Introduction

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Classification

On basis of location

1. Lower UTI
   • Cystitis
   • Prostatitis
   • Urethritis
2. Upper UTI (Pyelonephritis)

On basis of complications:

• Uncomplicated UTI
  • Normal urinary tract
  • Normal urinary function
• Complicated UTI
  • ↓ Renal function
  • Abnormal urinary tract

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Aetiology

Causative organisms

KEEPS

• Klebsiella
• E. coli (M/C, as predominant periurethral flora)
• Enterococcus, Enterobacteriaceae
• Proteus, Pseudomonas (commonly following obstruction/instrumentation)
• Staphylococcus saprophyticus, Serratia

Risk factors: Recurrent UTI (30-50% children)

Usually occurs within 3 months of the first episode

• Female sex
• Age < 6 months or elderly
• Obstructive uropathy (stagnant urine)
• Severe vesicoureteric reflux (VUR) (M/C cause of recurrent UTI in children)
• Habitual postponement of voiding (voiding dysfunction)
• Constipation
• Repeated catheterization, e.g. for neurogenic bladder
• Immunosuppression:
  • Malnutrition
  • Immunosuppressive therapy

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Clinical features

Difficult to distinguish between infection localized to the bladder (cystitis) and upper tracts (pyelonephritis)

Clinical triad:

1. Nausea/vomiting
2. Fever
3. Flank pain (Costovertebral Angle Tenderness)

Clinical types:

• Simple UTI
  • Low-grade fever
  • Dysuria, frequency and urgency
  • Absence of symptoms of complicated UTI
• Complicated UTI
  • High fever (>39°C)
  • Systemic toxicity
  • Persistent vomiting
  • Dehydration
  • Renal angle tenderness
  • ↑ creatinine 

Paediatric age-group:

• Neonates:
  • Sepsis with fever
  • Vomiting
  • Diarrhea
  • Jaundice
  • Poor weight gain
  • Lethargy
• Older infant:
  • Unexplained fever
  • Frequent micturition
  • Occasional convulsions
• Urinary obstruction:
  • Crying or straining during voiding
  • Dribbling, weak or abnormal urine stream
  • Palpable bladder

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Complications

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Diagnosis

Urine examination

• Sample:
  • Voiding
  • Children below 2 yr:
    • Suprapubic bladder aspiration or Urethral catheterization
• Significant bacteriuria
  • Colony count of > 10⁵/ml of a single species in a clean catch sample
• Asymptomatic bacteriuria
  • Significant bacteriuria in absence of symptoms

Imaging:

Following treatment of the first episode of UTI, plans are made for evaluation of the urinary tract:

• Renal ultrasonography
  • Detects hydronephrosis or anomalies of the urinary bladder
  • Can be performed even during therapy for UTI
• Micturating cystourethrogram (MCU)
  • Diagnosis and grading of VUR
  • Defines urethral and bladder anatomy
  • Can be performed 2-4 weeks after treatment of the UTI
• Dimercaptosuccinic acid (DMSA) scintigraphy
  • Detects cortical scars (regions of decreased uptake with loss of renal contours or presence of cortical thinning with decreased volume)

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Management

Infants < 3 months of age & complicated UTI

1. Parental antibiotics (48-72 hrs):
   • Cephalosporins:
     • Ceftriaxone 75-100 mg/kg/day, in 1-2 divided doses IV
     • Cefotaxime 100-150 mg/kg/day, in 2-3 divided doses IV
   • Aminoglycoside:
     • Amikacin 10-15 mg/kg/day, single dose IV or IM
     • Gentamicin 5-6 mg/kg/day, single dose IV or IM
     • Co-amoxiclav 30-35 mg/kg/day of amoxicillin, in 2 divided doses IV
2. Oral antibiotics (10-14 days):
   • Cefixime 8-10 mg/kg/day, in 2 divided doses
   • Co-amoxiclav 30-35 mg/kg/day of amoxicillin, in 2 divided doses
   • Ciprofloxacin 10-20 mg/kg/day, in 2 divided doses
   • Ofloxacin 15-20 mg/kg/day, in 2 divided doses
   • Cephalexin 50-70 mg/kg/day, in 2-3 divided doses

Older children & simple UTI

• Oral antibiotics (7-10 days)

Adolescents with cystitis:

• Oral antibiotics (72 hr)

Prophylactic antibiotics (until imaging results are obtained)

• Cotrimoxazole
• Nitrofurantoin
• Cephalexin
• Cefadroxil

Summary