Antenatal Hydronephrosis. Definition: AP diameter renal pelvis > 4mm @ 20 wk EGA AP diameter renal pelvis > 7mm @ 30 wk EGA Incidence: 5% of pregnancies.

Antenatal Hydronephrosis

Antenatal Hydronephrosis

• Definition:AP diameter renal pelvis > 4mm @ 20 wk EGA

AP diameter renal pelvis > 7mm @ 30 wk EGA

• Incidence: 5% of pregnancies

Antenatal Hydronephrosis

• Standard work-up:– Postnatal ultrasound

• Look for– AP diameter

– Calyceal/ureteral dilation

– Renal size

– Corticomedullary differentiation

– Thinned/hyperechoic cortex

– Cortical cysts

– Ureterocele

– Ectopic ureteral insertion

• Best after first 24 hours of life/when not volume depleted

ANH: Work-up (cont.)

– VCUG• Vesicoureteral reflux• Posterior urethral valves• Ureterocele

– Antibiotics (Amoxicillin 10mg/kg/day) until VCUG done (and normal)

Is a VCUG Necessary?• Ismaili et al., Journal of Pediatrics, June 2004

– 258 pts with ANH– 81 w/u WNL– 49 uncomplicated duplication or dilation resolved– 83 with significant findings

• 27 UPJ• 23 primary VUR• 15 primary megaureter• 10 complicated duplication (ureterocele/ectopic ureter)• 3 MCDK• 2 posterior urethral valves• 2 horseshoe kidney• 1 renal dysplasia

Ismaili Article Continued

• Normal postnatal US 3% abnormal VCUG

• AP diameter 7-10mm -- 64% had significant findings

• AP diameter >10mm -- 100% had significant findings

• Recommends no VCUG if US wnl

• This is in sharp contrast to several earlier studies

Phan, et al., Pediatric Nephrology, October 2003

• 68/111 pts with ANH and AP diameter <10mm (including several wnl)

• 16 (24%) had VUR

Anderson, et al., Pediatric Nephrology, November 1997

• Postnatal renal sonogram could not predict presence of VUR in pts with AP diameter >4mm antenatally

• 9% of pts with nl postnatal US had VUR

Farhat, et al., Journal of Urology, September 2000

• 27 % of pts with VUR (w/u prompted by ANH) had a normal postnatal RBUS

Herndon, et al., Journal of Urology, September 1999

• Of pts later dx’d with VUR (as part of ANH w/u) 88% had AP diameter <10mm

• 25% had nl postnatal RBUS

• Only 26 ureters (of 112 refluxing units) dilated on RBUS

Radiology 1993

• 25% of patients with ANH and nl postnatal RBUS had VUR on VCUG

Breakdown of postnatal dx

• 60%--normal

• 25%--UPJ (includes those that require no intervention)

• 15%--VUR

• 1-2% other

• (diagnoses may overlap)

When to get an IVP/Mag 3

• More reliable results after 8-12 weeks of life

• Mag 3 nuclear renogram preferred

• Most algorithms now are based on delayed T ½ on nuclear renogram and changes in differential function

Mag 3 Nuclear Renogram with Lasix Washout

• AP diameter >10mm• After 12 weeks of life• Differential function• Drainage (measured as time to drainage

of ½ volume of renal pelvis from administration of Lasix [or peak of tracer]), but the actual image may be more revealing, depending on region of interest drawn

When to intervene

• Differential function < 40%

• Progressive decrease in differential function on sequential nuclear renograms

Onen, Jayanthi, and Koff. Journal of Urology. September 2002

• Looks at bilateral Initial evaluation: US, nuclear renogram, serum creatinine

• 13/38 kidneys required pyeloplasty—criteria: worsening hydronephrosis, decrease in relative function >10%

• Mean time to maximal improvement by US post-op 14 months in operated group

• 10 months in nonoperative group

Other Reasons for Intervention

• Symptomatic– Failure to thrive– UTI

IVP

• Megaureter

• Persistence of AP diameter >10mm, but preserved function at one year

DMSA

• Multicystic Dysplastic Kidney

• Assure that there is no function before abandoning kidney

• 42% of kidneys dx’d as MCDK kidneys antenatally are actually hydronephrosis/UPJ obstruction

Conclusions

Most diagnoses made based on a finding of prenatal hydronephrosis can be handled conservatively.

However, until we have better ways to predict who will require intervention, a complete work-up, including RBUS and VCUG is warranted in all pts with an AP renal diameter >4mm prenatally.

Urinary Tract Infections in Children

Incidence– Neonates: M > F– Thereafter: F > M

Organisms

• Enterobacteriaciae– Escherichia (80%)– Klebsiella– Enterobacter– Citrobacter– Proteus– Providencia– Morganella– Serratia– Salmonella

Other Organisms

• Pseudamonas

• Staphylococcus

• Enterobacter

Risk Factors

• Perineal colonization• Family hx• Presence of a prepuce

– 10x risk– Periurethral colonization—circ eliminates this– Adherence of P fimbriated E. coli to prepuce

• Urethral length• Urine pH (6-7 favors growth)• Urine concentration—dilute has less nutrients• Dysfunctional elimination

Risk Factors—Dysfunctional Elimination

• Residual urine

• Increased intravesical pressure

• Bladder overdistension

• Constipation – 24% day wetters– 34% night wetters

• 90% of pts with UTI and no structural anomalies had dysfunctional elimination

Not Risk Factors

• Bubble baths

• Improper wiping

Risk FactorsUpper Tract Infections

• Antigen P1 blood group receptors

• Vesicoureteral Reflux– 25-50% of patients with pyelonephritis have

VUR– Less virulent strains of E. coli can cause pyelo

inpatients with VUR

• Obstruction

• Heredity

Presentation

• Nonverbal Patient– Irritability– Poor feeding– Failure to thrive– Vomiting– Diarrhea– Fever

• Verbal Patient– Urgency– Frequency– Enuresis– Dysuria– Fever

Diagnosis

• Urine Culture is ABSOLUTELY NECESSARY

• Symptoms are not enough• History is not enough• Of patients with dysuria, urgency, frequency,

enuresis 18% had + UCX, 40% had URI (yes, respiratory infection!)

• Local symptoms could be the same with vulvitis, urethritis, dysfunctional voiding, dehydration

Urine Cultures

• Bagged specimens are only valuable when negative

• Voided, midstream catch

• Catheterized best, and necessary in the pre-potty training age, especially if there is a fever and the diagnosis of UTI is going to lead to further testing

Diagnosis

• UA– WBC 70% reliable– Bacteria on a centrifuged urine

• UTI if WBC>10/mL & UCx >50k cfu/mL• Dipstick LE 52.9%, Nitrite 31.4% sensitive• Nitrites require 4hrs of bacterial incubation

to be +• LE may give false positive after prolonged

exposure to air

Level of Infection

• Cystitis– Symptoms

• Dysuria• Frequency• Urgency• 2o enuresis• Usually no systemic symptoms

Level of Infection

• Pyelonephritis– Fever– Flank pain– Pyuria– UCx positive– Elevated serum WBC, ESR, CRP

Asymptomatic Bacteruria

• Positive urine culture• No urinary symptoms• Only 4% later progress to symptomatic

infection• The organism may be commensal and

protective to prevent infection with a more virulent organism

• In the absence of VUR, no treatment necessary, but look for voiding dysfunction

Pyelonephritis (continued

• Diagnosis: UCx and pyuria, but DMSA to be absolutely certain (in the first several days of symptoms)

• Risks from episodes of pyelo– Focal ischemia– Inflammatory changes– Renal scarring– Hypertension– Renal insufficiency

Treatment

• Lower Tract (no fever)– Treat 3-5 days– Start with TMP-SMX, nitrofurantoin or

cephalosporin– Amoxil may change gut flora and lead to

future infections with resistant organisms – FQ ok if there is no other oral agent to use

Treatment

• Pyelonephritis– Treat 10-14 days– Start with Bactrim of Cephalosporin until

culture is back– Hospitalization in severe cases

• Abscess– UCx may be negative– Parenteral abx x 10 days then 14d oral

therapy

Work-up after a UTI

• Who?– Fever or documented pyelonephritis– <5yo

• What– RBUS (prior to discharge & yes, kidneys &

bladder)– VCUG once afebrile– DMSA

• Prophylactic antibiotics until work-up

Prophylaxis

• Vesicoureteral reflux

• No Reflux, but <1yo– 30-75% recurrence in the first year

• Frequent symptomatic UTIs