Effect

of

renal

Doppler

ultrasound

on

the

detection

of

nutcracker

syndrome

in

children

with

hematuria

To

assess

the

detection

rate

of

nutcracker

syndrome

in

children

with

isolated

hematuria

renal

Doppler

ultrasound

examinations

were

routinely

performed

on

consecutive

children

-LRB-

microscopic

hematuria

and

gross

hematuria

-RRB-

Renal

Doppler

ultrasound

was

also

performed

on

healthy

normal

children

The

peak

velocity

-LRB-

PV

-RRB-

was

measured

at

the

hilar

portion

of

the

left

renal

vein

-LRB-

LRV

-RRB-

and

at

the

LRV

between

the

aorta

and

the

superior

mesenteric

artery

The

PV

at

the

aortomesenteric

portion

-LRB-

P

-RRB-

and

the

PV

ratios

of

the

LRV

-LRB-

P

-RRB-

were

significantly

higher

in

children

with

hematuria

than

in

normal

children

while

the

PV

at

the

hilar

portion

was

not

different

If

a

PV

ratio

of

the

LRV

of

at

least

-LRB-

the

cut-off

level

set

at

the

mean

SD

of

the

value

for

the

normal

children

-RRB-

was

defined

as

abnormal

cases

-LRB-

-RRB-

in

children

with

hematuria

and

no

cases

in

normal

children

were

diagnosed

as

having

nutcracker

syndrome

The

prevalence

of

nutcracker

syndrome

is

relatively

high

in

children

with

isolated

hematuria

and

the

inclusion

of

renal

Doppler

ultrasound

as

a

screening

examination

has

a

substantial

effect

on

the

detection

of

nutcracker

syndrome

Introduction

Hematuria

is

a

common

urinary

abnormality

with

a

prevalence

of

among

school-aged

children

-LSB-

-RSB-

In

South

Korea

mass

urinary

screening

was

started

in

school-aged

children

in

and

therefore

the

incidence

of

patients

with

asymptomatic

microscopic

hematuria

has

been

increasing

When

routine

diagnostic

tests

for

hematuria

are

used

approximately

of

children

with

isolated

hematuria

are

classified

as

being

idiopathic

-LSB-

-RSB-

The

prevalence

of

nutcracker

syndrome

in

children

with

hematuria

is

unknown

because

evaluation

of

nutcracker

syndrome

has

not

been

routinely

performed

in

children

with

isolated

hematuria

This

might

be

due

to

the

absence

of

both

reliable

and

easily

applicable

diagnostic

methods

in

diagnosing

nutcracker

syndrome

in

children

Recently

however

renal

Doppler

ultrasound

has

been

developed

to

diagnose

nutcracker

syndrome

and

it

is

now

possible

to

apply

this

diagnostic

method

to

children

-LSB-

-RSB-

Therefore

we

carried

out

a

prospective

study

of

routine

renal

Doppler

ultrasound

in

children

presenting

with

isolated

hematuria

at

our

Nephrology

Unit

The

main

aim

was

to

assess

the

detection

rate

of

nutcracker

syndrome

by

renal

Doppler

ultrasound

as

a

screening

examination

Methods

Patients

All

consecutive

children

with

isolated

hematuria

-LRB-

gross

and

microscopic

-RRB-

who

visited

our

Nephrology

Unit

between

January

and

December

were

routinely

offered

a

renal

Doppler

ultrasound

to

detect

cases

of

nutcracker

syndrome

in

addition

to

a

complete

blood

cell

count

electrolytes

biochemistry

coagulation

profile

serology

for

hepatitis

B

antinuclear

antibody

anti-streptococcal

O

titer

complement

and

urine

culture

urinary

calcium/creatinine

two-dimensional

ultrasonography

and

excretory

urography

Hematuria

was

defined

as

the

presence

of

at

least

five

red

blood

cells

-LRB-

RBCs

-RRB-

in

a

centrifuged

specimen

A

urine

sample

from

each

parent

and

sibling

was

examined

for

hematuria

and

a

family

history

of

urolithiasis

was

considered

positive

if

a

sibling

parent

grandparent

or

parental

sibling

had

a

history

of

renal-stone

disease

We

excluded

proteinuria

by

urinalysis

in

most

patients

but

also

collected

urine

collections

if

proteinuria

was

suspected

by

urinalysis

in

some

patients

with

gross

hematuria

We

collected

calcium

and

creatinine

if

the

urinary

calcium/creatinine

ratio

was

more

than

Hypercalciuria

was

defined

when

calcium

excretion

was

more

than

mg/kg

Children

with

a

documented

urinary

tract

infection

-LRB-

n

-RRB-

Henoch-Schoenlein

purpura

-LRB-

n

-RRB-

and

systemic

lupus

erythematosus

-LRB-

n

-RRB-

were

excluded

because

the

causes

of

hematuria

were

evident

in

these

patients

Therefore

patients

were

included

in

this

study

showed

microscopic

hematuria

on

several

examinations

-LRB-

through

mass

urinary

screening

and

through

routine

urinalysis

during

admission

due

to

other

diseases

-RRB-

and

gross

hematuria

The

hematuria

was

intermittent

in

patients

and

permanent

in

Blood

pressure

was

normal

in

all

patients

Also

age

and

sex-matched

normal

healthy

children

with

no

evidence

of

renal

disease

or

other

chronic

diseases

were

selected

for

comparison

This

study

was

approved

by

the

institutional

review

board

and

the

research

ethics

committee

of

Yonsei

Severance

Hospital

Renal

Doppler

ultrasound

Renal

Doppler

ultrasound

was

performed

at

the

first

visit

by

one

experienced

radiologist

not

knowing

whether

the

subjects

had

hematuria

or

were

control

subjects

A

HDI

sonography

system

with

to

and

to

convex

transducers

-LRB-

Philips

Ultrasound

Bothell

Wash.

-RRB-

was

used

and

the

Doppler

spectrum

could

be

successfully

obtained

in

most

cases

except

in

one

with

a

retroaortic

left

renal

vein

After

the

patients

had

fasted

for

to

h

renal

Doppler

ultrasound

was

performed

with

the

patients

in

the

supine

position

Peak

velocity

-LRB-

PV

-RRB-

was

measured

in

the

transverse

plane

at

two

points

in

the

LRV

one

at

the

lateral

portion

of

the

LRV

near

the

hilum

-LRB-

-RRB-

and

the

other

where

the

LRV

courses

between

the

aorta

and

the

superior

mesenteric

artery

-LRB-

aortomesenteric

portion

-RRB-

Doppler

spectra

of

the

LRV

at

the

hilum

were

obtained

with

the

transducer

placed

on

the

middle

of

the

upper

abdomen

Doppler

spectra

of

the

LRV

at

the

aortomesenteric

angle

were

obtained

with

the

transducer

placed

on

the

right

or

left

subcostal

area

for

keeping

the

Doppler

angle

of

the

LRV

less

than

It

was

relatively

easy

to

obtain

the

PV

at

the

hilar

portion

of

the

LRV

with

the

Doppler

angle

of

less

than

but

there

were

some

patients

in

whom

the

measurements

of

the

PV

at

or

beyond

the

aortomesenteric

portion

of

the

LRV

were

somewhat

difficult

with

the

Doppler

angle

of

The

median

Doppler

angle

was

-LRB-

range

-RRB-

at

the

hilar

portion

and

-LRB-

range

-RRB-

at

the

aortomesenteric

portion

of

the

LRV

Ratios

of

the

PV

of

the

LRV

between

the

two

portions

-LRB-

Aortomesenteric

PV/Hilar

PV

-RRB-

were

calculated

Statistical

analysis

Statistical

analysis

was

performed

with

Student

's

t-test

and

chi-square

test

using

SPSS

for

Windows

-LRB-

version

-RRB-

The

mean

SD

of

ratios

was

calculated

for

normal

controls

and

was

used

as

the

cut-off

value

for

diagnosing

nutcracker

syndrome

A

P

value

of

or

less

was

defined

as

significant

Results

Figure

shows

Doppler

images

of

a

patient

with

nutcracker

syndrome

-LRB-

a

b

-RRB-

and

a

normal

child

-LRB-

c

d

-RRB-

Color

Doppler

imaging

of

all

LRVs

showed

blood

flow

from

the

renal

hilum

to

the

aortomesenteric

portion

Fig.

Doppler

ultrasound

of

the

left

renal

vein

in

a

patient

with

nutcracker

syndrome

-LRB-

a

b

-RRB-

and

a

normal

child

-LRB-

c

d

-RRB-

-LRB-

a

-RRB-

The

peak

velocity

was

cm/s

in

the

aortomesenteric

entrapped

portion

-LRB-

b

-RRB-

The

peak

velocity

was

cm/s

in

the

hilar

portion

-LRB-

c

-RRB-

The

peak

velocity

was

cm/s

in

the

aortomesenteric

portion

-LRB-

d

-RRB-

The

peak

velocity

was

cm/s

in

the

hilar

portion

Doppler

velocimetric

findings

in

children

with

hematuria

and

the

control

subjects

are

summarized

in

Table

In

children

with

hematuria

the

median

and

were

-LRB-

range

-RRB-

cm/s

and

-LRB-

range

-RRB-

cm/s

respectively

In

normal

children

the

median

and

were

-LRB-

range

-RRB-

cm/s

and

-LRB-

range

-RRB-

cm/s

respectively

There

were

no

differences

in

the

and

ratios

between

children

with

gross

hematuria

and

those

with

microscopic

hematuria

The

median

ratio

was

-LRB-

range

-RRB-

in

children

with

hematuria

and

-LRB-

range

-RRB-

in

normal

children

The

-LRB-

P

-RRB-

and

ratios

-LRB-

P

-RRB-

were

significantly

higher

and

had

a

wider

distribution

-LRB-

Fig.

-RRB-

in

children

with

hematuria

than

in

normal

children

On

the

basis

of

these

data

we

set

the

cut-off

levels

of

the

ratios

for

diagnosing

nutcracker

syndrome

at

the

mean

SD

of

the

value

for

the

normal

children

The

calculated

cut-off

levels

were

When

these

Doppler

sonographic

diagnostic

criteria

were

applied

cases

-LRB-

-RRB-

in

children

with

hematuria

and

no

cases

in

normal

children

were

diagnosed

as

having

nutcracker

syndrome

In

the

children

with

nutcracker

syndrome

the

ratios

were

-LRB-

median

range

-RRB-

as

compared

with

-LRB-

median

range

-RRB-

in

normal

children

-LRB-

P

-RRB-

-LRB-

Tables

-RRB-

Collateral

vessels

around

the

LRV

were

observed

in

two

patients

with

nutcracker

syndrome

The

body

mass

index

was

significantly

lower

in

the

nutcracker

group

than

in

the

non-nutcracker

group

-LRB-

P

-RRB-

-LRB-

Table

-RRB-

Table

Doppler

findings

and

anthropometric

parameters

-LRB-

median

values

and

ranges

-RRB-

Gross

hematuria

-LRB-

n

-RRB-

Microhematuria

-LRB-

n

-RRB-

Total

hematuria

-LRB-

n

-RRB-

Control

-LRB-

n

-RRB-

P-valueDoppler

findings

PV

at

AM

portion

-LRB-

cm/s

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

PV

at

hilar

portion

-LRB-

cm/s

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

NS

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

PV

ratio

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

Anthropometric

findings

Height

-LRB-

cm

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

NS

Weight

-LRB-

kg

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

NS

BSA

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

NS

BMI

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

NS

Data

are

number

-LRB-

-RRB-

PV

peak

velocity

AM

aortomesenteric

BSA

body

surface

area

BMI

body

mass

index

and

NS

not

significant

-LRB-

P

-RRB-

There

were

no

differences

between

gross

and

microscopic

hematuriaFig

peak

velocity

ratios

of

the

left

renal

vein

in

children

with

gross

-LRB-

GH

-RRB-

or

microscopic

hematuria

-LRB-

MH

-RRB-

and

normal

controlsTable

Doppler

findings

and

anthropometric

parameters

in

children

with

and

without

nutcracker

syndrome

Nutcracker

group

-LRB-

PV

ratio

n

-RRB-

Non-nutcracker

group

-LRB-

PV

ratio

n

-RRB-

P-valueDoppler

findings

PV

at

AM

portion

-LRB-

cm/s

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

PV

at

hilar

portion

-LRB-

cm/s

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

Anthropometric

findings

Height

-LRB-

cm

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

Weight

-LRB-

kg

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

NS

BSA

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

NS

BMI

-LRB-

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

Median

and

rangesPV

peak

velocity

AM

aortomesenteric

BSA

body

surface

area

BMI

body

mass

index

and

NS

not

significant

-LRB-

P

-RRB-

Clinical

characteristics

and

diagnoses

of

children

with

hematuria

with

or

without

nutcracker

syndrome

are

listed

in

Table

The

median

age

and

gender

did

not

differ

between

the

two

groups

The

incidence

of

gross

hematuria

abdominal

or

flank

pain

and

a

family

history

of

urolithiasis

were

also

similar

in

both

groups

Nutcracker

syndrome

was

present

in

of

the

children

-LRB-

-RRB-

in

whom

no

other

explanation

for

hematuria

was

ascertained

and

it

was

also

combined

with

other

causes

of

hematuria

in

patients

Among

the

children

with

nutcracker

syndrome

renal

biopsy

findings

were

normal

in

three

and

one

had

IgA

nephropathy

Table

characteristics

and

diagnoses

of

children

with

hematuria

with

and

without

nutcracker

syndrome

PV

ratios

of

the

LRVNutcracker

group

-LRB-

PV

ratio

n

-RRB-

Non-nutcracker

group

-LRB-

PV

ratio

n

-RRB-

Clinical

characteristics

Age

-LRB-

years

-RRB-

-LRB-

-RRB-

-LRB-

-RRB-

Sex

-LRB-

M/F

-RRB-

Gross

hematuria

Abdominal

or

flank

Familial

history

of

diagnoses

IgA

-LRB-

-RRB-

-LRB-

-RRB-

Thin

GBM

-LRB-

-RRB-

Hereditary

nephritis

with

Proliferative

-LRB-

-RRB-

Postinfectious

Familial

Hematuria

-LRB-

-RRB-

-LRB-

-RRB-

There

were

no

differences

between

the

two

groups

-LRB-

P

-RRB-

Numbers

in

parenthesis

indicate

the

number

of

diagnoses

confirmed

by

renal

biopsy

Results

of

renal

biopsies

were

normal

The

results

of

the

diagnostic

studies

are

included

in

Table

Complete

blood

count

electrolytes

biochemistry

and

the

coagulation

profile

were

normal

in

all

patients

Positive

antinuclear

antibody

was

detected

in

patients

-LRB-

weak

positive

-RRB-

but

repeat

testing

and

anti-ds

DNA

showed

no

evidence

of

autoimmune

diseases

Serum

concentrations

were

low

-LRB-

more

than

below

the

lower

limit

of

normal

-RRB-

in

four

patients

Hypercalciuria

was

found

in

patients

-LRB-

-RRB-

Ninety-five

percent

of

the

two-dimensional

ultrasonography

and

of

the

excretory

urography

showed

no

abnormal

findings

Of

the

abnormal

ultrasounds

-LRB-

increased

echogenecity

thickened

bladder

wall

mild

dilatation

of

the

renal

pelvis

and

urolithiasis

-RRB-

and

urographic

examinations

-LRB-

duplications

of

the

ureter

aberrant

small

right

upper

calyx

and

bifid

collecting

systems

-RRB-

no

finding

was

clinically

significant

The

detection

rate

of

nutcracker

syndrome

by

renal

Doppler

ultrasound

was

highest

among

all

diagnostic

tests

for

hematuria

Table

studiesDiagnostic

studyNormal

result

-LRB-

no

of

patients

-RRB-

Abnormal

result

-LRB-

no

of

patients

-RRB-

Positive

rate

-LRB-

-RRB-

Complete

blood

and

profile21600C321241.9C421420.9Anti-streptococcal

O

B

surface

Urine

Doppler

Discussion

According

to

Stapleton

et

al.

-LSB-

-RSB-

the

cause

of

isolated

hematuria

was

defined

in

only

of

their

patients

when

routine

diagnostic

tests

for

hematuria

were

performed

However

they

found

that

idiopathic

hypercalciuria

was

the

most

common

cause

of

hematuria

with

a

prevalence

of

in

children

with

isolated

hematuria

by

the

routine

evaluation

of

urinary

calcium

excretion

Nevertheless

the

cause

of

hematuria

in

the

remaining

of

the

patients

could

not

be

explained

In

the

present

study

we

could

not

identify

the

cause

of

hematuria

in

-LRB-

-RRB-

of

the

patients

when

renal

Doppler

ultrasound

was

not

performed

but

percent

was

found

to

have

nutcracker

syndrome

by

renal

Doppler

ultrasound

Thus

nutcracker

syndrome

was

the

most

common

cause

of

isolated

hematuria

in

children

without

urinary

tract

infection

or

proteinuria

in

our

study

and

we

speculate

that

childhood

nutcracker

syndrome

might

have

been

underestimated

in

the

past

Compression

of

the

LRV

between

the

aorta

and

the

SMA

by

a

mechanism

similar

to

that

of

a

nutcracker

has

been

recognized

by

anatomists

for

about

years

-LSB-

-RSB-

However

the

prevalence

of

this

syndrome

is

unknown

in

both

children

and

adults

with

hematuria

Even

current

textbooks

of

pediatrics

rarely

describe

this

syndrome

-LSB-

-RSB-

It

is

known

that

nutcracker

syndrome

is

an

uncommon

cause

of

gross

or

microscopic

hematuria

from

non-glomerular

origin

and

may

cause

orthostatic

or

variable

degrees

of

proteinuria

-LSB-

-RSB-

Hematuria

is

believed

to

be

caused

by

LRV

hypertension

which

may

result

in

minute

rupture

of

thin-walled

collateral

veins

into

the

calyceal

fornix

-LSB-

-RSB-

Left

renal

venography

with

measurement

of

the

pressure

gradient

between

the

inferior

vena

cava

and

LRV

has

been

used

to

confirm

nutcracker

syndrome

in

selected

cases

-LSB-

-RSB-

However

this

procedure

is

invasive

time-consuming

and

therefore

not

indicated

if

there

are

no

severe

symptoms

In

addition

there

were

no

reliable

and

easily-applicable

non-invasive

diagnostic

methods

in

diagnosing

childhood

nutcracker

syndrome

in

the

past

Consequently

it

has

been

thought

that

screening

nutcracker

syndrome

in

all

children

with

hematuria

is

unnecessary

and

irrational

and

therefore

the

prevalence

of

nutcracker

syndrome

has

not

been

evaluated

Recently

however

the

introduction

of

renal

Doppler

ultrasound

with

color

flow

has

improved

functional

diagnostic

capabilities

by

showing

the

blood

flow

velocity

of

the

LRV

-LSB-

-RSB-

Compression

of

the

LRV

between

the

aorta

and

the

SMA

may

cause

an

increase

in

flow

velocity

in

the

LRV

at

the

aortomesenteric

angle

and

this

flow

can

be

measured

noninvasively

by

using

Doppler

ultrasound

Although

anatomical

definition

of

nutcracker

syndrome

is

the

compression

between

the

aorta

and

the

SMA

the

changes

-LRB-

narrowing

at

the

aortomesenteric

portion

and

dilatation

at

the

hilar

portion

-RRB-

in

diameters

of

LRV

are

variable

according

to

the

stage

of

nutcracker

syndrome

This

would

be

the

reason

that

Doppler

ultrasound

had

been

developed

to

detect

nutcracker

syndrome

in

both

adults

and

children

Kim

et

al.

-LSB-

-RSB-

first

developed

and

applied

this

Doppler

technique

to

adults

with

nutcracker

syndrome

confirmed

by

venography

because

the

measurements

of

diameters

of

the

LRV

had

not

been

satisfactory

-LSB-

-RSB-

and

it

had

been

suggested

that

dilatation

in

the

proximal

LRV

shown

at

either

ultrasonography

or

computed

tomography

might

be

a

normal

variant

in

both

children

and

adults

-LSB-

-RSB-

Takebayashi

et

al.

also

found

that

nutcracker

syndrome

can

exist

in

either

nondistended

or

distended

LRV

and

normal

flow

also

can

exist

in

distended

LRV

-LSB-

-RSB-

However

a

combination

of

different

parameters

might

improve

the

correlation

with

hematuria

-LSB-

-RSB-

According

to

the

Kim

et

al.

's

study

-LSB-

-RSB-

Doppler

sonographic

findings

were

comparable

to

venographic

findings

and

the

sensitivity

and

specificity

of

the

ratios

were

higher

than

those

of

the

ratio

of

LRV

diameters

-LRB-

sensitivity

vs.

specificity

vs.

-RRB-

in

adults

with

nutcracker

syndrome

Park

et

al.

-LSB-

-RSB-

had

also

reported

that

the

mean

ratios

in

normal

children

aged

years

were

-LRB-

range

-RRB-

which

were

similar

to

those

-LRB-

range

-RRB-

in

our

control

subjects

-LRB-

years

-RRB-

Thus

the

Doppler

sonographic

cut-off

value

for

the

ratios

in

our

study

-LRB-

-RRB-

was

similar

to

that

of

Park

et

al.

-LSB-

-RSB-

-LRB-

-RRB-

but

lower

than

that

in

adults

-LSB-

-RSB-

-LRB-

-RRB-

Kim

et

al.

-LSB-

-RSB-

reported

the

PV

at

the

hilar

portion

in

hematuric

adults

with

nutcracker

syndrome

was

significantly

lower

than

that

in

normal

adults

suggesting

compression

of

the

LRV

at

the

aortomesenteric

portion

could

change

the

flow

pattern

in

the

hilar

portion

of

the

LRV

Similarly

our

study

also

demonstrated

that

the

PV

at

the

hilar

portion

in

the

nutcracker

group

is

significantly

lower

than

that

of

the

non-nutcracker

group

suggesting

the

entrapment

of

the

LRV

might

also

influence

the

PV

at

the

hilar

portion

We

agree

with

the

previous

reports

describing

the

necessity

of

limited

evaluations

in

children

with

microscopic

hematuria

because

the

extensive

work-up

resulted

in

a

low

rate

of

positive

findings

-LSB-

-RSB-

Nevertheless

our

data

suggest

that

the

detection

rate

of

nutcracker

syndrome

by

renal

Doppler

ultrasound

was

highest

among

many

other

diagnostic

tests

Regarding

treatment

of

nutcracker

syndrome

surgery

should

be

considered

if

the

patients

have

severe

symptoms

-LSB-

-RSB-

but

it

has

been

suggested

that

childhood

nutcracker

syndrome

might

be

a

transient

phenomenon

resolving

spontaneously

with

time

by

physical

development

-LSB-

-RSB-

Therefore

renal

biopsy

should

be

delayed

in

children

with

asymptomatic

microscopic

hematuria

if

nutcracker

syndrome

is

detected

However

if

hematuria

persists

despite

the

improvement

of

Doppler

findings

renal

biopsy

might

be

necessary

to

detect

other

causes

of

hematuria

However

our

study

has

some

limitations

-LRB-

-RRB-

We

did

not

perform

left

renal

venography

because

most

of

our

patients

had

mild

renal

symptoms

such

as

asymptomatic

microscopic

hematuria

detected

through

mass

urinary

screening

It

was

felt

to

be

unethical

to

perform

such

an

invasive

procedure

in

these

patients

-LRB-

-RRB-

Renal

Doppler

ultrasound

was

performed

by

one

pediatric

radiologist

and

we

could

not

show

inter-observer

reproducibility

-LRB-

-RRB-

We

did

not

perform

the

urinary

RBC

morphology

as

a

routine

examination

However

a

current

textbook

of

pediatrics

-LSB-

-RSB-

describes

Although

urinary

RBC

morphology

may

be

normal

with

non-glomerular

bleeding

and

dysmorphic

from

glomerular

bleeding

cell

morphology

does

not

reliably

correlate

with

the

site

of

hematuria

Kim

et

al.

demonstrated

the

percentage

of

isomorphic

RBC

was

considerably

variable

-LRB-

range

-RRB-

in

patients

with

nutcracker

syndrome

confirmed

by

venography

-LSB-

-RSB-

Despite

these

limitations

our

data

suggested

that

nutcracker

syndrome

might

be

one

of

the

leading

causes

of

isolated

hematuria

during

childhood

O O B I I O O O O B I O O O B O O O O O O B I O O O O B O B I I O O O O O O O O O O O B O O O B O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O B I O O O O B I O O O O O O O B O O O O O B I I O O B I O O O O O O O O B I O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O B O O O O O O O O O O B O O O O O O O O O O O O O O B I O O O B O O O O O O B I O O O O O O O O O B O O O O O O O O O O O O O O O O O O B I O O O O O O O B I I O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O B O O O O O O O O O O O O O O O B I O B I I O O B I O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O B I I O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O B O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I B I I O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O 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nutcracker syndrome
hematuria
renal doppler ultrasound
screening examination