In this lecture, we’re
going to discuss
deficiency or G6PD.
G6PD happens because of
a metabolic problem.
Here’s a glucose molecule.
Remember, glucose is now
broken down into pyruvate
and that goes into the
Krebs cycle to make ATP.
There’s also gluconeogenesis in the event
the liver wants to make more sugar.
Glucose has another enzyme
from the glucose-6-phosphate
molecule in that pathway,
which is glucose-6-phosphate dehydrogenase.
That feeds into the pentose phosphate shunt
whose job it is to make NADPH out of NADP.
NADPH is then used to make glutathione
and the glutathione is responsible
for maintaining our body’s
vigilant fight against
oxygen free radicals.
If we have a deficiency of
G6PD, we can make less NADPH
and that can result, in particular,
from our red cells from being
incapable of defending themselves
against oxidative stress.
So here’s an example of a
slide of a patient with G6PD.
What you can see is that the red blood
cells had become a little bit more fragile
and they’re being cleared by the spleen,
having this bitten out appearance
that you can see in that cell
right in the center of the slide.
Patients may also,
under special stain,
be found to have Howell-Jolly
bodies as in the slide here.
That’s also seen in some thalassemias.
So patients with G6PD
are generally males,
that’s because it’s
an X-linked disorder
and so it’s almost exclusively
in male patients.
This is a prevalent disease, is present
in about 1-2% of the U.S. population
and is more common in
in particular patients of African
or Middle Eastern descent.
So what happens to these patients?
Generally, this can result in a male
infant with a prolonged jaundice
or even frank kernicterus because
of that red cell breakdown
And because infants have a harder
time clearing that bilirubin,
they can develop a
is pretty much normal
and their CBC will look normal until the
patient has an event of oxidative stress.
This happens because of, for example,
an ingestion of a food product
that has much oxidative
stress within it.
And then these patients will
develop an acute hemolytic anemia.
In severe cases, the hemolysis is chronic
and there are no periods of relief,
but in most cases, this is an episodic
thing as a result of a stressful period.
So what are common sources of
oxidative stress in children?
These are things that
patients with this condition
must avoid for their
The classic one is
or any sulfa
Quinolones are also oxidative stresses
and so, children going to malaria prone
areas or being treated with malaria drugs
must avoid the quinolones.
Remember, if it ends in a -quin such
as chloroquine, that’s a quinolone.
Nitrofurantoin can provide
so we must avoid this drug
especially for treatment of urinary
tract infections and simple cystitis.
Aspirin may cause problems,
so we should avoid aspirin.
And although it’s not used very commonly,
methylene blue should be avoided as well.
More commonly though, foods are the thing
that get these patients in trouble
and we have to avoid certain
foods, specifically fava beans
or these broad-based beans are
source of oxidative stress.
Blue food coloring
can cause problems.
Tonic water, because it has quinine
in it, can also cause problems.
And interestingly, the gluten-free
diet can cause problems.
This is because in some
people insert fava beans or
some of those broad-based beans
as a way to supplement protein.
So, package reading has
to be carefully done.
There are randomly other
things that can cause it.
Any infection can cause
an oxidative stress,
in particular moth balls, if present,
can cause oxidative stress.
And diabetic ketoacidosis
can cause oxidative stress
in a patient who is unfortunate to
have both G6PD and type 1 diabetes.
So let’s look at how
these patients present.
Usually during in oxidative stress moment
when they have acute hemolytic anemia,
they will have a period of
acute irritability or fatigue.
These children will be tired
and they’ll be fussy.
And you’ll see signs of infection
if that’s their trigger,
but most importantly,
patients complain that they have
Coca-Cola or cola-colored urine.
That’s from the hemoglobinuria as
a result from the cell breakdown.
Patients on exam will be
found to have pallor.
They may have tachycardia and
they may have a flow murmur,
best heard at the upper sternal borders.
These patients may be
jaundiced because they
suddenly can’t clear
their cell breakdown.
They may have an acute
and in severe cases, they
may go into frank shock.
A CBC shows acute anemia
and evidence of hemolysis
and we may get some other labs as well.
An indirect bilirubin will be
elevated, as well as an LDH.
We can get a serum haptoglobin,
which will be abnormally low.
Haptoglobin binds to free hemoglobin,
that's why it is low in intravascular hemolysis.
Some important key things about G6PD,
first off, always remember
it’s all about avoidance.
We have to counsel them in terms
of things they need to avoid
they need to avoid.
If there is an acute hemolysis,
we may well need to transfuse.
And for rare cases, especially those
cases where there is no period
during which they are
not getting a break,
we may pursue splenectomy as a way to
mitigate some of that cell breakdown.
So that’s a brief summary of G6PD.
Thanks for your time.