CC Nov 2015 Antenatal hydronephrosis (AHN)

echoecho's version from 2015-12-09 14:19


Question Answer
Antenatal hydronephrosis (AHN) is one of the most frequent abnormalities detected by prenatal sonography, affecting ___ to ____% of all pregnnancies?1; 4
Definition of AHN?presence of anterior-posterior renal pelvis diameter > 4 mm in the second trimester and > 7 mm in the third trimester
AHN is ______ (bilateral vs. one-sided) in 17-54% of cases?bilateral
In 50-70% of infants, antenatal AHN is transiet or idiopathic and of no clinical significance, true or false?true
List the most common pathologic diagnosis causing AHN with percentages are?1) vesicoureteral (10-40%) 2) ureteropelvic junction obstruction (10-30%) 3) ureterovesical junction obstruction (5-15%)
List less common causes of AHN?1) posterior urethral valves 2) ureteroceles
Current guideles state that AHN in the 3rd trimester requires what evaluation even if resolution occurs on subsequent prenatal ultrasounds?postnatal evolution
Detailed prenatal sonogram reports are often not available to those taking care of infants postnatally, sometimes there is only mention of a hx of prenatal AHN or "kidney problems". What should be done for these infants?evaluate them after birth
*** What id done as the first step in postnatal evaluation?sonography during the first week after birth
Although some radiologists use their own subjective interpretation, what is recommended for the sonographic assessment of postnatal AHN?a quantitative scoring system, such as 1) anterior-posterior renal pelvis diameter (the 2010 Society for FEtal Urology grading system - SFU Grading of Infant Hydronephrosis) OR 2) 2014 urinary tract dilatation classification system
High-risk infants, including those with what 3 medical conditions should be evaluated immediately - preferably at a tertiary care center?1) oligohydramnios 2) multiple congenital anomalies 3) distended / thick-walled bladders (suspicious for posterior urethral valves)
Additionally, infants with b/l severe AHN or severe AHN in a solitary kidney should be studied when?shortly after birth and followed by a pediatric urologist
Why should initial postnatal sonograms for newborns with unilateral or mild to moderate bilateral AHN should ideally be delayed until the end of the first week after birth?because US performed in the first few days of life can underestimate the presence or severity of AHN because of transient postpartum oliguria
If there are follow-up concerns, the sonogram should be done when?before hospital discharge
In both of above situations, the sonogram should be repeated at _________ month of age to assess for resolution or progression?1
Is one single normal postnatal sonogram sufficient to verify the absence of pathology in infants with antenatal AHN?no
What test has traditionally been considered an essential part of the evaluation of all newborns with AHN, given that reflux is responsible for up to 40% of cases?VCUG (voiding cystourethrogram)
LIst the disadvantages of VCUG?1) it is a traumatic procedure 2) carries the risk of UTI 3) radiation exposure
Although some experts say to continue to perform VCUGs in all patients with AHN found on postnatal sonograms, what do other experts recommend?only those with moderate to severe AHN (SFU grades 3-4) or ureteral dilatation
When is the VCUG typically performed?4-6 weeks of age (unless a lower urinary tract obstruction is suspected)
What test is the most commonly used test to evaluate patients with AHN for obstruction?Tc-MAG3 (diuretic-enhanced renal scintigraphy using technetium-99m mercaptoacetyltriglycine)
Which infants are candidates for Tc-MAG3?1) infants with moderate to severe AHN AND 2) have no bladder reflux
When is the Tc-MAG3 performed? Why?1) before 6-8 weeks of age 2) to allow for maturation of renal function and better Tc-MAG3 uptake
What condition is more common in infants with AHN?UTI
The risk of UTI correlates with what conditions?1) severity of hydronephrosis 2) presence of reflux or obstruction 3) female gender 4) uncircumcised males
Is there conclusive evidence regarding the role of antibiotic prophylaxis in the above setting?no
*** List the patient types that shoulde receive prophylaxis while awaiting evaluation?1) females 2) uncircumscised males 3) postnatal SFU grade 2 or higher AHN 4) ureterovesical junction obstrucition 5) dilated ureter
What 2 antibiotics are usually prescribed during the first few months of life?1) cephalexin (Keflex) 2) amoxicillin
Which 2 antibiotics should be used if ongoing treatment is needed?1) sulfamethoxazole / trimethoprim (Bactrim) 2) nitrofurantoin (Macrodantin)
Which 2 antibiotics should not be used due to either poor efficacy or contraindications?1) azithromycin (Zithromax) 2) ciprofloxacin (Cipro)
Parents of all AHN infants should be counseled about what risk?UTI
Explain what is the management of infants with AHN?if antenatal hydronephrosis in 3rd trimester ----> do postnatal sonogram in first week ------> UTI prophylaxis for SFU grades 2-4 or dilated ureter AND VCUG at 4-6 weeks for SFU grades 2-4 or dilated ureter ----> sonogram at 1 month -----> Scenario #1 = resolution (2 normal studies) OR Scenario #2 = SFU grades 1-2 (do sonogram q 3-6 months) OR Scenario #3 = SFU grades 3-4 (do TcMAG3 renal scan)
*** SUMMARY = List the 3 most common pathologic diagnoses causing AHN with percentages?1) vesicoureteral reflux (10-40%) 2) ureteropelvic junction obstruction (10-30%) 3) ureterovesical junction obstruction (5-15%)
*** SUMMARY = List infant conditions that should be evaluated immediately?1) high-risk infants (including those with oligohydraminios) 2) multiple congenital anomalies 3) b/l severe AHN 4) severe AHN in a solitary kidney or distended/thick-walled bladder (suspicious for posterior urethral valves)
*** SUMMARY = What prophylaxis may be indicated in some infants to decrease the risk of UTI?antibiotic