MANAGEMENT OF URINARY TRACT INFECTION (UTI)

DEFINITION

CLASSIFICATION

ETIOLOGY

• Escherichia coli — most common (80–85% of community UTIs)
• Staphylococcus saprophyticus (young sexually active women)
• Klebsiella pneumoniae
• Proteus mirabilis (associated with struvite stones)
• Enterococcus faecalis
• Pseudomonas aeruginosa (hospital-acquired / catheter-associated)

CLINICAL FEATURES

• Dysuria, frequency, urgency, nocturia
• Suprapubic pain/tenderness
• Cloudy, foul-smelling urine ± haematuria
• No fever/systemic features

• High-grade fever with chills and rigors
• Flank pain / costovertebral angle (CVA) tenderness
• Nausea, vomiting
• Lower UTI symptoms may coexist
• Systemic toxicity

INVESTIGATIONS

• Positive nitrites (gram-negative bacteria)
• Leucocyte esterase (pyuria)
• High sensitivity as a screening tool

• Pyuria: >5 WBC/HPF
• Bacteriuria on Gram stain
• Haematuria may be present

• Midstream clean-catch specimen
• Significant bacteriuria: ≥10⁵ CFU/mL
• Guides targeted antibiotic therapy
• Mandatory before starting antibiotics in: complicated UTI, recurrent UTI, pregnancy, failed empirical therapy

• CBC: leukocytosis
• Serum creatinine, BUN (renal function)
• Blood culture (if sepsis suspected — positive in ~20% pyelonephritis)
• CRP/ESR (raised)

• Ultrasound abdomen/pelvis: first-line — assess for hydronephrosis, abscess, calculi
• CT scan (KUB): if no response to treatment, to exclude perinephric abscess, emphysematous pyelonephritis
• VCUG / IVP: if vesicoureteral reflux or structural anomaly suspected (especially children)
• DMSA scan: for renal scarring in children

MANAGEMENT

A. GENERAL MEASURES

• Adequate hydration (2–3 litres/day)
• Analgesics/antipyretics (paracetamol/NSAIDs) for symptom relief
• Urinary alkaliniser (potassium citrate) for dysuria relief
• Treat underlying predisposing factors (e.g., calculi, obstruction, DM control)

B. ANTIBIOTIC THERAPY

1. Uncomplicated Lower UTI (Acute Cystitis — Non-pregnant Women)

(Appropriate Use of Short-Course Antibiotics in Common Infections — ACP Guidelines)

2. Uncomplicated Pyelonephritis (Outpatient — mild/moderate)

• Ciprofloxacin 500 mg BD × 5–7 days (oral, if susceptible)
• TMP-SMZ 160/800 mg BD × 14 days
• Oral cephalosporins (e.g., cefuroxime) for 10–14 days if quinolone-resistant

3. Severe / Hospitalised Pyelonephritis (IV therapy)

• IV Fluoroquinolone (ciprofloxacin 400 mg IV BD) OR
• IV Aminoglycoside (gentamicin 5 mg/kg/day) ± ampicillin OR
• IV Extended-spectrum cephalosporin (ceftriaxone 1–2 g IV OD) OR
• IV Piperacillin-tazobactam (for complicated/ESBL-suspected)

4. Complicated UTI

• Treat as pyelonephritis in duration and antibiotic choice
• After source control (e.g., catheter removal, relief of obstruction), may shorten to uncomplicated cystitis regimen
• Adjust based on culture sensitivity
• Duration: 7–14 days depending on clinical response

5. Catheter-Associated UTI (CAUTI)

• Remove or replace catheter whenever possible
• Treat only if symptomatic (asymptomatic bacteriuria in catheterised patients — NO treatment)
• Antibiotic choice based on urine C&S; 7-day course if prompt response, 10–14 days if delayed

C. SPECIAL SITUATIONS

UTI in Pregnancy

• Screen all pregnant women for asymptomatic bacteriuria at 12–16 weeks (urine culture)
• Must treat even if asymptomatic (risk of pyelonephritis, preterm labour, low birth weight)
• Safe antibiotics:
  • Nitrofurantoin (avoid at term — haemolytic anaemia risk)
  • Cephalexin, Cefuroxime (safe throughout)
  • Amoxicillin-clavulanate (if sensitive)
  • Avoid: fluoroquinolones, TMP-SMZ (1st trimester and near term), tetracyclines
• Duration: 7 days; follow-up culture post-treatment mandatory

UTI in Diabetics

• Increased risk of complicated UTI, fungal UTI, emphysematous pyelonephritis
• Adequate glycaemic control is essential
• Longer antibiotic courses (10–14 days); guided by C&S

Recurrent UTI (Women)

• Rule out anatomical abnormality, voiding dysfunction
• Behavioural measures: post-coital voiding, adequate hydration, wiping front-to-back, avoiding spermicides
• Antibiotic prophylaxis options:
  • Post-coital prophylaxis: single-dose nitrofurantoin 100 mg or TMP-SMZ
  • Continuous low-dose prophylaxis: nitrofurantoin 50–100 mg OD nocte × 6–12 months
  • Self-start therapy: patient-initiated 3-day course on symptom onset
• Cranberry products: modest benefit, not routinely recommended but may be tried
• Post-menopausal women: topical vaginal oestrogen reduces recurrence

COMPLICATIONS

• Perinephric abscess
• Emphysematous pyelonephritis (especially in diabetics — surgical emergency)
• Renal papillary necrosis
• Urosepsis / Septic shock
• Chronic pyelonephritis → chronic kidney disease
• Renal scarring (especially in children with VUR)
• Preterm labour (in pregnancy)

INDICATIONS FOR HOSPITAL ADMISSION

• Pyelonephritis with systemic toxicity/sepsis
• Inability to take oral medications (vomiting)
• Immunocompromised (HIV, transplant, DM)
• Pregnancy with upper UTI
• Suspected obstruction or abscess
• Failed outpatient therapy

ASYMPTOMATIC BACTERIURIA (ASB)

• Pregnant women
• Before urological procedures with mucosal bleeding risk

SUMMARY TABLE

Key Exam Points to Remember:

• Urine C&S is the gold standard — always collect before starting antibiotics in complicated cases
• Fluoroquinolones are reserved for pyelonephritis/complicated UTI — not first-line for simple cystitis
• Treat ALL bacteriuria in pregnancy, even if asymptomatic
• Do NOT treat asymptomatic bacteriuria in catheterised/elderly patients
• Emphysematous pyelonephritis in diabetics = surgical emergency