; requires emergency drainage by percutaneous nephrostomy or ureteric stent within hours, alongside IV antibiotics, to prevent permanent renal loss and overwhelming sepsis). Antibiotic resistance (recurrent UTI treated with multiple courses drives selection of ESBL-producing E. coli and carbapenem-resistant organisms — severely limiting future treatment options).

Address urological risk factors: surgical treatment of BPH (alpha-blockers, 5-ARIs, or TURP) reduces post-void residual and recurrent UTI; lithotripsy (ESWL) or ureteroscopy for renal and ureteric calculi eliminates stone-related UTI; urethral stricture dilation or urethroplasty for stricture disease. Catheter management: use urinary catheters only when clinically indicated; remove as early as possible ('catheter bundle' protocol); use aseptic technique for insertion; maintain a closed drainage system; use silver alloy-coated or antibiotic-impregnated catheters for short-term catheterisation in high-risk settings (modest evidence for CAUTI reduction); avoid routine catheter irrigation unless obstruction is anticipated. For neurogenic bladder: clean intermittent catheterisation (CIC) is associated with far fewer UTIs than indwelling catheterisation — should be offered to all suitable patients. Hydration: adequate fluid intake (1.5-2 litres/day) ensures regular bladder flushing. Bladder emptying: double voiding (void, wait 2-3 minutes, void again) reduces post-void residual; bladder training. Topical vaginal oestrogen for postmenopausal women: reduces recurrent UTI by restoring Lactobacillus-dominant flora. D-mannose: 2g daily — some evidence for reducing recurrent UTI by competitively inhibiting E. coli fimbrial adhesion. Cranberry extract (36mg proanthocyanidins daily): modest evidence for prevention of recurrent uncomplicated UTI. Antibiotic stewardship in CAUTI prevention: reserving treatment for symptomatic CAUTI; treating asymptomatic bacteriuria only in pregnancy and before urological procedures — prevents emergence of resistant organisms.

Any UTI in a man requires medical assessment to investigate and treat underlying urological causes — UTIs in men are not common without a predisposing cause and should not be dismissed. Seek immediate emergency care for: features of urosepsis (fever, rigors, confusion, rapid heart rate, low blood pressure); severe loin pain with fever (possible obstructed infected kidney — a urological emergency requiring drainage within hours to prevent loss of renal function); acute urinary retention with suspected urinary infection; and acute bacterial prostatitis with severe systemic illness. See a urologist urgently for: recurrent complicated UTIs (3 or more per year), haematuria with UTI (requires cystoscopy and imaging to exclude malignancy — particularly in patients over 45), suspected prostatic abscess, and UTI in a renal transplant patient. Patients with indwelling urinary catheters and new fever, confusion, or loin pain require prompt assessment — CAUTI is a leading cause of hospital-acquired bacteraemia and sepsis. Address antibiotic resistance: patients with recurrent UTI who have been on multiple antibiotic courses should have extended urine cultures performed to identify resistant organisms and receive antibiotic stewardship advice.