Fluid in too many spaces and places: Hydrops - HD

Introduction

Hi, my name is Debbie Levine.

I'm from Beth Israel Deaconess Medical Center in Boston
and Harvard Medical School.

Today I'll be speaking about fluid in too many spaces
and places fetal hydros.

Today we'll be talking about fetal hydrops
and my objectives are to illustrate the appearance
of fluid in the different fetal body cavities.

Discuss the differential diagnosis of the etiology
of hydro drops and discuss the use
of middle cerebral artery doppler in the assessment
of fetal anemia, which is a frequent cause of hydrops.

What is Hydrops?

What is hydrops?

It's an abnormal interstitial accumulation
of fluid in body cavities.

Those body cavities are the pleural cavity,
the pericardial cavity, and the peritoneal cavity.

You need two of these for a diagnosis of hydrops,
or you could have fluid in one body cavity along
with soft tissue edema involving the entire fetus.

Distinguishing from Lymphangiectasia

Anasarca, a lot of people get confused by the term
lymphangiectasia and they'll frequently call a fetus
early in pregnancy having hydro drops when in fact
it's lymphangiectasia.

Lymphangiectasia is
what you're seeing in this slide when you've got a lot
of edema in the subcutaneous tissues,
but you don't necessarily have fluid in the
different body cavities.

This is not hydro drops, this is still a very,
very poor prognostic feature.

In fact, it would be almost unheard of for a fetus
that looks like this with such severe lymphangiectasia
to survive.

Associated Findings

Another finding that's commonly seen in hydrops
but not needed for the diagnosis
of hydrops is placental magaly.

In this slide we've got a fetus
who clearly has fluid in the abdominal cavity
and who also has anasarca.

You can see all of the edema in the soft tissues here.

Here we're looking at the placenta
and these are our centimeter markers.

I'll tell you that this fetus was only about 20 weeks,
and you can see that this placenta is
about three centimeters.

In general, the placenta can be as thick
as a millimeter a week.

This would be much too thick.

Polyhydramnios is another very common finding in hydros,
but it's not needed for the diagnosis of hydro drops.

Different people use different numbers for the diagnosis
of polyhydramnios, an amniotic fluid index, for example,
of greater than 20 or 22,
or a single pocket of greater than eight.

Causes of Hydrops

Let's talk now to what are the causes of hydro drops
and many, many different etiologies
can lead to hydro drops.

It's a late stage of many different processes that lead
to redistribution of body fluids
and these body fluids redistribute among the intravascular
and interstitial compartments.

Here we can see a fetus with hydro drops
and there's actually fluid in the neck,
in the soft tissues of the neck.

There's the anasarca, the soft tissue edema.

There's ascites here as well.

You can see the very small appearance of the lungs.

Here we can see placental magaly.

Again, you don't need that for hydro drops,
but you can see the skin thickening
and the fluid in the pleural cavity outlining the lungs

here on a sagittal view, we've got fluid in the neck,
we've got a little bit of fluid around the lungs.

This is the diaphragm right here.

Then we've got fluid in the fetal abdomen.

The etiology is an imbalance of interstitial fluid
and this can happen for many different reasons.

Heart failure, high cardiac output failure,
decreased colloid oncotic plasma pressure such as
what we see in anemia, increased capillary permeability
and obstruction of venous or lymphatic flow.

Identifying Fluid in Body Cavities

Let's go back a little bit
and talk about how we actually figure out what fluid spaces
the fluid is in, what body cavities the fluid is in,
and how we know which body cavity these are.

Ascites

One of the earliest signs
of hydrops will be fluid in the peritoneal cavity
or ascites.

Here you're gonna see fluid around loops of bowel.

Here we've got a view of the abdomen
and we've got bowel loops here
and we've got fluid around them

here we're a little higher in a different fetus
and we've got the liver and we can see
fluid around the liver.

You also might see fluid outlining umbilical vessels.

Here we're right just
above the umbilical cord insertion site into the abdomen,
and you can actually see the umbilical vein right
here surrounded by fluid.

This can be very confusing if you've never seen the
umbilical vessels outlined by fluid before.

You need to be able to recognize
that umbilical vein in the abdomen.

The umbilical arteries are next
to the bladder, the fetal bladder.

What we can see in this image are the two umbilical
arteries stretching back to go around
the fetal bladder in this fetus with ascites.

If it's a male fetus,
the fluid in the scrotum will actually communicate
with the fluid in the peritoneal cavity
and you'll frequently end up with bilateral hydroceles.

I wanna emphasize that hydroceles are very,
very commonly seen in male fetuses
and they are not a sign of hydrops as an isolated finding.

Pseudoascites

Pseudo ascites is a term that you might have heard of
every now and then you'll see a hypoechoic area just
below the skin and you might think is that fluid?

You need to remember
that sometimes the abdominal wall muscles
or the abdominal wall fat can look hypoechoic.

They can look dark and they can look like fluid.

The way you'll figure that out is by looking up and down
and seeing if there's fluid anywhere else,
and recognizing the normal position of
that hypoechoic band along the anterior
and lateral fetal abdomen wall.

Here's another example of a normal fetus,
and we're looking at this hypoechoic band right here.

As we get further down in the abdomen,
this hypoechoic band isn't extending into the interstices
and along and around the abdominal loops of bowel.

That's how we know that this is a normal finding.

I wouldn't mention pseudo ascites in a report
because that might get
the clinicians worried when indeed this is a normal finding.

In fact, if you look up above the spine here,
you can also see that this musculature is looking very
hypoechoic.

Another example of pseudo ascites right
below the chest wall, abdominal wall here.

Seeing this hypoechoic band note
that this doesn't surround the liver
and it stops at the insertion of the ribs.

Isolated Ascites

Sometimes we'll see ascites fluid in the peritoneal
cavity, and that's the only finding that we'll see.

If you remember what I said at the beginning
of this lecture, you need fluid in two body cavities
to be called hydrops.

If it's just in the peritoneal cavity, that's ascites.

This can be an early sign of hydrops,
but if it's truly isolated, you're going to think
what could cause that fluid.

It could be a urinary etiology, for example,
if there's an obstructive uropathy
and then the bladder, one of the kidneys ruptures.

It could be due to a GI obstruction, again
with a perforation of a bowel loop and meconium peritonitis.

If there's only ascites,
this has a much more favorable prognosis than
full-blown hydrops.

You do need to follow up these fetuses to ensure
that hydrops does not ensue.

Here's an example of isolated ascites,
and you can see that this is a large amount
of fluid in the abdomen.

It's surrounding the bowel loops.

When we look up in the chest here,
we don't see any pleural
effusion in this case.

The abdominal fluid was so much
and we weren't sure what the etiology was
that we actually did a fetal drainage procedure.

This is something very, very rare to do
for isolated ascites,
but we wanted to give the lungs a chance to grow
and actually wanted to decompress the fluid cavity.

You can see this is basically an amniocentesis needle
going into the fetal abdomen.

Pleural and Pericardial Effusions

Let's move on now to the chest and pleural
and pericardial effusions.

These tend to occur later in hydrops,
and if they're isolated findings, they could be
of a more benign etiology than hydrops,
but you need to be able to tell the difference
between a pleural fluid and pericardial effusion
because these have different etiologies
and potentially different treatment.

Small Pleural Effusion

A small pleural effusion might be seen
and might not cause any problem
for the fetus at all if it's unilateral.

In this case, we just have a little sliver of fluid
around the lung, and doesn't shift the mediastinum.

The problem is that these small effusions can get larger
and if they get larger, they can actually cause mass effect.

Once they cause mass effect, they're going
to cause mediastinal shift.

In these cases, you wanna look for a hernia
or another chest mass as the cause of the fluid.

Here we are looking at the small
pleural fluid in this fetus
with an isolated pleural effusion.

Medium and Bilateral Pleural Effusions

This is an example of a medium-sized pleural effusion.

What you can see here, this is the fluid right here,
and here's the lung and here's the heart.

The heart is actually not shifted
very much in the chest.

It's still in a relatively normal location,
but this is obviously a fetus
that you'd wanna watch very carefully.

Here's a fetus with a bilateral pleural effusion,
and what you can see here is the so-called bat wing
appearance where you've got fluid around both lungs,
and you can see the heart anteriorly in the chest.

If the fluid is very, very large,
if there's a large amount of pleural effusion,
it can actually cause compression of the lungs
and when the lungs are compressed, they can't grow
and develop normally.

This can be a cause of pulmonary hypoplasia.

If pleural effusions occur early
and if they're long standing, and if they're large
and cause mediastinal shift, those are the ones
that we might want to treat by doing a thoracoamniotic
drainage procedure.

You'll notice in this fetus,
that there's also a small amount of ascites,
so this would count as hydrops.

Here we've got large bilateral pleural effusions
and a fetus with a large amount of soft tissue edema.

Those two findings together would be enough for us
to say this is a hydrotic fetus,
and you can see how compressed those lungs are in the
central part of the chest,
and you can imagine how that might lead
to pulmonary hypoplasia.

Chylothorax

Sometimes the only thing
that we'll see is a unilateral large pleural effusion,
and in that case the most likely diagnosis is a
primary chylothorax.

This is the most frequent cause
of an isolated pleural effusion.

This can lead
to respiratory distress in the newborn.

What you can see in this fetus is
that the heart is shifted over in the chest,
that the lungs are compressed
and that there's a large effusion.

Sometimes we'll actually drain these during pregnancy,
to help with development of the lungs,
and sometimes we'll drain them right
before delivery, to help alleviate
any immediate neonatal respiratory distress.

There's the heart shifted over, these are unilateral,
they shift the mediastinum and they flatten the diaphragm.

When you drain one of these large effusions,
what you'll find is a large number
of lymphocytes in clear yellow fluid.

You might think, how do you know then
what the etiology is?

When we think about a chylothorax
and neonates, usually that has a milky appearance,
but the chyle doesn't actually become milky until
after the infant feeds.

That's why in utero this will be clear yellow fluid.

We drain this fluid
to help prevent pulmonary hypoplasia
and to assist in peripartum care.

Pericardial Effusion

Let's now move to pericardial fluid.

This will be fluid around the heart.

One of the important things to know is that we
frequently see a small sliver of fluid
around the heart in normal fetuses.

Unless this becomes large
or looks like it's causing compression it's not
something to worry about.

Here again, we see a normal appearing heart
with just a sliver of pericardial fluid, not something
that I would worry about.

In this case, there's a lot of fluid around the heart.

How do I know that this isn't a pleural effusion?

How do I know it's a pericardial effusion?

What we can see is that the lungs are posterior here,
they're being pushed posteriorly
and the fluid isn't going around the lungs,
it's pushing the lungs posterior,
and the fluid is around the heart.

You're not getting a bat wing appearance,
you're getting the appearance of a heart floating in fluid.

Pericardial fluid, the lungs are pushed backwards,
pleural fluid, the lungs look like
they're floating in the fluid.

The other thing that you can do is flip the fetus over,
flip the mom, look at it from a different angle,
and again, you'll see that the lungs are always pushed
to the posterior aspect of the fetus
and the heart is floating in the fluid.

Skin Edema (Anasarca)

Let's now turn to skin.

This is a fetus with obvious very abnormal heart.

You can see a large heart here.

This is the etiology of the hydrops,
but what we're looking at here is how thick
and abnormal the subcutaneous tissue looks.

It looks very, very edematous here.

We're looking around the head
and we're measuring the head appropriately
because the head measurements are around the bone, not
around the skin.

You can see
how edematous the skin is here looking here anteriorly,

I do a lot of fetal MRI
and I just thought this was a very nice example of
what anasarca looks like.

This is that same fetus that I just showed you.

Obviously there's fluid in the abdomen
and you can see the umbilical vein here,
which I talked about earlier.

Umbilical vein right here,
umbilical arteries going down low,
bowel loops surrounded by fluid, fluid in the chest.

This is all the soft tissue edema.

You can see how much this looks like the amniotic fluid
and you can see how it totally surrounds the fetus.

Biometric Assessment in Hydrops

How does hydrops affect our biometric
assessment of the fetus?

I mentioned earlier that
around the head we're going to look around the bone.

What does it do elsewhere?

You wanna be sure that you don't get faked out
and that you really pay attention to
how biometry should be performed so
that you can accurately assess the gestational age.

Different computers,
different ultrasound equipment will calculate the
gestational age differently,
but as a rule of thumb,
we usually take the four measurements by parietal diameter,
head circumference, abdominal circumference,
and femur length, and pretty much average them out
to come up with a fetal gestational age.

You can imagine if there's a lot of anasarca
that you're going to get larger measurements if you go
around the outside of the skin.

It turns out that for the abdominal circumference,
we do wanna go around the outside of the skin
because we use the abdominal circumference
to estimate fetal weight,
but the definition of the head circumference
and BPD as I said before is around the bone.

If you're estimating gestational age, then you need
to go into your machine
and take out that abdominal circumference so
that you're not overestimating the age of the fetus.

Here we've got a fetus with hydrops
and we're appropriately measuring around the bone,
around the skull and not around the skin.

Here we have a fetus, again with anasarca
and for the abdomen, we're measuring
around the skin, not around the bone.

When you look at that dating parameters, you can see,
that the head
and the femur are about 19 weeks, five days,
but the abdomen about 28 weeks.

You use the abdomen for an estimate
of fetal weight, which makes sense
because the anasarca is contributing to the fetal weight,
but not for the gestational age.

Here we've got this date sheet of a different fetus,
who also had hydrops and had anasarca.

What you can see is
that the abdomen measuring 34 weeks is much further along,
than the average gestational age.

When you put that in,
you're driving up the other numbers.

When you get an estimated fetal weight of 96%, it's
because of that abdomen circumference.

For the ultrasound age, we want
to take out the abdomen circumference.

Instead of using the abdomen
and the calculation of the gestational age, we're only going
to use the head measurements and the femur.

Causes of Hydrops: Immune Hydrops

Let's go back now and talk about causes of hydrops.

Again, there can be immune hydrops
or non-immune hydrops.

Prior to the use
of RhoGAM immune hydrops was very, very common.

In fact, it accounted for about 80% of all cases of hydrops.

But now at least in the United States,
non-immune hydrops is much more common
because we give so much RhoGAM.

That gets rid of the immune hydrops cases
and it leaves the non-immune hydrops
as being the common cause of hydrops 90% of the time.

We can't forget about immune hydrops
because some individuals come in not knowing
that they have an issue with Rh
or with one of the other factors.

Immune hydrops has also in the past been called
erythroblastosis fetalis,
and it's when you have antibodies in the maternal
circulation that destroy the fetal red blood cells,
this will lead to fetal anemia.

The liver and the spleen become large.

You'll have increased erythropoiesis, hypoproteinemia,
and ultimately congestive heart failure.

Rh Sensitization

Maternal Rh sensitization occurs
during fetal maternal hemorrhage.

This can occur at delivery,
so it won't affect a first baby,
it will affect a subsequent baby, but it can also occur
after a miscarriage.

Spontaneous abortion or therapeutic abortion.

You can have mixture of the fetal and maternal blood
and sometimes women won't have known
that they had a spontaneous abortion earlier on in life.

They'll just think they had a delayed or a heavy period.

That's how somebody during a so-called first pregnancy,
can have Rh sensitization.

You might do an amniocentesis early in pregnancy
and cause some fetal maternal hemorrhage, abruption
or incompatible blood transfusions can also be a cause.

Transplacental hemorrhage can also occur.

In fact, it's very common in many pregnancies.

It's usually just a very, very small amount.

This is another reason why somebody
with a first pregnancy might come in
with Rh sensitization if they had
a transplacental hemorrhage.

It turns out that if you have a D negative woman
that if she's had bleeding like this, there's a 3% risk
of sensitization.

We give RhoGAM when we think the patients need it.

The dose is given there 300 micrograms at about 28
weeks, and that protects against 30
milliliters of fetal blood.

If there's been a greater degree
of fetal maternal hemorrhage, you can do a very,
very old fashioned test that's still
around a Kleihauer-Betke test that's utilized
to quantify the amount
of fetal blood in the maternal circulation
and you can actually calculate the dose needed.

Atypical Antibodies

Let's now turn
to talking about the atypical antibodies.

Rh is the one we all hear about,
but there are many, many other antibodies
that can cause immune hydrops
and these develop in one to 2% of individuals
after blood transfusion
and they account for about 2%
of hemolytic disease of the fetus.

That number changes as the use
of RhoGAM increases.

The common antibodies that we think about are the Kell,
the RhC, and the E.

We also need to remember if you have somebody
who you know is Rh negative,
and if you're doing some kind of invasive procedure
to the fetus, that you need to give RhoGAM,
you don't need to give it that minute,
but you need to give it within 48 hours.

In some cases, if the mom is known to be Rh negative
and the father of the baby is Rh negative, you don't need
to give RhoGAM.

Other people feel more comfortable not being sure
who the father of the baby actually is giving RhoGAM
to everyone who is Rh negative.

Screening and Diagnosis for Immune Hydrops

In the past when we were screening for Rh sensitization,
we would determine the Rh status of the parents.

We would monitor antibody titers
and look for antibody titers of one to eight or greater.

We would determine the Rh status of the fetus.

That would have to be an invasive test, do an amniocentesis
for the optical density, which was increased in hemolysis.

Then if there was a suspicion of anemia,
we would do the PUBS procedure.

Percutaneous umbilical blood cord sampling.

A lot of this is very, very invasive.

Nowadays though we look at the MCA doppler
and I'll be talking about that in a little bit.

Causes of Hydrops: Non-Immune Hydrops

Let's now turn to non-immune hydrops.

In Southeast Asia, this is commonly caused
by being homozygous alpha thalassemia patients.

The carrier status is very, very common
for alpha thalassemia in Southeast Asia,
it occurs in about five to 15% of the population
and it accounts for 60 to 90%
of non-immune hydrops in this region
and a quarter of perinatal deaths

in the Caucasian population who I usually deal with.

We see this in about one in 3000 live births,
non-immune hydrops
and alpha thalassemia is not the common cause.

Where you are in the world is gonna determine
how you think about hydrops in the Caucasian population.

Cardiac abnormalities, infection
and karyotype abnormalities in particular Turner syndrome.

Trisomy 13, 18, 21
and triploidy are the common causes of non-immune hydrops.

Why will this occur?

Usually because of increased hydrostatic pressure,
primary myocardial failure, arrhythmias, anemia,
twin twin transfusion syndrome, myocarditis,
heart malformations,
and high output cardiac failure, such
as can occur when there's an arteriovenous shunt.

You can also have hydrops
because of decreased plasma oncotic pressure.

For example, in a fetus who's very sick with hepatitis
cirrhosis, which is pretty uncommon,
in the fetus would cause decreased albumin formation.

This very rare fetal nephrosis
where you'll actually have increased albumin excretion.

You can have increased capillary permeability such as
with anoxia or infection
or obstruction to lymphatic flow, such
as can occur in Turner syndrome or,
and commonly you might have some combination of the above.

Cardiovascular Abnormalities

Let's talk about cardiovascular abnormalities.

Again, in the Caucasian population, these would account
for about 20 to 40% of non-immune hydrops.

It's rare for an isolated cardiac abnormality
to cause hydrops
because in the fetus there's
that parallel blood flow circulation.

But in structurally abnormal fetuses,
there are other factors with
or without cardiac abnormality that can lead to hydrops.

When we talk about fetal arrhythmias,
we're not talking about the isolated atrial beat
that comes early,
but it would usually be one of the tachyarrhythmias so
that the heart is beating very fast
for prolonged periods of time.

Here's that fetus I showed you earlier with a very,
very abnormal appearing heart.

Obviously congenital heart disease
is causing part of this problem.

You can see the severe skin edema
and the pleural effusion here in the abdomen,
the large amount of ascites.

Here around the head the soft tissue edema.

Here's this fetus, fetal MRI again showing
the ascites, the pleural fluid and the skin thickening.

Cardiac Tumors

Cardiac tumors can also cause hydrops.

Cardiac rhabdomyomas are one
of the more common cardiac tumors
that we'll see usually in association with tuberous sclerosis.

It's not the tumor itself that causes the problem.

It's usually going to be the location of the tumor
and if it causes obstruction.

That can be diastolic filling impairment alteration
of the function of the AV valves or outflow obstruction.

It's the location, the size,
and the number of the lesions that are gonna correspond
to the risk of hydrops.

A very rare pericardial
or cardiac tumor would be the mediastinal teratoma.

Because of the size of these lesions,
because they compress the heart,
sometimes if they have an AV shunt,
they can cause hydrops.

This is that fetus with a large pericardial teratoma
and it's really hard to even tell
what's going on in this case.

I'll point out the tumor to you
and you can see it right here.

Again, right here you can see the ascites in the
abdomen, the ascites in the abdomen,
and this large pericardial tumor.

Tachyarrhythmias

Tachyarrhythmias.

We define when the rate is sustained
above 200 beats per minute in the fetus.

These are usually going to be a
supraventricular tachycardia.

The diagnosis is important since the treatment can actually
reverse the cause of hydrops
and it's very, very rare for us to have a curable cause
of hydrops that we can take care of.

If a tachyarrhythmia is the cause of hydrops,
it's important to figure that out.

Some people would think,
why don't we just deliver the baby and treat it outside?

But it turns out that if you have a premature fetus
with a tachyarrhythmia, it can be very, very hard
to take care of that infant.

They'll often try
and treat the mom to treat the fetus,
and avoid delivery of a hydropic preterm fetus.

In this case, with the tachyarrhythmia
of 240 beats per minute, they treated the mom with digoxin
and then amiodarone
and the supraventricular tachyarrhythmia resolved.

GI Disorders

GI disorders can also cause hydrops.

They can cause this by being a local obstruction
to lymphatic and or venous flow.

You might see that in a GI obstruction
of omphalocele or gastroschisis.

Frequently you'll see meconium peritonitis.

As I mentioned earlier when I was talking about fluid
just in the peritoneal cavity,
these GI disorders usually cause
isolated ascites and not hydrops.

Here we're looking at a fetus with an omphalocele,
and I'll get my arrow here.

I've got the cursors around the omphalocele
and you can see a little bit of ascites in that sac
of the bowel and liver that's been extruded.

Renal Anomalies

Renal anomalies are rare cause of hydrops,
but again, as I mentioned
before, can cause fluid in the retroperitoneum
or peritoneal regions.

Bladder rupture can occur and cause urinary ascites,
but very, very rarely hydrops.

Here we've got a nice picture of a keyhole deformity
in a fetus with urinary outflow obstruction
that later on led to ascites
with urinary bladder rupture.

Aneuploidy

I mentioned before that aneuploidy can be
a cause of hydrops.

If you see a fetus with a large cystic hygroma,
you're going to think about an aneuploid
etiology for the hydrops.

Here we can see the skin thickening.

Here we can see a very short femur.

Here we can see fluid in the thoracic cavity
and anterior abdominal wall defect.

You're gonna definitely think about one of the trisomies
or Turner syndrome in this case.

Let's spend a minute looking at the biometry.

You can see that
by her dates she's 15 and a half weeks.

The head size, again, we're measuring around the bone,
is gonna be about 15 and a half weeks.

The abdomen we're measuring around the skin,
so it's 19 weeks and the femur length here is short.

14 weeks. It's still a straight bone.

It's morphologically normal, but it's short.

That's another finding that we might see in aneuploidy
as a cause of hydrops.

Twins

Twins can cause hydrops for many,
many different reasons.

First off, twins have a higher incidence
of congenital abnormalities than do singleton fetuses.

The reason why someone's having twins, an older age woman,
for example,
or assisted reproduction technology
can also lead to increased twins
and increased congenital abnormalities.

If you have twins who share a placenta,
they're also at increased risk
for twin-twin transfusion syndrome
and the recipient twin can end up getting hypervolemia,
polyuria, polyhydramnios and ultimately hydrops.

Here we can see a case of twins.

You can see the membrane between the two sacs
and you can see that sac
of B is very large compared to the sac of A.

Of course you'd have to look all around to make sure
that that was a constant finding.

You can also have the so-called acardiac twin,
where the pump twin is doing all the pumping for its co-
twin who doesn't have a normal heart
that pump twin can go into high output cardiac failure,
the acardiac twin will end up with anasarca,
not true hydrops,
but anasarca with all of the skin thickening.

Here we've got the look of the acardiac twin
and you can see how thick all of this skin is with
that anasarca, you don't have the normal development
of the brain since most of the blood flow is going to the
lower extremities
and abdomen of this
acardiac twin without a functioning heart.

Other Causes

Other causes of hydrops
and there's not enough time
to go into these in detail are skeletal dysplasias,
metabolic disorders and syndromes.

Tumors

Let's talk a few minutes about tumors.

The tumor itself is not causing hydrops,
but the increased blood flow associated with the tumor can.

If you have a tumor that's very, very vascular
and has arteriovenous malformations, this can lead
to high output cardiac failure
and it can also lead to a consumptive coagulopathy,
also called the Kasabach-Merritt sequence.

You can also have teratomas
that just plain have increased flow and
because of the increased flow, they can lead
to the AV shunting and this Kasabach-Merritt sequence.

Mirror Syndrome

People also talk about mirror syndrome
and what is mirror syndrome?

It's when the mother gets sick
mirroring what's happening in the fetus.

You get maternal anasarca in a pregnancy complicated
by fetal hydrops
and this can actually be life-threatening
for the pregnant woman.

What you will see is massive edema.

Oliguria and hemodilution,
we definitely don't wanna miss this.

Fetal Anemia Causes

What are the causes of fetal anemia?

The first one would be that there's excessive loss
of blood cells, such as what you'll see
in alpha thalassemia.

If you're gonna think about
that in people from Southeast Asia,
you can have intrinsic hemolysis, for example,
as I mentioned before, in AVMs
and tumors, you might have a reason
that the fetus bled a lot trauma, for example,
or you might have infection.

The infections that we think about are parvovirus, CMV,
syphilis and toxoplasmosis.

Hydrops in these cases can be reversible without any
treatment, but they can also cause other
associated abnormalities.

For example, with the TORCH infections,
we can see calcifications in the pericardium.

The brain or ventriculomegaly

infection will lead to high output failure for one reason,
by anemia, but it can cause other problems.

That can also lead to the hydrops, for example.

It can cause a liver inflammation, hepatitis, inflammation
of the heart myocarditis and full-blown sepsis.

Parvovirus

Parvovirus is going
to be the most common infection that we'll see.

We can test this looking for IgM in the maternal blood
or high or increasing IgG
or nowadays we will tend to use the PCR identification
of the parvovirus genome in the amniotic fluid.

If you do a tap of the fetal cord, a cordocentesis,
you'll see aplastic anemia, anemia with few reticulocytes.

What we do when we see parvovirus, when we know
that the mother's been infected is
that we'll end up doing very, very frequent scans
of the fetus in order to check for signs of hydrops.

Here we can see a fetus that's been exposed
to parvovirus and we can see a little bit
of fluid in the abdominal cavity.

Just a very, very tiny sliver of a pericardial effusion.

This is the kind of fetus you would watch
and not necessarily intervene on
further on in gestation.

You can see pericardial effusion here.

You can see that the heart is not beating very well.

I have images here labeled diastole and systole.

You don't see a lot of contraction during systole
because there's a myocarditis going on.

Weekly serial ultrasounds for eight
to 12 weeks after the maternal infection.

Assess for signs of hydrops, perform doppler for anemia.

Middle Cerebral Artery Doppler for Anemia

What is this doppler that we're doing?

It's the middle cerebral artery doppler
and we're looking at the cerebral circulation.

This is normally a high impedance circulation
and it has continuous forward flow.

The fetus wants to protect the brain.

It wants blood flow going to the brain at all times.

Why do we do the MCA?

Because it's a very accessible cerebral vessel.

It's very reproducible
and it carries the vast majority of the cerebral blood flow.

When a fetus becomes hypoxemic,
you get central redistribution of the blood flow,
you get increased blood flow to the brain
and the peak systolic velocity goes up.

Here we're looking at the circle of Willis in the brain.

Let me get my arrow to come here. Here's the arrow.

This is the MCA right here,
and we're putting our doppler gate on the MCA
and we're measuring the peak systolic velocity.

There are charts to look up
what the peak systolic velocity is
with respect to gestational age.

Gestational age is very important, so you wanna make sure
that you're assessing the gestational age appropriately.

Usually you're going to use the head measurements if there's
a problem with the abdomen or the femur.

It turns out, if you look at this,
MoMs are multiples of the median.

That as you go up
and get above two multiples of the median,
you almost certainly are dealing with anemia.

You look at the circle of Willis,
you get a transverse plane
of the fetal head at the base of the skull.

You put your doppler gate in the longitudinal view almost
parallel to the ultrasound beam.

Prognosis and Treatment

The prognosis in hydrops is grim.

Once a fetus is in full-blown hydrops,
70% will end up dying. 100%
if there's a structural abnormality identified.

If a fetus is anemic, then it's actually possible
to reverse the hydrops
by doing a transfusion, but not always.

What's interesting is
that sometimes even if there's anemia,
if you don't transfuse the fetus,
the hydrops may still resolve spontaneously
and you can think about that maybe the fetus was ill
and had some kind of viral infection, was able to fight
that off and got better.

If you don't do a transfusion
and anemia is the cause of the hydrops,
about a third will resolve spontaneously
and about a third will die in utero.

If you do a transfusion, you can improve the odds
and have about 53% resolve and 17
or 18% die in utero.

It's not a cure all transfusion
is not going to cure the problem.

The fetus will still be sick.

What's interesting is that if you do a transfusion,
that's not necessarily all the reason why the fetus got
better, because a lot
of them will resolve spontaneously.

Transfusions and PUBS Procedure

How do we do this procedure?

How do we find out if the fetus is anemic?

Once we've done that MCA doppler, we actually need
to get into the umbilical cord
to check the actual hematocrit.

We're going to look at the placenta
and look at the cord insertion site into the placenta.

If you go for a free floating loop of cord,
it can be very hard because the cord moves around.

Where we like to go is right near the placental
cord insertion site.

We wanna go right into a vein there.

You wanna use packed red blood cells, meaning
that the blood cells that you're transfusing have a
hematocrit greater than 90%, and that's
because you don't wanna give too much volume to the fetus.

This will be O negative irradiated blood.

Your goal is to reach a fetal hematocrit of 40.

Here we are doing an MCA Doppler
and we've got our systolic right here.

That's at 53 centimeters per second.

This is a fetus at 26 weeks with an elevated MCA Doppler.

This is a fetus
who might benefit from a PUBS procedure.

Here we are looking at the cord insertion site into the
placenta and picking an appropriate location
to put our needle.

Here we are going into that particular
location here.

We've got a fetus I showed you
before with hydrops, skin thickening, pleural effusion,
omphalocele, definitely abnormal.

Doing a PUBS for this fetus is not going to be helpful.

You need to figure out who is going
to benefit from an invasive procedure
and only do it when you have a high suspicion of
curable cause of hydrops.

Like I said when I discussed this fetus
before, there was a short femur,
which is gonna make you think of a karyotype abnormality
and a cystic hygroma,
which is gonna make you think even more of Turner syndrome.

Definitely think about chromosome abnormalities
and these kinds of fetuses. Lymphangiectasia I mentioned
before because it's almost universally fatal.

You wanna make sure that you can recognize it
and use that term appropriately.

It turns out that these early fetuses
with lymphangiectasia have chromosome abnormalities
in two thirds of the cases.

Summary and Diagnostic Approach

Let's summarize for hydrops, the diagnostic approach,
you need a maternal history, depends where the mom is from.

Ethnicity is important.

Maternal blood type is important to think about.

Isoimmunization diseases
that you think about are anemia and infection.

Consanguinity can lead to anomalies.

Find a history of both the
pregnant woman and her partner.

Family history is important as is medication use.

Obstetric history would include looking
for affected siblings in any history
of prior abortion or stillbirth.

The maternal studies that might be considered being done
as blood group typing
and indirect Coombs test, a CBC, the Kleihauer-Betke test
and testing for infection, syphilis, parvovirus,
CMV, toxo and others.

That might be
thought about due to the patient's history.

The diagnostic approach is to start with ultrasound.

Ultrasound is a wonderful tool,
but in many cases we can't find
the cause of the hydrops.

That turns out to be about 15 to 30% of the cases.

Echocardiography is important
because the heart can either be the primary etiology
or can be secondarily involved in hydrops.

Amniocentesis is important for the karyotype abnormality.

You don't want to do a transfusion in cases
of lethal karyotype abnormalities.

You might want to check the alpha-fetoprotein, antigen tests
by PCR culture for syphilis testing, for CMV and Toxo
or others as suggested by history,
you wanna do an MCA Doppler
and if that's elevated,
consider doing the percutaneous
umbilical blood cord sampling.

The follow up, the getting the best diagnosis is gonna be
important, not just for the current pregnancy,
but also to be helpful in counseling
regarding recurrence risks in future pregnancies.

Conclusion

Thank you very much for your attention.