Define Urinary Tract Infection & Vesicoureteric Reflux. Describe its aetiology, clinical features, diagnosis and investigations.

Definition

• A urinary tract infection (UTI) is significant bacterial growth in the urinary tract with compatible symptoms.
• It may involve the lower tract (cystitis) or the upper tract (pyelonephritis).
• UTIs are important in children because they may signal an underlying anomaly and can cause renal scarring.

Etiology

• Escherichia coli is the commonest organism (> 80%).
• Others — Klebsiella, Proteus (associated with stones), Enterococcus, Pseudomonas, and, in neonates, Group B streptococcus.
• Routes — mostly ascending; haematogenous in neonates.

Clinical Features (age-dependent)

• Neonates & infants — non-specific: fever, poor feeding, vomiting, irritability, prolonged jaundice, failure to thrive, or sepsis. UTI must be excluded in any febrile infant without a focus.
• Older children — dysuria, frequency, urgency, suprapubic pain (cystitis); fever, loin pain and vomiting (pyelonephritis).

Diagnosis

• Urine culture is the gold standard — significant growth depends on the collection method: clean-catch/midstream, catheter, or suprapubic aspiration (any growth) in young infants.
• Urinalysis — pyuria, positive nitrites and leukocyte esterase, and bacteria on microscopy support the diagnosis pending culture.
• Collect the sample before starting antibiotics.

Vesicoureteric Reflux (vur)

• VUR is the retrograde flow of urine from the bladder up the ureter (± into the kidney), due to an incompetent vesicoureteric junction.
• It predisposes to pyelonephritis and renal scarring (reflux nephropathy), which can lead to hypertension and CKD.
• Graded I–V by severity (I = ureter only; V = gross dilatation and tortuosity with clubbed calyces).

Imaging Investigations

Management

• Prompt antibiotics after sending culture — oral for older children with cystitis; IV antibiotics for young infants, toxic children or pyelonephritis, then oral.
• Ensure adequate hydration; treat constipation and voiding dysfunction.
• VUR — antibiotic prophylaxis for high-grade reflux/recurrent UTIs; surgery (reimplantation)/endoscopic correction for high-grade or breakthrough infections.
• Advise on hygiene, regular voiding and fluid intake.

Complications

• Renal scarring → hypertension, proteinuria and chronic kidney disease.
• Recurrent infections; urosepsis in young infants; renal/perinephric abscess.

Risk Factors

• Female sex; uncircumcised boys in infancy; poor perineal hygiene.
• Constipation and dysfunctional voiding; vesicoureteric reflux and obstructive uropathy.
• Incomplete bladder emptying; sexual activity in adolescents.

Which Children to Image

• All young children (< 2 years) with a first febrile UTI, and any child with an atypical or recurrent UTI.
• Ultrasound for all; MCU and DMSA guided by age, severity and ultrasound findings.

Prevention

• Treat constipation; encourage regular, complete voiding and good hydration.
• Perineal hygiene; prompt treatment of infections; antibiotic prophylaxis in selected high-grade VUR.

Classification

• Simple (lower) UTI — cystitis in an older child, systemically well.
• Complicated / atypical UTI — young infant, seriously ill, poor urine flow, raised creatinine, non-E. Coli organism, or failure to respond in 48 hours.
• Recurrent UTI — ≥ 2 upper-tract, or ≥ 3 lower-tract, infections.

Duration of Treatment

• Lower UTI/cystitis — a short oral course (3–5 days).
• Pyelonephritis/upper UTI — 7–10 (up to 14) days; switch IV to oral once improving.

Follow-up

Ensure clinical resolution, complete imaging as indicated, and monitor blood pressure and growth in children with scarring or reflux; educate the family on early recognition of recurrences.

Specimen Collection — Significant Bacteriuria

A pure growth of a single organism with pyuria strongly supports the diagnosis; mixed growth usually indicates contamination.