For patients with suspected UTI and sepsis (urosepsis), sepsis protocols should be immediately activated. See bacterial sepsis (management pearls) for more information.
Diagnosis Overview:
This summary discusses urinary tract infection (UTI) in infants and children. UTI in neonates is addressed separately.
UTI is a general term that describes infection anywhere in the urinary system. UTI can be further subclassified by the exact location of the infection, presence or absence of symptoms, and complications. In everyday practice, these classifications are subject to significant overlap and may be difficult to clinically determine.
Definitions
- Bacteriuria – Presence of bacteria in the urine.
- Cystitis – Syndrome involving constellation of dysuria, frequency, urgency, and occasionally suprapubic tenderness; can be present in the setting of lower urinary tract inflammation in the absence of infection or urethritis.
- Acute pyelonephritis – Clinical syndrome characterized by flank pain, flank tenderness, and fever often associated with cystitis symptoms in the presence of significant bacteriuria. This triad of symptoms (flank pain, fever, and nausea / vomiting) can also be seen in noninfectious etiologies, including renal calculi and renal infarction.
- Uncomplicated UTI – UTI in a structurally and neurologically normal urinary tract.
- Complicated UTI – UTI in the presence of anatomical or functional abnormalities.
- Urosepsis – Sepsis caused by a UTI.
UTIs are a common infection in children, with an incidence of approximately 1%-2%. They occur more commonly in males during the first 3 months of life and otherwise are more common in females throughout infancy and childhood.
Symptoms
Just as in adults, UTIs present with a range of symptoms in children. Patients may present with fever, abdominal or back pain, nausea or emesis, dysuria, hematuria, and/or fatigue. Approximately 7% of undifferentiated febrile illnesses in neonates and young infants are due to UTIs.
Etiology
Bacteria are the leading cause of UTIs, with Escherichia coli comprising 80% of cases. Other gram-negative bacteria include Klebsiella, Enterobacter, Proteus, Serratia, and Citrobacter spp. Gram-positive agents including Group B Streptococcus (GBS) and Staphylococcus spp are also found. Viral and fungal organisms are rare causes of UTIs in infants and children.
Risk Factors
- Uncircumcised males, especially if younger than 3 months. Uncircumcised males have 4-8 times increased incidence of UTI over circumcised males younger than 1 year.
- Female sex at birth: Girls have 2-4 times increased incidence of UTI over circumcised males.
- First-degree relative with history of UTI.
- Anatomic or functional abnormality and resultant vesicoureteral reflux: eg, posterior urethral valves, ureteropelvic junction obstruction.
- Neurogenic bladder: spinal cord injury (ie, myelomeningocele).
- Bladder or bowel dysfunction.
- Sexual intercourse (increases UTI risk in females).
- Bladder catheterization / instrumentation.
- Constipation.
- Ascending route – In the majority of the UTIs, pathogens gain access to the urinary tract by ascending up the urethra to the bladder. Further ascent of pathogens is the cause of the majority of renal parenchymal infections. Urethral massage and sexual intercourse facilitate the first step of this process in females. Indwelling catheters facilitate ascent, and spermicides promote vaginal colonization with pathogens.
- Hematogenous route – Associated with abscess formation in the kidneys. Usually results from bacteremia with virulent pathogens such as Staphylococcus aureus, Salmonella, or possibly Candida. Infection of the kidney with gram-negative bacilli through a hematogenous route is rare in humans, although ascending pyelonephritis can lead to bacteremia in 20%-30% of cases.
Prompt treatment of UTI is paramount to minimize potential for pyelonephritis, renal abscesses, and renal scarring that can result in chronic renal injury and hypertension. If an underlying behavior or anatomic condition is identified that places the patient at increased risk for recurring UTIs, treatment of the underlying disorder is strongly advised. Risk factors for renal scarring due to UTI include delay in effective treatment, recurrent febrile UTIs, anatomic variants causing obstruction, and bladder / bowel dysfunction.
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