Okay, so now we're going
to talk a little bit more
about the immune
The the specific ones.
So, Polyarteritis Nodosa.
The epidemiology is that
there's a peak incidence,
kind of in the middle
years of 45-65.
It's much more common
in men than in women.
Again, the etiology is unknown,
but it's due to immune
Typically, where you get
deposition the immune complexes
is that branch
points of the vessel.
So that's where we have
kind of turbulent flow
so that kind of
makes some sense.
And the inflammatory process weakens
the arterial wall leading to thrombosis.
That then leads to ulcerations, infarcts,
ischemic atrophy, and hemorrhage.
Signs and symptoms of
include involvement of the renal artery
in which case you will get hypertension
because we are reducing flow through the
renal artery or the renal arterioles.
The glomerulus senses that
there's diminished flow,
that diminished flow leads
to elaboration of renin,
which will then cleave angiotensinogen to
angiotensin as we've learned previously,
and we're often running in
terms of driving hypertension.
Renal artery involvement in
polyarteritis nodosa is very common.
So hypertension, acute onset
hypertension is very common as well.
Coronary involvement occurs
in about a third of cases.
And clearly the same mechanisms
that are involving the renal artery
and the injury and thrombosis can lead to
an increased risk of myocardial infarction.
Occurs in just a little under half of patients
ulcerations and nodules,
and then you can have a number
of gastrointestinal lesions.
Basically, wherever the immune
complexes are depositing,
that's where you're going
to get symptomatology.
And because nerves are
vascularized structures as well,
you can have neuritis,
you can have inflammation of the nerves,
and you can have particularly
of the motor nerves.
so that's polyarteritis nodosa,
that's kind of a small and medium sized
arteries of immune complex deposition.
Let's look at smaller
So we're going to look at
the microscopic polyangiitis,
and Churg-Strauss Syndrome.
These are going to be due to
antineutrophil cytoplasmic antibodies.
Oh, remember those.
Okay, so if you think vasculitis
overall is relatively rare,
this is really really rare.
Still, it's a very interesting
mechanism of disease.
And if we don't find clear
cut immune complex deposition,
we typically invoke antineutrophil
This is also called
Pauci-immune complex vasculitis,
meaning that there really
aren't immune complexes.
Okay so, the antibodies are directed
against neutrophil primary granules
that include the proteins
proteinase 3 and myeloperoxidase.
It turns out similar structures
are present on monocyte lysosomes.
So they can also be
And those granule contents,
once they're extruded by neutrophils
can settle onto
You can have antibodies that are
directed against endothelial cells
that had been coated with
proteinase 3 or myeloperoxidase.
We won't necessarily see antibodies present
in the vascular lesions in the vasculitis.
But if we see elevated levels of
antineutrophil cytoplasmic antibodies,
those are considered very
useful diagnostic markers.
So, depending on whether the antibodies
are primarily against proteinase 3
or primarily against
we have different
So if you have antibodies
against proteinase 3
that disease entity is
On the other hand, if you have
that's usually associated
with Churg-Strauss Syndrome
but can also be with Microscopic
Polyangiitis and Granulomatosis.
Let's look at some of the
epidemiology of this disease.
we don't know what drives this.
We don't understand why
people develop antibodies
but they do.
It's often present in older age
groups, 6th and 7th decade.
It will affect men
and women equally.
It's much more common in the white
for reasons that
are not yet known.
And unlike polyarteritis nodosa,
Polyangiitis due to ANCAs,
the lesions tend to all be of the
same age in any given patient.
much more broadly.
In polyarteritis nodosa, you can have
lesions of various different ages,
and they tend to crop
up in one location
and then in another location
in another location.
So Microscopic Polyangiitis associated
with antibodies to myeloperoxidase
can be elicited
not in all cases,
but can be elicited by
administration of certain drugs
such as penicillin can also
happen following infection.
It can also happen with the presentation
of a variety of protein therapies.
When we see it in the kidney,
and this is showing you a glomerulus from
a patient with Microscopic Polyangiitis.
We can see what is a
So the glomerulus,
what's left of it is that little
shrunken hyper pink tuft in the middle
and surrounding it is an
epithelial cell proliferation.
So this is a very aggressive,
Signs and symptoms very
fatigue, weight loss.
Patients because of the involvement
of the pulmonary vascular bed
can have hemoptysis not a
common feature but can occur
because of the involvement of the
renal vascular bed can have hematuria.
There can also because of the
glomerular damage be proteinuria.