Urinary Tract Infection - SD

Introduction and Welcome

Good evening.
I'm Henrietta TLAs Rosenberg.
I'm the director of pediatric radiology at Mount Sinai
Medical Center in New York City
and I welcome you to Sono World.
I'm happy to have the chance to talk
to you this evening about urinary tract infection in the
pediatric age range.
Good evening. I'm happy to have the chance to speak
with you about the workup
of urinary tract infection in infants and children.

Learning Objectives

The learning objectives are the following.
When I'm done, you should be able to list the various causes
of urinary tract infection in pediatric patients to be able
to recognize the imaging findings in upper
and lower urinary tract infection
and to be aware of the controversies
regarding appropriate algorithms for the workup
of urinary tract infection in various age groups.
Remember that pediatric patients are not small adults.
We have to go out of our way to make our working area
kid friendly so that we will achieve cooperation.
We have to cajole them, we have to entertain them.
I highly suggest little game boys
with their favorite little movies
and games, DVDs that they can pick out to watch toys to play
with while they're waiting books to have read
to them while they're waiting and during the exams.
And you can bribe them too with lollipops, be patient,
be understanding and have lots of love
and you'll generally get the cooperation
that you are looking for given
that this is such a painless modality.

Incidence and Symptoms

Urinary tract infection is a very common problem in the
pediatric age range.
Approximately 5% of children less than six years
of age develop a urinary tract infection.
The parents may notice that the child has fever.
They may note that the urine is foul smelling that the baby
or the child has become inexplicably irritable.
A child who can express their symptomatology
and discomfort may complain of abdominal and or pelvic pain.
They may complain of back pain.
Parents may notice
that the children are developing nausea and vomiting.
They may notice in the children
who are already potty trained that there is urgency
and frequency and dysuria.
They may note hematuria.
Some children will develop incontinence and
and resis in the presence of a urinary tract infection
and yet others are failing to thrive.
And as part of the workup, it is discovered
that the child actually has chronic urinary tract infection.

Confirming Diagnosis with Urine Specimen

One should not even think about imaging a child
with a urinary tract infection
unless they've had a properly collected specimen
in an infant or a child who does not have urinary control.
Yet there must be a cath specimen.
If the child's urethra is not penetrable with a catheter,
it may rarely be necessary
to perform a supra pubic aspiration.
In patients who do have urinary control,
a clean catch midstream urine specimen is desired.
In children who have a clean catch midstream, there has
to be over a hundred thousand colony count
to make the diagnosis of urinary tract infection.
Those who have their specimen derived from catheterization
have to have over a 10,000 colony count
to diagnose urinary tract infection.
And if it's a supra pubic tap, any bacteria is consistent
with urinary tract infection.
We don't wanna subject the children to any imaging
unless there is true documentation
that they have a urinary tract infection.
Early diagnosis
and treatment is important to avoid renal damage.

Predisposing Factors

Some of the predisposing factors that we need to be aware
of in the pediatric age range include the virulence
of the infecting bacterial organism
and in particular p fria e coli.
This bug loves to adhere to the urothelial cells.
These bacteria secrete endotoxins.
When these endotoxins cross the mucosa to the muscle,
they paralyze the muscle so that there is diminished
ureteral peristalsis or none at all.
When this happens, there is slow flow in the periphery
of the ureters and the adherent bacteria are
not washed away.
This leaves the child with the risk of ascent
and reflux of bacteria
from the lower urinary tract into the collecting systems
as high as the kidneys.
Some of the uncommon organisms
that are predisposing are Klebsiella, Proteus, pseudomonas.
They are tending to be seen more in patients
who have neurogenic bladder and then enterobacter.
Other things to consider are including compromised host
natural immune defenses, children
who are on immunosuppression for various treatments
and when the feces are colonized by virulent bacteria.
Now most of the time we see urinary tract
infection in little girls.
It's easy to contaminate theus given the anatomy,
but the other group that are boys that we see
urinary tract infection in more often are the boys
who are not circumcised.
There is a 10 times the incidents of urinary tract infection
in uncircumcised males compared to
circumcised males.
Other predisposing features include
vesco ureteral reflux obstructive processes in the
urinary tract and children
who have difficulty in completely emptying their bladder
during tion.

Imaging Modalities

We have many choices in 2011 in terms of imaging modalities
for the diagnosis and follow-up of urinary tract infection.
Ultrasound and VCUG are the mainstay.
There are hospitals that prefer to use nuclear VCUG,
but in the current imaging armamentarium
that we have, using the last image hold
and very minimal fluoro
and saving images, instead of taking spot films,
we can significantly reduce the radiation exposure
with the voiding cysto urethrogram
nuclear renal scan is used when there is concern about
scarring function.
Ex expiratory urography is basically a thing of the past
and CT and MR are other options,
but they are reserved for those
patients in whom the ultrasound is inconclusive.

Ultrasound as Screening Modality

So with the ultrasound which has really become the modality
of choice for screening the children
with urinary tract infection,
we are not dependent on renal function
and we're not using ionizing radiation.
We can obtain a tremendous amount of information that serves
to triage those patients who need additional imaging.
We start with the bladder.
Remember, little children are not gonna
cooperate to hold their bladder.
They'll take one look at you
and they'll decide it's time to pee
and there goes the bladder.
So my recommendation is start with the bladder.
If the baby does void spontaneously,
you can always have the parent feed the baby while you're
doing the upper tract part of the study.
And then by the time you're done with the kidneys,
chances are the bladder will start to fill again.
So we're gonna look at the capacity, we'll measure it,
we'll look at the wall thickness.
We'll look using the bladder
as a sonic window at the distal ureters
and this is extremely important not only to look at the size
of the ureters but to see whether
or not there's a gaping ureteral vesicle junction
that may suggest reflux.
And then we can also use the bladder
as the sonic window in children who have suspicion
of a stone as an underlying cause
of the urinary tract infection.
And it really is a very nice easy way
to look at the distal UUs.
Now once the children have had the examination
of the full bladder, they should void.
Sometimes we have to encourage voiding
by putting a little warm water on their feet on their hands.
If they are still not potty trained,
sometimes we'll pour it right where they pee from
and then we get a post void
and check the kidneys as well as the bladder post void.

Kidney Assessment with Ultrasound

Now so far as the kidneys, we're going to assess the size.
It's very helpful in terms of serial sonograms
to decide if the kidneys are growing
or not, if they're scarring by looking at the contour
and looking at the echo texture,
which we'll go into detail about soon.
The collecting systems, we talked about the distal ureters,
but it's important to look at the pelvic cae systems and
whenever possible to see the ureters.
Normal ureters will not be able
to be seen in their mid portion because of all of the bowel
and the bowel gas that are in the area
where the ureter is coarse through.
But when they're dilated
and they're tortuous, as you'll see, it's quite easy
to see them with ultrasound.
And then we can also look at the urethra so
that we can determine if it looks like there is any
abnormality such as a diverticulum
or possibly a posterior urethral valve
or even a stone in the urethra.
And we're always looking for a whole variety
of anomalies which we'll go into some detail about
during this talk Always include the bladder.
As I mentioned before, it's a very important structure
to look at
because of the fact that it's going to give us a window
to the distal ureters,
but bear in mind that when the bladder is full,
the pelvic cae systems
and the ureters will be better distended
and this shouldn't be mistaken for an abnormality.
It's also important for the post void films to show
that the systems are decompressed.
Is it always a hundred percent
that the fullness is just physiologic?
No, it's not. But taken in the right context I think
that this information is helpful.

Bladder Capacity and Wall Thickness

So it's important to determine the bladder capacity
and there are two little equations that you can keep in mind
as you're doing this to determine if the child has an
appropriate capacity.
If the baby is less than one year of age,
you can take the baby's weight in kilos
and multiply it by seven to get the ml
that one would expect for that age baby
and its size, particularly if the child is over one year.
Then you take the child's age in years, add two
and multiply it by 30
and that will give you a general range of
where the bladder capacity should be in ml.
You can also estimate the bladder capacity if your
machine doesn't calculate the volume
by basically taking the length times the depth,
times the width and divided by two.
Just as a rule of thumb, a newborn baby will have a capacity
of approximately 30 to 50 ml.
A baby of a year of age will be about a hundred ml.
Five years will be about 210 years, approximately 300
and then over 10 years it'll be similar to an adult
where it will be about three to 400.
Always look at the bladder wall for its thickness
and it should be measured with the calipers.
If the bladder is really well distended,
the wall thickness should be less than
or equal to three millimeters.
If it's not distended,
the wall thickness should be less than
or equal to five millimeters.
Examine the wall, look for the trigone.
And here we can see these almost looking like little froggy
eyes that are coming up at the base of the bladder
and this is where we're going to look for the ureteral jets.
It's not a hundred percent if you see the jets
that there is no partial obstruction,
but it's important to demonstrate them to get
as much information as we can.
You can also look at the urethra in the presence of a male.
We're going to see a little prostate around the area.
On the sagittal view we see this little very slender
hypoechoic area bilaterally
that looks like a little flat bow tie
and these are the seminal vesicles.
In a little girl you'll see something that many people
until they know that this is the urethra, look at it
and think that this is a mass.
But this is how a normal female urethra appears.
This is just part of the area of the rectum,
that's the uterus and we can get images while
the children are avoiding.
If we have a question about the urethra
and here we can see that
as the child voids the urethra opens up
as the urine is passing through,
you can do that with a boy too.
This is a little one who they had
some concern about whether
or not he had an obstruction in the region of the Atu
of the urethra
and we had him in an upright position holding a urinal
and as he voided we could see
that the urethra becomes distended
and that there is no obstruction here
and he had a great stream.
My technologist will confirm that as she got quite a bath
during this procedure.
So you have to be careful. Now it's important too
to determine if the urinary tract infection is involving the
upper or the lower urinary tract
and that's why it's so important to try
to assess the anatomy
of the entire urinary tract to get clues.

Normal Kidney Appearance in Newborns

Now the normal appearance of the kidneys in a newborn baby
is different than what you're accustomed
to seeing in the adults.
In the newborn there is accentuation
of the cortico medullary differentiation.
Here are the medullary pyramids that look quite black
and they are surrounded
and interspersed between them by echogenic cortex.
The cortex is iso coic with the liver
and the spleen In a very young baby who is full term,
the increased echogenicity is due to a combination
of a few things, including the cellularity of the tufts
of the glomeruli is increased.
In the tiny baby there are more loops
of Henley in the cortex
and so over time as the kidney grows,
there will be more interstitial tissue
and the kidney ultimately will show
decreased echogenicity in the
cortex compared with the liver.
Notice that there's very little fat in a newborn kidney.
You said the renal sinus echoes.
There's just a very fine bright line around the kidney that
represents some perinephric fat.
As the kids get older, just
as in adults in most situations there will be an increase in
the amount of adipose tissue around the renal sinuses
as well as around the kidneys.
Now remember too that if it's a premature baby
because the kidney is even smaller, there will be
increased echogenicity in the cortex compared
to the adjacent liver and spleen.
So our evaluation is gonna include size, contour,
parenchymal echogenicity.
We're gonna look for scarring
and we'll look at the collecting systems.
Don't confuse the infant adrenal gland with the kidney.
Know that the appearance
of the adrenal is different than the kidney.
First of all, the adrenal is going to flank the upper pole
of the kidney and it will straddle it.
The cortex of the adrenal is rather hypoechoic.
While the medullary structures look linear
and appear quite echogenic, the adrenal gland can be up
to half the size of the kidney in a newborn
and then very quickly in the next month
will decrease in size.

Kidney Variants and Size Evaluation

Some variants that you should be aware of
as you look at the children.
First of all, there may be fetal loation.
You'll see little indentations as you get around each
of these little mounds in which are the medullary pyramids.
If these in indentations are opposite of the pyramid, then
that would be scarring.
But when you see it between,
this is just a normal variation.
Fetal loation drama dairy hump is another thing
that's often seen in the left kidney.
It's probably due to the fact
that the spleen is leaning on it so that it is
with a little bit of a different change in contour.
But notice that there's normal pyramids coming around
and into the hump of the kidney
and that's also a normal variation.
Do not confuse the normal variation
of the ranunculus with a scar.
The ranunculus is a linear density that is very bright
that we see extending from the renal sinus out
to the periphery of the kidney.
This is also known as the junctional parenchymal defect.
It is a little fibro fatty tissue that forms
during embryological life as a means for the two uls
to be fused to each other
and we see it much more easily in the right kidney.
Remember the size of the kidneys have to be evaluated
because part of the issue with urinary tract infection is
that the kidneys could become scarred
or if they have chronic reflux they may not be
growing properly.
So we're gonna look at every age where the lower limits
of normal are, what the mean is
and what the upper limits of normal so
that we can determine if the kidneys are normal for
that particular child's body habitus.
And also to determine if there's compensatory hypertrophy in
children who have a solitary kidney
or an opposite kidney that is not functioning well.
Just bear in mind that the normal size
for a newborn kidney is approximately four
to five centimeters in a full term baby.
If you happen to be looking at a premature baby,
you can take the gestational age
and extrapolate it to centimeters.
So if you have a baby who's 35 weeks gestational age,
the size of the kidney is gonna be approximately 35
millimeters or 3.5 centimeters.

Disadvantages of Ultrasound

There are some disadvantages of ultrasound
besides the operator dependence.
Some people feel that there's decreased sensitivity
for the detection of acute pyelonephritis,
but we'll talk about how we can do that later on.
Also, we can't quantitatively assess renal function,
but if we don't see cortico medullary differentiation,
that's kind of a red flag that we need
to be concerned about renal function.
Assuming it's not an extremely obese child in whom the
adipose tissue is masking our ability to be able
to see the cortico medullary differentiation,
we might Ms. Small cortical scars,
but we can look very carefully to try to avoid that.
We may miss ureteral stones if they are in ureters
that are not dilated or they're not in the distal
or very proximal part of a ureter.
And if there is a fungal infection
where there may be fungus balls
and we'll see an example of that later.
In the absence of hydronephrosis we may not be able
to distinguish the tissue texture from the
surrounding kidney.

Voiding Cystourethrogram (VCUG)

Well I just wanna take a minute
to talk about the voiding cysto urethrogram
because it is an integral part of evaluating children
who have urinary tract infection.
Most of the time they're very young babies
that will do this in and
after five years of age as we'll talk about later,
we don't usually do A-V-C-U-G
unless the ultrasound is abnormal.
And what we're doing with this test is trying
to determine if the child has vesco ureteral reflux
and any type of avoiding abnormality,
urethral abnormality as well.
So we'll get a preliminary KUB if it's a very large patient
or we'll save a spot film which is not really a film
but just saving the image from the screen.
We'll do a sterile catheterization
or if it's a boy who has a tight mosis
and we can't pull back the foreskin
to cleanse the external genitalia,
we will cleanse it without pulling it back
and then put the catheter where we believe the
urethral opening is
and do what's called a blind catheterization.
We're gonna measure the bladder capacity by determining
how much contrast we actually put in.
We're gonna look at the bladder wall for thickness
and contour and we will obtain two cycles of filling
and voiding films as we are looking for
and grading vesica ureteral reflux.
When we find it, we'll look at the urethra
and then we'll have an estimation of a post void residual.
Some children show up for A-V-C-U-G who instead
of having total visibility to the urethra little girls,
we will see what are called labial adhesions.
And in this situation it's almost like a boy who's
uncircumcised who has a tight osis
because the adhesions are not allowing the bacteria
and contamination to be able to be cleansed properly
as the parents are taking care of the baby during diapering.
And so in this situation they may recommend Premarin cream
until these adhesions are lysed
and then the child will come back for the VCUG.
So as the bladder gets larger, we're looking to see whether
or not there is vesco ureteral reflux
during the filling phase.
And then we're going to watch as the child voids
and ultimately have a post void to assess as well.
And we'll look at the urethra.
Not very much is going to be found in a female urethra
but in the boys it's a very important part of the exam.
We will in the boys get a set of images
with the catheter in place
and without the catheter in place as they're voiding just
to be sure that there are no urethral abnormalities
that might have been masked
by having the catheter in place such
as a valve or a stricture.
Be aware in little girls that as they void they can have
reflux into the vagina in this supine position
and here you can see the urethra, the vagina
and here's the little cervical dimple from
where the uterus is sitting
and here we see residual in the vagina.
Now in the boys I mentioned we're gonna do the images with
and without the catheter
and the voiding films are extremely important
because some children will only reflux when they are voiding
be aware that they could be in a child who has reflux
ipsilateral obstruction that is coexisting such
as the ureteral pelvic junction obstruction,
a primary mega ureter
or posterior urethral valve obstructing the bladder outlet.

Management of Reflux

Many children who are found
to have reflux are put on prophylactic low dose antibiotic
treatment and there is a lot
of controversy about this now in terms
of whether it should be used routinely with grade one
docs are tending not to use it at this particular time,
but it's very controversial
and you'll find physicians in different institutions
following their own inclination.
Reflux tends to occur in families so screening
of siblings is advised.
It's thought that in little girls
that there is an abnormal insertion
of the distal ureter at the ureteral vesicle junction
that is causing the reflux
and it's postulated
that the ureter is inserting at a steeper angle so
that there's less bladder musculature surrounding the ureter
to function as a sphincter.
And fortunately as the girls grow,
this abnormal angle of insertion diminishes
and spontaneous resolution of the reflux is likely to happen
with time by the time the girls are about five years of age.
So it has its natural history of resolution.
However, in boys is not the same phenomenon due
to the presence of the prostate gland.
Secondary reflux can develop due
to a diverticulum at the ureter vesicle junction.
Usually they are small but they can be quite large
and they weaken the muscle around the insertion of the
ureter so that the children
can develop reflux.
Other conditions that can predispose
to reflux are neurogenic bladder
and bladder sphincter DYS syner.

International Reflux Study Classification

The International Reflux Study classification is utilized
to determine what the grade of reflux is in the children
because of the fact
that treatment decisions will be made based
not only on the clinical findings
but on the degree of reflux
and of course the appearance of the parenchyma
of the kidneys when there is reflux just into the ureter,
that's grade one when the reflux goes all the way up into
the entire collecting system
but there's no dilatation of the ureter
or the CAEs or the pelvis.
That's grade two when there is mild to moderate dilatation
of the ureter and the pelvis
and slight cae blunting, that's grade three
when there's moderate dilatation
and tortuosity of the ureters
and the calouses are moderately dilated with blunting
of the fores of the calouses.
That's a grade four
and with five there's marked tortuosity, extreme enlargement
and basically convex calouses with total loss
of the papillary impressions.
Just to see what that looks like on A-V-C-U-G,
this is a grade one reflux.
Here's another one where it refluxed into a normal size
collecting system.
If you look closely here you'll see a little hutch
diverticulum that predisposed to reflux on the other side.
With grade three the collecting systems are more dilated
with four, they're quite dilated.
There's some loss of the papillary impressions.
There's in this particular case intrarenal reflux
and with grade five we have severe tortuosity
of the ureter with total blunting of the calouses.

Detecting Reflux with Ultrasound

Now we can look for evidence of reflux
when we are doing our ultrasound, this particular baby
has abnormal renal parenchyma.
There's some diminished cortico medullary differentiation
and there is moderate enlargement of the collecting system.
Not only the intrarenal collecting system but the ureter.
And as we trace the ureter down
to the ureterovesical junction, we see a gaping orifice
in the presence of a gaping orifice.
It is very likely that the cause of the dilatation is due
to vesco ureteral reflux
and that the reason the renal parenchyma does not look
normal is because of a reflux nephropathy.
Always look for changes in the size
of the intrarenal collecting system.
In this particular baby we saw that there was
a mild dilatation then right in front
of our eyes a few seconds later it wasn't there anymore.
But on the VCUG it was obvious
that there was grade three reflux.
Look at the size of the kidneys, make sure
that the images are taken with the same scale.
So if there is a discrepancy we're gonna be making
measurements and assessing such as in this child
where we see a smaller right kidney
and it has loss of some of the cm js,
it looks like there's thinner parenchyma
and here on the opposite side we see a perfectly normal
looking kidney child did have
right-sided vesco ureteral reflux of about a grade four.

Nuclear Medicine for Reflux

Now in terms of nuclear medicine we can use that
to determine if there is reflux.
Some places feel that this is totally appropriate in girls
because we're not really looking for urethral abnormalities
and there's a lower radiation dose.
But with a nucleus cystography,
since we are looking from a posterior view, the bladder
as it accumulates the radiopharmaceutical
and is distending can obscure the distal UUs
and so we could miss grade one vesco ureteral reflux.
We also can't use nucleus cystography
to accurately grade reflux using the international reflux
study criteria.
We can't assess the bladder sphincter DYS synergic problems.
It is thought to be useful for screening siblings of a child
with reflux and there are some centers
that are using ultrasound contrast agents to perform VCUG just
to show you the nucleus study in this patient
who has a small left kidney
and a larger, more normal looking right kidney.
Looking from behind we see that there is actually bilateral
vesco ureteral reflux.
As the bladder gets larger, the reflux gets worse
and as the child voids the refluxes even much worse
into this left kidney.
Ultimately when the bladder is empty there is just a small
residual left in the left kidney
but the right kidney has completely drained.
Here's another example with ultrasound,
we see thinning of the parenchyma.
There's a little bit of loss of the CJs,
we can trace the ureter down.
Looks a little bit almost like a GI signature,
very similar appearance to the wall where we see the mucosa
and then the muscular portion, we could see some peristalsis
as we got more distally
and then ultimately showed the distal ureter here,
this is the bladder, here's the rectum.
And then during the VCUG filling phase there was nothing
that looked like reflux.
However, once the child started voiding we could see
that there was massive vesco ureteral reflux all the way up
into the kidney with blunting of the CAEs consistent
with a grade five.
Another one had normal renal parenchyma
but had moderate dilatation of the pelvic HELOC seal system.
There is blunting.
The ureter we see the proximal end is dilated,
it's tortuous, we follow it down
through the retroperitoneum, quite dilated, quite tortuous
and we could see two
and fro peristalsis we never could see a gaping ureter
vesicle junction so we really weren't sure looking at this
whether it was reflux or whether it was a UVJ
but then the VCUG confirmed that this was massive
reflux into the left collecting system.

Treatments for Reflux

Well some of the treatments that are used,
we've already talked about low dose antibiotics.
It's usually long term suppressive medication till about
four or five years or
until vesco ureteral reflux ceases
and many urologists have felt that this is very appropriate
for low grade of reflux when there is
insufficient growth of the kidneys.
When there is thinning of the kidneys, evidence
of scarring continued recurrent urinary tract infection
then thought is given to whether
or not some type
of anti-reflux surgery is appropriate like
reimplantation of the ureters.
Also there is the possibility
of using endoscopic intravesical injection of a small amount
of a collagen like material into the bladder wall
behind the submucosal ureteral tunnel
that can serve to correct the problem of reflux.
And the agent that is often used is called dfl.
The initial studies that were done at the Boston Children's
Hospital published their results showing this gaping
ureter vesicle junction prior to the treatment with
what was an autologous chondrocyte injection that
tremendously decreased the size
of the ureteral vesicle junction.
This is what D flux looks like on an ultrasound.
We see these very solid looking mounds of moderately
koic material.
You have to be sure that you're not looking at clots
so turn the patient and make sure it's not moving.
Turn on the DOPP lip to be sure that they're not masses.
In Dr. Paul Thiel's article, they demonstrated that
when the mound on follow up appears to be bi lobe,
that can be a significant finding in terms of
an indication of continued reflux.
If the mound as on this side is round then
and it's uni lobe,
it's more likely effective in correcting the reflux.
Generally over time the volume of the mounds decreased
and there are situations at times where the treatment
with a DFL can induce hydro ureteral necrosis.
It's uncommon and it's usually self-limited.

Upper Urinary Tract Anomalies

Some of the upper urinary tract anomalies that we need
to be concerned about include ureteral pelvic junction
obstruction, ureteral duplication that may be complete
incomplete may have an associated obstructing urease seal.
Some children develop ureteral obstruction
because of primary mega ureter due to an atresia or a kink
and then there are children
with ureteral vesicle junction obstruction.
So let's look at a few examples.
Here's a chance to see an IVP an almost extinct study at
this time where we see the difference
between the right kidney that's normal after Lasix emptying.
And here's the obstruction on the left
with ultrasound we see the large renal pelvis which is the
most medial structure connecting to the dilated CAEs.
There is some thinning of the parenchyma around this
but there is some preservation
of the cortico medullary differentiation.
Remember to look at the bladder first
because looking at the upper tract we really don't know
whether there is dilatation of the distal ureter.
So if the ultrasound shows hydronephrosis
and the VCUG is normal, then one has
to assess the renal function
and may need to assess glomerular filtration
with A-D-T-P-A study or possibly tubular excretion.
Using Lasix washout to demonstrate
the quantification of renal function
with a diuretic renogram.
In the normal situation we're going to see
after the Lasix a very rapid washout.
When there's obstruction we will not see that phenomenon
but then there are some intermediate ones
that are indeterminate because of poor function or
because of dilution of the radiopharmaceutical.
Sometimes we need multimodality imaging for problem solving.
This kidney looked like it had a giant cystic structure in
the lower pole, the little fullness
of the upper pole collecting system.
Here we see that there's some contrast in this area
where the cyst was that is deviating the left upper pole
ureter, these are a little bit dilated.
Nuclear medicine showed the normal upper pole.
There was some pre Lasix radiopharmaceutical
seen in the region of the cyst and then
after Lasix we see that there is an obstruction
to this portion of the kidney.
So this patient had a duplicated collecting system
with a ureteral pelvic junction
obstruction involving the lower poly moiety.
MR is a very time consuming study and
unless there is an inconclusive ultrasound,
we generally reserve this modality for children in whom
we cannot provide enough information for
accurate therapeutic decision making.
But it certainly is an option when there are questions.
Duplex kidneys are seen in a small percent of patients
and as long as they have no symptoms
and they have no dilatation of the collecting systems,
we're not concerned.
As we can see with this voiding cysto urethrogram,
it's possible that there can be reflux into the lower pole
of the duplex collecting system
and this particular configuration known
as a drooping lily appearance
because of the fact that there is another part
of the kidney here that is not refluxing
but taking up space.
Another example with ultrasound normal upper pole we see a
dilated collecting system in the lower pole.
Very decreased depth to the renal parenchyma surrounding
this patient who turned out
to have grade five reflux.
We can see this in the same orientation as the VCUG.
There are times when we're going to be able to show
with the ultrasound that in addition to the dilatation
of the upper pole, moty will follow the ureter,
it will be dilated
and terminate as an ectopic urease seal at
the base of the bladder.
Ectopic urease seals are seen in various places.
Remember the upper pole ureter is inserting more medially
and inferiorly than where the trigone would ordinarily
have the ureter insert into so
that in little girls it could be in the bladder,
it could be in the bladder neck, it could be in the vagina.
And in fact if there isn't a ureter, a seal
and the ureter is actually draining urine.
These children who have the ureter inserting into the vagina
may present with consistently wet diapers
and incontinence in boys.
It's not a problem even if it's
inserting into the posterior urethra
because of the fact that it's proximal
to the external sphincter.
Another one masquerades is a renal cyst.
Renal cysts are very rare in children.
If we follow the ureter all the way down into the region
behind the bladder we see
that it terminates within the bladder
as a large ureter seal.
Notice the fullness of the lower poly moty.
This is due to reflux.
Sometimes the urease seals will t and we can see in this one on the initial VCUG
that there's a filling defect.
As the bladder gets bigger, the defect gets smaller
and ultimately is averting out of the bladder his
where the patient voided
and it gets larger again,
primary mega ureters can be seen.
This is usually associated
with an a dynamic distal segment of the ureter.
It's more common in boys than girls,
it's frequently bilateral Lasix pre
and post can be very helpful in deciding whether
or not there is a significant obstruction
that requires surgery.
Many of these will spontaneously regress in terms
of ureteral vesicle junction obstruction.
If we do a VCU and we don't see reflux
but we see an indentation in the area
where the ureter should be, we need to trace
that ureter very carefully.
Here's the sagittal view,
here's the kidney obviously no cortico medullary
differentiation consistent with a nephropathy.
There's dilatation
of the pelvic cae system marked dilatation
and tortuosity of the ureter which terminates
as a very narrow pointed structure consistent
with ureteral vesicle junction obstruction.

Lower Tract Anomalies

Now low tract anomalies include things like neurogenic
bladder, bladder and urethral diverticular bladder
and urethral fistula such as we may see in patients
with IMP preferred anus.
Posterior anterior urethral valves and fibrosis.
Posterior urethral valves have been shown
to be significant in causing obstructive neuropathies
and renal dysplasia.
Because of the obstruction there may be bladder wall
thickening and trabeculation.
They can be dilatation of the posterior urethra
and a utricle and there may be vesco ureteral reflux.
These children can present with a urinary tract infection
but they may also have a lower abdominal mass
because of the distended bladder.
They may have a poor urinary stream
and these boys may be incontinent.
They may have a mass because of a urin.
If they're a micro microfractures in the fores of the CAEs
they can present with urinary ascites as babies
rarely will the bladder perforate.
Typically in these boys we're going
to see a thick walled trabecula bladder
and if we angle appropriately we will see the dilatation
of the posterior urethra.
It's helpful if we can get them to void a little bit.
We can also look at the perineum
and the base of the penis to see the urethra using
that approach as well.
And then the VCUG is essential to document
that there is a dilated obstructed posterior urethra
secondary to the valve.
There's also diverticular coming off the bladder.
Typically these patients will have bilateral severe
dilatation and tortuosity of the ureters with
variable degree reflux.
This is a five. There's even intrarenal reflux,
very elongated bladder with diverticular
and the dilated posterior urethra.
This patient also had renal dysplasia associated with it
where there is bright echogenicity seen through most
of the parenchyma.
Some valves are not really significant in causing
obstruction like this.
Type three which is in the mid part of the posterior urethra
and is essentially a web.
We may be able to see the cyst like structure
that is present in patients with an anterior urethral valve,
which basically leads to the same type of obstructive
and reflux findings as we may see
with posterior urethral valve.
If it's large enough, remember that babies with osis,
the uncircumcised boys who can accumulate a huge amount
of contrast in the foreskin during the voiding phase.

Pyonephrosis and Related Findings

PY necrosis can be considered when looking at a sonogram
where there is echogenic material within the collecting
system in the presence of a bacterial or fungal infection.
This is a patient with renal dysplasia
with a posterior urethral valve and ended up with fever
and neuro sepsis in the presence of py nephrosis.
Other things can look like this including protein and blood,
although blood is usually much brighter initially
this little preemie baby you can see the hyper coic renal
parenchyma has no cortico medullary
differentiation has hydro.
And here's the little fungus ball that had been noted
with the ultrasound and confirmed with culture.
Here's another patient who had this mass in the region
of the pelvis next to the rectum behind the bladder going
sed on this we see
that it's really a dilated tubular structure
with a fluid debris level.
As we traced it superiorly,
we could see the fluid debris level
and then this huge structure that is connected to
what looks like the normal part of the kidney.
So this was basically an ectopic urease seal
with a duplicated collecting system with a totally normal
mid and lower part of the kidney,
but the patient had py necrosis and had U sepsis.
This was easily drained through a cystoscope.

Stones and Urinary Tract Infection

Stones can be associated with urinary tract infection
and it's important with the ultrasound
to look at the entire urinary tract.
CT in the pediatric age range is reserved for patients
with negative sonograms
and high clinical suspicion of calculate,
but there's really no reason to put a child who is not obese
through a ct.
We can look for dilatation of the upper tracts, the ureters,
here's the distal ureter, slightly dilated
and here's a little stone sitting right
above the ureteral vesicle junction.
Sometimes when we do CT we will get information
that's helpful in terms
of showing inflammatory changes in the perinephric space.
If there are stones in the ureters, there can be a rind
of soft tissue attenuation in the peri ureteral space,
the rim sign due to edema in the ureteral wall
and often we'll be able to use our axial coronal
and sagittals to confirm hydro ureteral necrosis.
Here's a patient who ended up with a CT scan.
He was a little bit chubby
and had a stone right at the ureteral vesicle junction.
Well there's no reason to follow this with ct.
We can use ultrasound very nicely as our baseline show.
The dilatation of the intrarenal collecting system,
this little bugger right at the distal end of the ureter
and look not only for the shadowing of the stone
but the twinkle artifact with color doppler.
Don't forget to look at the urethra.
This little boy had a urinary tract infection
and complained that he couldn't void
that he had terrible pain and really couldn't void.
We looked at his penis to try to see what it was
that was causing his problem
and sure enough there's a stone
that's shadowing sitting right in the fossa n ulis in
the glands of the penis.

Pyelonephritis

Now with pyelonephritis, children have a variety
of presenting features.
Depending upon how old they are,
the babies will often be irritable, have fever.
Older children may have flank pain,
they may have nausea and vomiting along with their fever.
Although the findings can be more challenging
In the ultrasound evaluation of acute pyelonephritis,
there are several things that we can look for
that can help us come to the conclusion as to whether
or not the kidneys are abnormal.
Sometimes we do not see any abnormalities,
but in a fluoride pyelonephritis we may see renal magaly.
We may see decrease in the cortico
medullary differentiation.
There may be focal parenchymal abnormalities.
Usually there increased echogenicity in the region
where there is plon nephritis,
there can be decreased color doppler flow
and it's been shown that when there is thickening
of the wall of the renal collecting system that
that can be indicative of pyelonephritis as well.
So let's look at a few images.
This is a kidney that was swollen.
There's areas that look like they are hazy
increased echogenicity.
Looking at this one, we see more of a focal area
of increased echogenicity that correlated well
with A-D-M-S-A study.
This is the so-called focal lobar nephron.
It's important to follow this not only to look for scarring
with follow-up ultrasound about a month later,
but one cannot absolutely exclude a tumor.
A hematoma could have the same appearance
and obviously if it's pilo that will go away over time.
Hopefully not with scarring in the area.
If it's a hematoma
that will ultimately liquefy may also have some scarring,
but obviously if it's a tumor, it's not going
to diminish over time.
Here's an example of a patient
who has normal cortico medullary differentiation
in the upper portion of the kidney, the mid portion
and then in the lower pole there's a more focal area
of increased genicity color.
Doppler shows that there really is very little flow down
here confirming that there is a focal area
of pyelonephritis
and this is from the article by Robin showing
that there can be some thickening of the
collecting system in the presence of acute pilo
scarring duplex system in this particular child shows normal
parenchyma follow-up showed that there was scarring
around the lower pole.
Another example, the lower pole had nice rounding,
but in the upper pole there were areas of scarring.

CT and MR for Complicated Cases

Now, as I said before, CT and MR are usually not necessary
but are reserved for complicated urinary tract infection
where we can't show the abnormality with ultrasound.
The findings that we can see very easily
with these modalities are renal mely.
We may see focal areas of decreased contrast enhancement.
We may see perinephric stranding, renal abscesses,
perinephric abscess, easier to see with these modalities
and perinephric collections,
but those are usually pretty easy to see with ultrasound.
Here's an example
of a large perinephric election in this patient
with a urinary tract infection.
The abscess on CT we can see
after contrast enhancement is totally without
enhancement pilo.
If we look closely, we can see areas that look like there
are multiple areas of decreased enhancement.
This is very typical for pyelonephritis,
although you can't absolutely exclude masses such
as one may see with lymphoma.
Perinephric collections when they are
echoes can be very easy to see.
But if you look at this kidney, there is actually a rind of
moderately a coic material around the perinephric fat here.
And with ct it's a lot easier to see cystitis.

Cystitis

Most females who have urinary tract infection have cystitis
as their underlying abnormality.
They may present because they have urgency, frequency,
dysuria, hematuria.
They may complain of lower abdominal or pelvic pain.
They may have a onset
of urinary incontinence if they're already potty trained
and the parents may notice that the urine has a strong foul
odor With cystitis sono graphically,
we may not see any abnormality,
but there are children in whom we see thickening
of the bladder wall.
It may be diffuse, it may be focal,
and it seems to be more common in the presence
of a hemorrhagic cystitis due to viral etiologies.
And in fact, with viral cystitis,
the bladder wall may have characteristics
that are suggestive of rhabdo sarcoma.
But the history differentiates cystitis from tumor
with the ultrasound findings
and symptoms resolving within two weeks in the presence
of viral cystitis.
Here's an example of a patient who has loation
and thickening of most of the bladder wall laterally
and posteriorly, and there are many faces of cystitis.
This happens to be a patient who was treated with Cytoxan,
who had increased vascularity in the bladder wall in
addition to thickening and septation within the bladder.
In this patient there is
a polypoid protrusion not only from the anterior wall
but posteriorly.
And in this example we see bullous cystitis
where there are cystic changes in this area
of bladder wall thickening.
This patient had circumferential thickening
and irregularity of the bladder wall
and these all mimic rhabdomyosarcoma.
All of these examples have shown,
but in fact turned out to be viral cystitis.
This looks like a large mass in the bladder.
As the bladder distended, we see
that it's merely bladder wall thickening.
We don't expect a tumor to change its size of configuration.
Two weeks later, this was totally resolved.
Other conditions that can mimic cystitis include neurogenic
bladder, UCal, diverticular, bladder wall diverticular,
focal bladder wall thickening due to an indwelling catheter,
patients with prostatitis and of course tumor.
This is a patient with a neurogenic bladder.
Despite the fact that we asked her to try
to empty her bladder,
she never could achieve successful emptying.
Here are the little diverticula
around the bladder in this patient with spina bifida,
big diverticulum in this patient
that can certainly have static urine within it we see the
neck connecting to the bladder.

Recommendations for Workup

Now many babies present
with a prenatal sonographic report of hydro.
They don't have a urinary tract infection when they come in
and it's really important to delay the sonogram
whenever possible to the 10th day
of life when the babies are already well hydrated
and have good glomerular filtration.
If you think that the parents will have enough sense
to come back, it's always appropriate not
to do the study while the baby is still in the hospital in
the first couple of days
of life when they are relatively dehydrated.
Since there really isn't proof that there's any benefit
of prophylactic antibiotic therapy,
we can use serial sonography to determine if
and when VCUG is appropriate.
Always be respectful of the cancer risk
of radiation exposure in children
and instruct the parents regarding the importance
of urinalysis
and urine culture when their children have
unexplained fevers.
So the recommendations are really quite controversial
where I practice babies who are newborn to six months
who present with a first febrile urinary tract infection
will get an ultrasound
and A-V-C-U-G within the rest of the first year
of life over six months of age,
a first febrile urinary tract infection.
I would have to say that many
of these babies get an ultrasound and A-V-C-U-G,
but will definitely get A-V-C-U-G if the ultrasound
is abnormal.
With children who come in with cystitis,
generally we don't do A-V-C-U-G
unless the ultrasound is abnormal
and if they have recurrent urinary tract infection,
we don't do A-V-C-U-G if the ultrasound is normal.
Nuclear medicine studies are reserved
for children in whom we think there may be obstruction,
so they'll get a diuretic, renogram and CT
and MR when the sonography is inconclusive
or when it's necessary for surgical planning.
Remember, if you look for trouble, you're gonna find it
and there really is no proof of benefit of demonstrating low
to moderate grade.
Vesco ureteral reflux with A-V-C-U-G as there's no proof
of benefit from prophylactic therapy,
VCU G'S terrify parents and young children.
And unless it's absolutely indicated it shouldn't be done.
Now. It used to be we were getting VCU GS annually in the
children who had urinary tract infection
where reflux was demonstrated.
Now it's being done at less frequent intervals
and really when it's done is guided by
how the child is doing clinically as to when
to do the sonogram.
That is also dictated by the clinical
and laboratory findings.
And urine cultures are extremely important in monitoring
children who have vesco ureteral reflux
to determine if they've had a recurrent infection.

Conclusion

So thank you for the opportunity to share my experience
with you on urinary tract infection
in the pediatric age range.
Goodnight.