Urinary Tract Infections

Urinary Tract Infections

Urinary Tract Infections

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UTI Basics - Tiny Patients, Big Bugs

  • Urinary Tract Infection (UTI): Microbial invasion of urinary tract structures.
  • Significant bacteriuria criteria:
    • Suprapubic aspirate (SPA): Any gram-negative bacilli or >1,000 CFU/mL gram-positive cocci.
    • Catheter specimen: ≥104 CFU/mL (often ≥5x104 CFU/mL).
    • Clean-catch midstream urine (toilet-trained child): ≥105 CFU/mL of a single uropathogen.
  • Common Risk Factors:
    • Age <1 year (esp. uncircumcised males <3 months, then ↑ female incidence).
    • Vesicoureteral reflux (VUR).
    • Posterior urethral valves (PUV).
    • Neurogenic bladder, dysfunctional voiding.
    • Constipation.
  • Etiology:

    E. coli is the most common uropathogen, accounting for ~80-90% of pediatric UTIs.

    • Others: Klebsiella, Proteus, Enterococcus, S. saprophyticus (adolescent females).

Symptom Spotting - Age Matters

  • Neonates (<1 month):
    • Non-specific: fever, hypothermia, poor feeding, vomiting
    • Lethargy, jaundice, irritability, poor weight gain
    • Sepsis-like picture, abdominal distension
  • Infants (1 month - 2 years):
    • Fever (often sole symptom), irritability, crying on micturition
    • Poor feeding, vomiting, diarrhea, abdominal pain/distension
    • Strong/foul-smelling urine

    ⭐ Unexplained fever is the most common presentation of UTI in infants and young children (<2 years).

  • Preschoolers (2-5 years):
    • Classic lower UTI: dysuria, urgency, frequency, hesitancy
    • New-onset incontinence (enuresis), suprapubic pain
    • Foul-smelling urine, hematuria, fever, vomiting
  • School-aged Children & Adolescents (>5 years):
    • Cystitis: dysuria, urgency, frequency, suprapubic pain, incontinence
    • Pyelonephritis: flank/loin pain, CVA tenderness, high fever, chills, malaise

Diagnosis Deep Dive - Labs & Scans

  • Urinalysis (UA): Rapid screen.
    • Positive: Pyuria (>5 WBCs/hpf or +Leukocyte Esterase), Nitrites (+ for Gram-neg, e.g., E.coli).
    • Microscopy: Bacteriuria, WBC casts (suggest pyelonephritis).
  • Urine Culture (Gold Standard): Essential for diagnosis & sensitivity.
    • Clean catch (mid-stream): ≥10^5 CFU/mL (single organism).
    • Catheter specimen: ≥5 x 10^4 CFU/mL.
    • Suprapubic Aspiration (SPA): Any Gram-neg growth; ≥10^3 CFU/mL Gram-pos. (Most sterile sample).
  • Blood Tests (if ill, <3 months, or suspected pyelonephritis): CBC (leukocytosis), CRP/ESR (↑inflammation), Blood Culture, Renal Function Tests (RFTs).

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  • Imaging Protocol:
> ⭐ For a child <**2** years with a first febrile UTI, a renal and bladder **ultrasound (RBUS)** should be performed.
  • RBUS: Initial scan. Detects renal size, hydronephrosis, abscess, gross anomalies.
  • VCUG (MCU): Gold standard for Vesicoureteral Reflux (VUR) diagnosis and grading.
  • DMSA Scan: Most sensitive for acute pyelonephritis & permanent renal cortical scarring; perform 4-6 months post-UTI to assess permanent damage.

Treatment & Guard - UTI Combat

  • Goals: Eradicate infection, prevent renal damage & recurrence.
  • Management:
    • Cystitis (Afebrile): Oral Abx (Co-trimoxazole, Nitrofurantoin) for 3-7 days.
    • Pyelonephritis (Febrile):
      • Oral intake OK: Oral Abx (Cefixime) for 7-14 days.
      • Toxic/<3mo/Vomiting: IV Abx (Ceftriaxone), then oral. Total 7-14 days.
  • Prophylaxis: For recurrent UTI/VUR Gr III-V (Nitrofurantoin/Co-trimoxazole).
  • Supportive: Hydration, timed voiding. Imaging (USG, MCU/DMSA) as indicated.

⭐ Oral antibiotics are as effective as parenteral antibiotics for febrile UTIs in children who are non-toxic and can tolerate oral intake; typical duration for pyelonephritis is 7-14 days.

High‑Yield Points - ⚡ Biggest Takeaways

  • E. coli is the most common pathogen in pediatric UTIs.
  • Urine culture is gold standard for diagnosis; suprapubic aspirate is preferred in infants.
  • Febrile UTI in infants (<2 years) requires renal ultrasound; consider MCU/VCUG for VUR.
  • Vesicoureteral reflux (VUR) is a key risk factor for recurrent UTIs and renal scarring.
  • Prompt antibiotics are vital to prevent long-term renal damage.
  • DMSA scan best detects renal scars and acute pyelonephritis_._

Practice Questions: Urinary Tract Infections

Test your understanding with these related questions

A 25 year old female, presents to the clinic with dysuria, urinary frequency and urgency. After a laboratory workup a diagnosis of cystitis is made. Which is the first line drug for the treatment for this patient?

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Flashcards: Urinary Tract Infections

1/9

_____ stones are a rare form of nephrolithiasis, most commonly seen in children (age group)

TAP TO REVEAL ANSWER

_____ stones are a rare form of nephrolithiasis, most commonly seen in children (age group)

Cystine

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