Pediatric Urinary Tract Infection
Urinary tract infection is one of the most common pediatric infections, and may cause permanent kidney damage.
- Typically UTI develop when uropathogens that have colonized the periurethral area ascend to the bladder via the urethra. From the bladder, pathogens can spread up to the urinary tract to the kidney and possibly to the blood stream (bacteremia), which is more often seen in infants younger than 2 months.
- Bacterial infections are the most common cause of UTI. E.coli is the most frequent pathogen causing 75-90% of UTIs. Other bacteria are Klebsiella, Proteus, Enterococcus, Staphylococcus, Streptococcus and Pseudomonas.
- Some of candidate genes may predispose patient to recurrence UTI and the susceptibility to UTI maybe increased by alteration of periurethral flora by antibiotic therapy, anatomic anomaly, bowel and bladder dysfunction, and constipation.
- Fungal and viral are less common but they can also cause cystitis in certain cases and with associated risk factors including the use of invasive device (peripheral and central vascular access lines, drain catheters, previous broad spectrum antibiotic use, systemic immunosuppression, neonate in NICU.
- Children 0-2 months with UTI usually do not have symptoms localized to the urinary tract; UTI is discovered as part in evaluation of neonatal sepsis.
- Neonates with UTI may have the following symptoms: fever, jaundice, poor feeding, vomiting, irritability and failure to thrive.
- Infant and children: poor feeding, fever, vomiting, abdominal pain, urine bad smell.
- Children >2years: have urinary symptoms (dysuria, urgency, frequency) with or without systemic symptoms, fever, vomiting, and abdominal pain.
- Children >6years: flank, back pain, bad urine smell, enuresis, incontinence, dysuria, urgency, and frequency.
- Renal scarring occurs in children with recurrent pyelonephritis.
CONGENITAL CAUSE FOR UTI
- Vesicouretheral reflux is the retrograde flow of urine from the bladder into the ureter and often into the renal collecting systems. 40% of child with UTI are diagnosed with VUR. Primary VUR result from a congenital abnormality of the ureterovesical junction. Secondary VUR is caused by high pressure voiding due to neuropathic bladder, and bladder outlet obstruction. VUR is a risk factor for pyelonephritis and renal injury. The diagnosis is made by VCUG and DMSA scans are used to assess renal cortical function and renal scarring. Children with VUR are managed medically or surgically (ureteral re-implantation) and suburetric endoscopic junction of various substances.
URETEROPELVIC JUNCTION OBSTRUCTION
Evaluation of children born with hydronephrosis, abdominal mass and diuresis includes renal US, and VCUG and the management is surgical repair.
It is a cyst dilation of the terminal intravesical portion of the ureter. It is diagnosed by renal US and VCUG and the treatment is surgical.
- The ureteral orifice is classified as ectopic when it lies caudal to the normal insertion of the ureter on the trigone of the bladder.
- 70% of ectopic ureter is associated with ureteral duplication. The diagnosis is made by imaging studies and the surgical management is determined by the presence or absence of ureteral duplication.
It can be caused by spinal cord based disorders such as myelomeningocele and traumatic spinal cord injuries. Secondary reflux and incomplete bladder emptying from poor bladder function increase the risk of pyelonephritis, incontinence or urinary retention. The management includes neurosurgical intervention, anticholinergic medication, and intermittent catheterization on a regular basis and long term follow-up.
POSTERIOR URETHRAL VALVES
- The most frequent cause of congenital bladder outlet obstruction.
- PUV are membranous folds within the lumen of the prostatic urethra and it only occurs in boys.
- Antenatal US show a distended bladder and bilateral hydonephrosis.
- Oligohydramnios often indicates poor fetal renal function and can lead to pulmonary hypoplasia and postnatal respiratory distress after birth.
- Clinical presentation includes sepsis, renal failure, and distended bladder.
- Boys are the less affected and can present with recurrent UTI or urinary incontinence.
- Some of these boys have VUR and renal dysplasia.
- The diagnosis is made by US, imaging studies and the treatment is placing a small feeding tube into the bladder and primary endoscopic valve ablation.
ACQUIRED CAUSES OF UTI
- Urinary stream
- Sexual abuse
- Dysfunction voiding syndrome: dysfunction of the lower urinary tract in absence of apparent organic cause
- It is made by urine analysis (microscopic and urine culture). The presence of pyuria and bacteria on urinalysis of at least 50000 colonies forming into per ml of an uropathogen from the quantitative culture of properly collected urine specimen.
- After establishing the diagnosis of UTI, certain children require additional testing to determine possible causes for their infection. This is important as eradication of UTI with antibiotics may not be possible without correction of underlying structural abnormalities. In addition the early diagnosis of anatomically based UTIs can prevent long term sequelae of persistent or recurrent infections. Imaging studies is recommended which include ultrasound, VCUG and DMSA.
URINE SPECIMEN COLLECTION
- In infant, specimen collection should be obtained by suprapubic aspiration.
- Culture of urine specimen from a sterile bag attached to the perineal area has a high false-positive rate. However, a culture of urine collected with sterile bag that shows no growth is strong evidence that UTI is absent.
ANTIBIOTIC TREATMENT AND PROPHYLAXIS
Short treatment course for acute UTI is according to the result of culture and prophylaxis for chronic conditions.