Case #09 Discussion:

The patient is a 17 month-old female who presents with the history of one urinary tract infection treated with antibiotics. She is now being evaluated for vesicoureteral reflux with a voiding cystourethrogram (VCUG) and a renal ultrasound. Mother does not note any family history of reflux or urinary tract abnormalities.

Possible causes for urinary tract infections in young children include vesicoureteral reflux, urinary tract obstruction, incomplete or infrequent voiding, neurogenic bladder, or sexual abuse. The studies ordered for this patient will evaluate for reflux, obstruction, or anatomic abnormalities. Indications for imaging include the following:

1. Pyelonephritis
2. First UTI in a boy of any age
3. First UTI in a girl less than 3 years
4. Second UTI in a girl older than 3
5. First UTI in a child with family history of urinary abnormality

The most common studies ordered include renal ultrasound and VCUG.

A VCUG can detect even a small amount of reflux. It should not be performed during an active infection since inflammation can cause ureteral dilatation and mimic reflux. Reflux is graded in the following manner:

• Grade 1- Ureter only
• Grade II - Ureter, renal pelvis, calyces without dilatation
• Grade III - Dilatation or tortuosity of ureter and/or dilated pelvis
• Grade IV - Shape of calyces maintained but dilated
• Grade V - Gross dilation of collecting system

The patient has bilateral grade III vesicoureteral reflux on exam.

A renal ultrasound can show size of the kidneys, hydronephrosis, scarring, calculi, or even grossly dilated ureters. Its advantages are that it is painless, there is no radiation exposure, and no contrast. It cannot give any information about renal function. It does not exclude reflux. This patient's renal ultrasound shows kidneys normal in size and without gross abnormalities.

Given this patient's history, the two exams obtained are the ones that are the most helpful in differentiating the cause. Since reflux and obstruction are the two leading causes of UTI in a child, it is helpful to rule those in or out. In this case, the patient has reflux and not an obstruction.

Figure 9. International classification of vesicoureteral reflux. Grade I, ureter only; Grade II, ureter, pelvis, calyces; no dilatation, normal calyceal fornices; Grade 111, mild or moderate dilatation and/or tortuosity of ureter, and mild or moderate dilatation of the pelvis, but no or slight blunting of the fornices; Grade IV, moderate dilatation and/or tortuosity of ureter, and mild dilatation of renal pelvis and calyces; complete obliteration of sharp angle of fornices, but maintenance of papillary impressions in majority of calyces; Grade V, gross dilatation and tortuosity of ureter; gross dilatation of renal pelvis and calyces, papillary impressions are no longer visible in majority of calyces. (Adapted from International Reflux Committee: Medical versus surgical treatment of primary vesicoureteral reflux. Pediatrics 67:392, 1981; with permission.)

Managing Pediatric Urinary Tract Infections

History:

• In infants, poor feeding, diarrhea, vomiting, fever, or strong-smelling urine; older children may have frequency, urgency, dysuria, flank pain, or new enuresis in addition; adolescents are more likely to have the "classic" adult symptoms.

Physical Exam:

• One needs to look for hypertension, abdominal tenderness or mass, CVA tenderness, palpable bladder, poor urine stream or straining to void. Also examine genitalia for irritation, trauma, vaginitis, pinworms, or sexual abuse.

Lab Studies:

• Urinalysis - nitrate +, leukocyte esterase +, heme +
• Urine cultures - >100,000 cfu in clean-catch specimen, >10,000 in suprapubic tap or catheterized specimen
• Electrolytes - look for abnormalities or acidosis
• Increased BUN - increased suspicion for parenchymal disease or hydronephrosis

Imaging Studies:

• Plan 3-6 weeks after the infection to allow for infectious inflammation to subside
• Ultrasound to evaluate kidney size and shape, hydronephrosis, and congenital anomaly
• Voiding cystourethrogram to evaluate for vesicoureteral reflux
• Radionuclide cystography (RC) can also detect reflux. It has much less anatomic detail, but less radiation exposure than VCUG, so it is often used for follow-up studies.
• Renal cortical scintigraphy is excellent for detecting tubular damage in acute pyelonephritis or scarring from recurrent infections.

Hospitalization:

• Toxic or septic patient
• Signs of urinary tract obstruction or significant underlying disease
• Patient unable to tolerate PO fluids or medications
• Infants and children <2 years old with febrile UTI
• All infants <3 months old

Complications:

• Dehydration - should be treated with IV fluids
• Febrile UTI should be treated as pyelonephritis - parenteral antibiotics
• Untreated UTI can lead to renal involvement or systemic sepsis. Long-term complications are renal parenchymal scarring, hypertension, decreased renal function, or even renal failure.

Prognosis:

• Most UTls are uncomplicated and respond to outpatient antibiotic treatment. Patients with recurrent infections and no urinary tract abnormalities should complete a 6-month course of prophylactic antibiotics. Children with known reflux should have follow-up RC scans to follow progression. Cases of documented pyelonephritis should also have a follow-up RC scan to make sure that no permanent renal damage has occurred.