Practical Guide to Urinary Infection in Children

1. Diagnosis of Urinary Infection in Children

Symptoms

  • Infants and Preschoolers: Fever without apparent focus, irritability, poor weight gain, vomiting, diarrhea, refusal of food.
  • Older Children: Dysuria, frequency, urinary urgency, suprapubic or lumbar pain, new-onset incontinence, fever.

Physical examination

  • Evaluate signs of sepsis in infants.
  • Abdominal palpation for pain or masses.
  • Evaluation of external genitalia.

Laboratory Tests

  • Urinalysis and Reactive Strip:
    • Positive nitrites (high specificity, low sensitivity).
    • Positive leukocyte esterase (indicates pyuria).
  • Urine culture (gold standard):
    • Collection Method: It's crucial. Prefer bladder catheterization or suprapubic puncture in infants without sphincter control. Collection bag only if negative.
    • Positivity Criteria:
      • Suprapubic puncture: Any growth.
      • Bladder catheterization: Greater than or equal to 5 x 10^4 CFU/mL.
      • Medium stream (older children): Greater than or equal to 10^5 CFU/mL of a single pathogen.

2. Treatment of Urinary Infection in Children

Antibiotic Choice

  • Initial Empirical: Based on patient age, local resistance patterns, and route of administration.
  • Adjustment: Once the urine culture antibiogram is available.
  • Infants and Fever: Consider initial intravenous treatment if there are signs of toxicity or difficulty with oral tolerance.

Common Antibiotics and Dosage

  • 2nd/3rd generation cephalosporins: (Ex. Cefuroxime, Cefixime, Ceftriaxone) – Broad spectrum, good penetration.
  • Amoxicillin/Clavulanate: Useful if there is known susceptibility.
  • Trimethoprim-Sulfamethoxazole (TMP-SMX): If the local resistance is low.
  • Aminoglycosides: (Ex. Gentamicin) – For severe or resistant cases, IV.

Duration of Treatment

  • Cystitis (Low UTI): 3-5 days.
  • Pyelonephritis (High UTI): 7-14 days. Duration may vary depending on the pathogen and clinical response.

Follow-up

  • Evaluate clinical response in 48-72 hours.
  • Repeat post-treatment urine culture only in selected cases (e.g., recurrent UTI, known urological abnormalities).

3. Prevention and Management of Recurrence

General Measures

  • Perineal Hygiene: Cleaning from front to back in girls.
  • Regular Urination: Encourage frequent and complete urination (every 2-3 hours).
  • Management of Constipation: Constipation is a major risk factor.
  • Adequate Hydration: Increases urination frequency.

Antibiotic prophylaxis

  • Consider in selected cases:
    • Recurrent UTI (more than 2 episodes in 6 months or 3 in a year).
    • High-grade vesicoureteral reflux (VUR).
    • Obstructive urological anomalies.
  • Common Drugs: Trimethoprim-Sulfamethoxazole, Nitrofurantoin, Cephalexin (at low nocturnal doses).
  • Duration: Individualized, often for several months, with periodic reevaluations.

4. Special Considerations

Urinary Infection in Infants

  • Atypical Presentation: Fever without focus, jaundice, lethargy, poor nutrition, vomiting, irritability.
  • High risk of kidney damage if not diagnosed and treated in time.
  • Always perform urine culture by catheterization or suprapubic puncture.

Recurrent Urinary Infection

  • Defined as 2 or more episodes of pyelonephritis or febrile UTI, or 3 or more episodes of cystitis.
  • Diagnostic Study: Essential to identify underlying risk factors.

Imaging Studies

  • Kidney and Bladder Ultrasound:
    • When: After the first febrile UTI in infants and young children, or any UTI in older children with risk factors (recurrent UTI, family history, slow response to treatment).
    • Aim: Detect structural anomalies (hydronephrosis, duplication, etc.) or masses.
  • Voiding Cystourethrography (CUM):
    • When: Consider in children with abnormal renal ultrasound, previously detected vesicoureteral reflux (VUR), or atypical/recurrent UTI (if not performed before).
    • Aim: Diagnose or rule out VUR and other abnormalities of the bladder and urethra.
  • Renal scintigraphy with DMSA:
    • Aim: Evaluate kidney damage (scars) post-pyelonephritis. It is not routinely recommended for initial diagnosis.

5. Bibliographic References

  • American Academy of Pediatrics. Clinical Practice Guideline for the Diagnosis and Management of Urinary Tract Infections in Febrile Infants and Young Children. Pediatrics. 2011;128(3):595-610.
  • Subcommittee on Urinary Tract Infection, Steering Committee on Quality Improvement and Management, Roberts KB. Urinary tract infection: Clinical practice guideline for the diagnosis and management of the initial UTI in febrile infants and children 2 to 24 months of age. Pediatrics. 2011;128(3):595-610.
  • NICE guideline [NG112] Urinary tract infection in under 16s: diagnosis and management. National Institute for Health and Care Excellence. 2017.
  • Other resources and relevant publications in pediatrics.