Urologic evaluation of the child

Contributors of Campbell-Walsh-Wein, 12th edition

C.D. Anthony Herndon, Rebecca S. Zee, Rachel Selekman, Hillary L. Copp, and Hans G. Pohl

History

Evaluating a child with a urologic condition is usually straightforward but can be challenging because of children’s anxiety. History and physical examination often reveal the diagnosis and allow development of a treatment plan, yet laboratory studies or imaging may be needed. It is also critical to approach the family members, who are equally anxious, with sensitivity and patience. Open expression of the provider’s awareness of their anxiety along with respecting the privacy of older children is important in establishing a trustful relationship.

History often constitutes the most important tool for establishing diagnosis and directing management. The child often provides a more accurate story than the parent. If parents are asking the child about voiding frequency, it is unlikely they know. Children are often oblivious to these issues, but do not underestimate even a younger child’s insight.

It is best to ask the historian to report their experience and observations rather than asking for a diagnosis or judgment of “normalcy.” For example, ask about frequency and consistency of stool rather than if a child is “constipated.”

Engaging the child with a nonthreatening activity or discussion facilitates relaxation during the encounter. Becoming frustrated with an anxious and uncooperative 2-year-old child will result in an unproductive, unpleasant encounter. Sometimes simply returning later helps settle the child.

Children are particularly sensitive to painful touch and temperature; therefore, use clean, warm hands. Examination should be performed at the encounter’s end to prevent the guardian from missing out on important clinical details if the child becomes upset.

Physical examination

Examining the pediatric patient ( Table 4.1 ) testicular exam

Examination should establish location, size, and texture of the gonads as well as identify pathology of the testicles and scrotum. The patient may be examined supine in frog leg position, with the legs spread apart, sitting, squatting, or standing. The examiner should stand on the contralateral side to area of concern. The nondominant hand is used to gently sweep the testicle toward the internal inguinal ring, sliding from the anterior superior iliac spine to the pubic tubercle. A lubricated glove (with soap and water) may aid the examiner.

Table 4.1

Useful Examination Tips

Clearly state area to be examined to guardian/child

Reserve examination for end of encounter

Have guardian bedside for comfort/distraction

Speak in a calm gentle voice throughout examination

Make sure hands are clean and warm

Techniques to increase intraabdominal pressure to visualize a bulge include jumping, coughing, laughing, blowing bubbles. If a bulge is not elicited on examination, photographs may be taken by family members. Hydrocele fluid (and neonatal bowel) transilluminates and may appear blue through scrotal skin.

Female perineal exam

The female genital examination should visualize the labia, introitus, urethral meatus, clitoris, and anus. The patient should be placed in a frog leg position. The labia majora should be gently pulled laterally and caudally to expose the introitus.

Assessing the neuromuscular system

The neuromuscular examination can assist with identifying causes of bladder dysfunction. Motor function and balance are assessed by observing the child walk or get on and off the examination table. Strength tests can be performed with cooperative children by having them squeeze fingers or push on provider’s hands. Sensation is assessed using cotton swabs and asking the patient to identify the sensation. Newborn and infant motor function can be slightly more challenging. Observation during the encounter includes an assessment of upper and lower extremity mobility. Newborn plantar reflex and palmar grasp reflex should be checked. In older children, knee patellar reflexes and ankle jerk reflexes may be assessed if relevant.

Laboratory testing

Urinalysis

Urinalysis can identify blood, protein, urinary casts, or infectious markers in urine. This includes gross examination for color, turbidity, and debris as well as dipstick and microscopic analyses. Urinary specific gravity usually ranges from 1.001 to 1.035 and can be indicative of hydration status and concentrating ability. Urinary pH can vary from 4.5 to 8 and is reflective of the serum pH. Blood in the urine can be detected on dipstick analysis but may also be positive in the case of myoglobinuria or hemoglobinuria. Microscopic identification of three erythrocytes per high-powered field (HPF) is diagnostic of hematuria. Proteinuria, red blood cell (RBC) casts, and brown-colored urine suggest a nephrogenic origin of hematuria. Leukocyte esterase and nitrite tests suggest bacteriuria.

Urine culture

Urine culture can indicate infection and identify the responsible organism. Clean-catch urine cultures are notoriously difficult to obtain in children without contamination. A sterile plastic bag with adhesive collar is placed over an infant’s genitalia to collect a sample but often is contaminated. If normal, it spares the child from a catheterized urine sample. 100,000 colony-forming units (CFU)/mL of organism plated within 1 hour of collection is necessary to define an infection with clean-catch method. A catheterized or suprapubic aspirate specimen should have a colony count of ≥50,000 CFU/mL to constitute an infection.

Urinary flow rate

Urinary flow rate in a toilet-trained child is obtained by having the child urinate into a chair or toilet with a flow device synced that records the volume of urine per time. This provides information on voiding patterns and bladder function. Ultrasound measurement of remaining urine defines the postvoid residual (PVR). Flow rates and PVR are useful for monitoring changes in response to therapy. Bell-shaped curves with minimal PVR are considered normal.

Flow-electromyography studies

Uroflow with electromyography of the pelvic floor (using perineal electrode pads) provides information on bladder pelvic floor coordination. The external urethral sphincter should be quiescent during voiding.

Urodynamics

Video urodynamics assesses continence, bladder stability, capacity, compliance, and sphincteric coordination. Fluoroscopy visualizes anatomy including the bladder outlet during voiding, bladder shape, and reflux into the upper tracts. This is an important study to characterize and trend storage and voiding dynamics in children with structural or neurologic conditions affecting bladder function. It aids in assessment of upper tract injury from high bladder pressures and guides therapeutic interventions. Because this test is invasive requiring catheter placement, knowledgeable and professional staff are paramount to provide a calm, relaxed environment.

Imaging ( Tables 4.2 and 4.3 )

Renal and bladder ultrasound

Prenatally, sonography visualizes the presence and quality of the renal cortex, laterality of any abnormality, the umbilical cord and anterior abdominal wall anatomy, quantity of amniotic fluid, and urine within the fetal bladder. Many urologic abnormalities are detected on anatomic ultrasound around 20 weeks of gestation. Postnatally, relative to sonography in adults, a newborn kidney’s more pronounced corticomedullary differentiation with darker medullary pyramids may be mistaken for hydronephrosis. Hydronephrosis can be underestimated in the several days of the newborn period due to dehydration. Sonography evaluates for hydronephrosis; cortical dysplasia; pelvic and renal cysts ( Table 4.4 ); renal, abdominal, and bladder masses; nephrolithiasis; infection; trauma; posterior urethral valves; ureteroceles; bladder diverticula; and bladder calculi ( Fig. 4.1 ).

Table 4.2

Comparison of Pediatric Urologic Imaging Modalities

	ULTRASOUND	X-RAY/FLUOROSCOPY ^a	COMPUTED TOMOGRAPHY ^a	MAGNETIC RESONANCE IMAGING	NUCLEAR IMAGING ^a
					RENAL SCINTIGRAPHY
					MAG3	DMSA
Uses in pediatric urology	• Renal/bladder • Hydronephrosis • Scrotal • Testicular torsion • Prenatal • Spinal Spinal dysraphism	• Bony abnormalities • Radiopaque stones • Stool burden • Genitogram • Urodynamics • Neurogenic bladder • Voiding cystourethrogram • Vesicoureteral reflux • Posterior urethral valves	• Severe blunt abdominal trauma • Nephrolithiasis • Renal artery disease	• Renal and bladder tumors • Pelvicaliectasis • Genitography • Urogenital sinus	• Renal obstruction	• Pyelonephritis and damage to renal parenchyma • Function of moieties in duplicated systems
Advantages	• Inexpensive • No sedation • Real-time images • No contrast	• Wide range of indications • Real-time images	• Available in most settings • Fast • No sedation needed	• Excellent anatomic detail • Urogram phase provides functional info	• Evaluates renal obstruction and function	• Evaluates renal scarring • Ionizing radiation
Disadvantages	• Equipment and operator dependent • Little functional information	• Ionizing radiation	• High doses of ionizing radiation	• Requires sedation in young children • Lack of widely available technology • High cost	• Ionizing radiation

DMSA, Dimercaptosuccinic acid; MAG3, mercaptuacetyltriglycine.

a Utilizes ionizing radiation, which should be minimized in at-risk pediatric population.

Table 4.3

When to perform imaging for Antenatally detected hydronephrosis

Adapted from American College of Radiology Appropriateness Criteria Antenatal Hydronephrosis.

IMAGING PROCEDURE	INITIAL NEONATAL IMAGING	NEONATAL US FINDINGS
IMAGING PROCEDURE	INITIAL NEONATAL IMAGING	NORMAL NEONATAL US	ISOLATED MILD (SFU 1-2 OR APRPD <15MM)	MALE WITH MODERATE-SEVERE (SFU 3-4 OR APRPD >15MM) OR ABNORMAL PARENCHYMA, DILATED URETER, BLADDER WALL THICKENING OR DILATED POSTERIOR URETHRA	FEMALE WITH MODERATE-SEVERE (SFU 3-4 OR APRPD >15MM) OR ABNORMAL PARENCHYMA, DILATED URETER, BLADDER WALL THICKENING	MODERATE-SEVERE (SFU 3-4 OR APRPD >15MM) WITH NO EVIDENCE OF VESICOURETERAL REFLUX ON VCUG OR CEVUS
RBUS	✓	✓	✓	✓	✓	✓
VCUG	✗	✗	+/−	✓	✓	Done
ceVUS	✗	✗	+/−	+/−	✓	Done
MAG-3 Renal Scan	✗	✗	✗	✓	✓	✓
RNC	✗	✗	✗	✗	✓	N/A

Abbreviations: RBUS=Renal and bladder ultrasound; APRPD=Anterior-posterior renal pelvic diameter; SFU=Society for Fetal Urology; VCUG=Voiding cystourethrogram; ceVUS=Contrast-enhanced voiding sonourethrogram; RNC=Radionuclide cystogram; MAG-3=mercaptoacetyltriglycine.

Table 4.4

Imaging Features of Renal Cysts

MULTICYSTIC DYSPLASTIC KIDNEY	POLYCYSTIC KIDNEY DISEASE		MULTILOCULAR CYSTIC NEPHROMA ^a	CYSTIC WILMS TUMOR ^a
MULTICYSTIC DYSPLASTIC KIDNEY	AUTOSOMAL RECESSIVE	AUTOSOMAL DOMINANT	MULTILOCULAR CYSTIC NEPHROMA ^a	CYSTIC WILMS TUMOR ^a
Unilateral	Bilateral	Bilateral	Unilateral	Unilateral or bilateral
Varying sizes; random distribution	Enlarged and homogeneously hyperechoic parenchyma	Replacement of renal parenchyma by cysts	Noncommunicating cyst of varying sizes but has more parenchymal tissue than MCDK	Noncommunicating cyst of varying sizes but has more parenchymal tissue than MCDK
Bilateral usually lethal	Can be lethal; nonlethal often with liver involvement	Usually later presentation in fourth and fifth decades	Peak incidence 4 years and adolescence	Occurs in children around 2–4 years of age