CUA GL 2017 Investigation and Management of Ant detected Hydronephrosis

Question 1

What is the differential for AHN?

Answer 1

Transient primary hydronephrosis > UPJO> VUR> UVJO> primary non-obstructive megaureter

Question 2

Describe APD diameter in 2nd and thrid trimester for mild, moderate and severe AHN?

Answer 2

MILD : 2nd( 4-7), 3rd(7-9)
MODERATE : (7-10), (9-15)
SEVERE : (>10), (>15)

Question 3

What are the 5 grade of SFU AHN?

Answer 3

0 = normal/resolved 
1 = pyelectasis
2 = pyelectasis and one or morre major calyceal dilatation
3 = pyelectasis with dilatation of all major calyces 
4= pyelectasis with parenchymal thinning compared to contralateral kidney

Question 4

What is megacystis ? give me the equation

Answer 4

Fetal bladder sagittal length in mm = gestational age in weeks + 2

Question 5

What percentage of patients with mild, moderate or severe AHN have pathology post op?

Answer 5

mild = 12%
moderate = 45%
Severe = 88%

Question 6

T/F: VUR rates among patients with mild, moderate, and severe prenatal HN are not significantly different.

Answer 6

TRUE

Question 7

What is considered abnormal APD in third trimester by definition?

Answer 7

> 4mm but most centers look at 7mm or more given high false positives if you use >4mm

Question 8

Other than physical exam what should you do in a baby born with AHN>

Answer 8

UA, serum creatinine for severe bilateral HN or abnormal renal echogenicity, solitary kidney

Question 9

How long should you wait before obtaining baby serum creatinine? why?

Answer 9

2 days, because before then could be maternal

Question 10

Why would you not want to do a RBUS in the first two days of life ?

Answer 10

Neonatal oliguria would lead you to underestimate HN. dont delay in cases of PUV as you need imaging right away

Question 11

When should you do your post natal RBUS?

Answer 11

Sooner for HGHN : within a week

Can wait a bit more for LGHN: a few weeks

Question 12

Describe a good VCUG

Answer 12

scout view to assess for spine abnormality/ constipation/ stones, Do not use a balloon catheter, the amount of urine removed recorded, gravity fill bladder until the first void, record bladder capacity, voiding views of urethra and post void views of the bladder. delayed images after post void if there is reflux into a dilated system. two fill void cycles will increase detection of VUR

Question 13

Describe the well tempered renogram protocol

Answer 13

hydration, bladder catheterized, timely administration of lasix,

Question 14

What can affect the results of MAG-3 renal scan?

Answer 14

poor hydration, massively dilated kidney, full bladder, dilated distal ureter

Question 15

What study should be used to assess split renal function in neonates or premature infants?

Answer 15

DMSA since it is not influenced by immature GFR

Question 16

8. A 2-month-old male infant with an antenatal history of left moderate to severe hydronephrosis has a postnatal ultrasound at 24 hours of life demonstrating mild hydronephrosis. A follow-up US at 2 months demonstrates left severe hydronephrosis. This can be explained by:
   a. intermittent changing hydronephrosis consistent with VUR.
   b. physiologic oliguria in the newborn.
   c. worsening obstruction.
   d. ureterocele disproportion.
   e. none of the above.

Answer 16

Physiologic oliguria in the newborn. It is important to keep in mind that a postnatal ultrasound examination performed within the first 48 hours of life may not yet demonstrate hydronephrosis or may underestimate the degree of hydronephrosis secondary to physiologic oliguria.

Question 17

Which infants should go on CAP ?

Answer 17

HGHN, VUR, hydroureter, ureterocele.

Question 18

What can happen if you use sulfamethaxazole or nitrofurantoin in neonates?

Answer 18

kernicterus and hemolytic anemia respectively.

Question 19

What do you do if you got a kid with SFU G3/4, APD>15mm?

Answer 19

RBUS soon( after 2 days of life) within 2 weeks for sure, VCUG, MAG-3, CAP. In absence of pathology repeat RBUS and MAG-3 in 3 months. If no improvement keep FU, UPJO would manifest by 18 months of life.

Question 20

What do you do for SFU G1/2 or APD<10mm (LGHN)?

Answer 20

First US within first month of life then another 6 months later then annual. VCUG and MAG-3 not needed unless worsening HN. FU until at least 18 months.

Question 21

What are strong indications for surgery in AHN?

Answer 21

loss of DRF>5 % on FU
worsening HN with worsening Drainage times,
flank pain or vomiting in older children with fluid intake