Definition of Complicated Urinary Tract Infection in Children
A complicated urinary tract infection (UTI) in children is defined as an infection that occurs with underlying urological abnormalities, atypical presentation, or recurrent episodes that increase the risk of renal scarring and long-term complications. 1
Specific Criteria for Complicated UTI
Atypical UTI
An atypical UTI is characterized by any of the following:
- Patient is seriously ill 1
- Poor urine flow 1
- Presence of an abdominal or bladder mass 1
- Elevated creatinine 1
- Septicemia 1
- Failure to respond to appropriate antibiotics within 48 hours 1
- Infection with non-Escherichia coli organisms 1, 2
Recurrent UTI
Recurrent UTI is defined as:
- 2 or more episodes of UTI with acute pyelonephritis/upper tract UTI, OR 1
- 1 episode of UTI with acute pyelonephritis/upper tract UTI plus 1 or more episodes of UTI with cystitis/lower tract UTI, OR 1
- 3 or more episodes of UTI with cystitis/lower tract UTI 1
Anatomical and Functional Considerations
- Presence of vesicoureteral reflux (VUR) 1, 2
- Urinary tract anomalies or obstructive uropathy 3, 4
- Neurogenic bladder 3
- Bladder-bowel dysfunction in toilet-trained children 2, 4
Clinical Implications of Complicated UTI
Upper vs. Lower Tract Involvement
- Upper tract refers to kidneys and ureters 1
- Lower tract is distal to the ureters 1
- Pyelonephritis (upper tract infection) presents with systemic symptoms such as high fever, malaise, vomiting, abdominal or flank pain, and tenderness 1, 5
- Cystitis (lower tract infection) presents with localized symptoms of frequency, urgency, fever, and dysuria 1, 5
Risk Factors for Complications
- Age less than 2 months (higher risk of bacteremia and urinary anomalies) 1
- Male gender in early infancy 1
- Concomitant bacteremia (occurs in 4-36.4% of cases) 1
- Renal scarring (occurs in approximately 15% of children after first UTI episode) 1
Management Considerations for Complicated UTI
Diagnostic Approach
- Proper urine collection techniques are essential (catheterization or suprapubic aspiration in non-toilet-trained children) 3, 4
- Ultrasound of the urinary tract should be performed to exclude obstructive uropathy 3, 4
- Children under 2 years should be investigated after first febrile UTI 3
- Voiding cystourethrography may be indicated for recurrent or atypical UTIs 1, 3
Treatment Approach
- Antibiotic treatment for 7-14 days for complicated UTI 2, 5
- Oral antibiotics may be used if the child is not seriously ill and can tolerate the medication 3
- Antibacterial prophylaxis may be beneficial in certain cases 4, 6
Long-term Implications
Potential Complications
- Renal scarring leading to hypertension and chronic renal failure 1, 6
- Proteinuria with or without focal segmental glomerulosclerosis 6
- Pregnancy-related complications later in life 6