Paget’s Disease of Bone is our topic.
Prevalence of the bone disease - United Kingdom,
Australia, South Africa, US.
And with Paget’s disease of the bone, fundamentally
this picture pretty much tells you the story
of Paget’s disease.
The story… the story began with healthy
osteoclast and as the day wore on and as the
weeks wore on, years wore on, osteoclast…
Mr, Osteoclast kept… kept getting tired
and tired, tired until he pretty much died.
So, osteoclast, initially there might be too
much chaotic osteoclastic activity and functioning.
Therefore, initially, you would expect there
to be increased bone resorption, if you take
a look at the X-ray here.
And on your left, you’ll notice that the
bone appears quite lucent.
That’s because of increased bone resorption.
Keep that in mind.
So, therefore, the patient initially might
The story of osteoclastic activity continues
and he starts or she starts, whatever, the
cells start dying, starts burning out.
So, if osteoclastic activity starts dying
out, then please understand that there is
going to be increase in bone activity.
And with that increase bone activity, you
are then going to have thickening of the bone
as seen in the X-ray in the picture.
So, therefore, the picture on the right shows
you increased, thickened, white, opaque bone
Now, what I haven’t shown you here is that
there is a stage in between whereas I told
you there is declining functioning of the
So, initially, there was osteolytic lesion,
then there will be as the osteoclast burning
out a mosaic pattern, ultimately when we have
thickening of the bone, it’s called osteosclerosis
to the point where you might then cause compression
of certain cranial nerves, for example, the
And with such nerves being compressed, you
might have problems with hearing and maybe
even ringing in the ears.
Aetiology, to this day, really unclear, there
are a few theories out there and usually,
the patient that comes into you or when you
read about this patient, you’ll hear that
the patient is expressing that his or her
hat size might be increasing.
The pattern of bone involvement may involve
one or many bones asymmetrically.
Common sites include the pelvis, move a little
bit higher… lumbar , even higher… skull
and then in the pelvis region, you’re thinking
about the femur, one of the major common sites.
Most patients are asymptomatic with 90 percent,
others have bone pain, skeletal deformity.
This is what I was talking to you about earlier,
particularly the frontal and the occiput,
so the front and the back, either extremes
of the skull, especially during the osteosclerotic
phase, there might be enlargement of the skull,
but then that means to you that the patient
is expressing that his hat size is increasing.
There might be bowed lower extremity, increased
fracture risk… the more bone that you have
doesn’t necessarily mean that what?
It would be stronger.
Remember, you have to have remodelling, the
balance between osteoclasts and osteoblasts.
That balance in Paget’s disease has been
So, therefore, femur, tibia, radius, extremely
susceptible to pathologic fracture.
Impingement syndrome, what does that mean?
The last phase of Paget’s in which its osteosclerosis
may then cause, as I was explaining earlier,
compression of your cranial nerves.
So, therefore, the vestibulocochlear might
be affected in your ear, hearing loss and
perhaps even vertigo.
Late, uncommon manifestation… something
that you want to keep in mind.
So, let me give you some differentials or
better yet, why don’t you give me some differentials
in which the bone is becoming thicker.
What is it called when you hear about marble
bone disease that we talked about in ortho?
What if you had a patient that was older and
now, you find an adenoma in the anterior pituitary
and the patient is presenting as large hands,
large tongue, hat size is increasing.
You find that on laboratory studies that IGF1
Acromegaly, osteopetrosis, Paget’s disease…
you can then expect there to be increased
thickening of the bone, but each one will
be a little bit different.
How can you distinguish Paget’s disease
from let’s say osteopetrosis?
It’s easy with acromegaly, right?
In acromegaly, what did I give you for laboratory
Increased IGF1, hyperglycaemia, right, completely
Here, however, with Paget’s disease of the
bone, we have high output congestive… high
output heart failure from vascular shunts.
In other words, it’s an AV malformations
that you might find with Paget’s disease
of the bone.
Small percentage of your patients Paget’s
disease of the bone may result in and develop
osteosarcoma and immobilization results in
hypocalcaemia, especially in Paget’s disease
of the bone patients.
If you take a look at the right aspect of
this X-ray, then you’ll notice that it’s
actually quite normal.
The left aspect with all these arrows, these
arrowheads that you’re seeing, the left
side of this patient’s hip, you find there
to be increased thickening.
Thickened cortex, prominent trabeculae and
could have lytic features.
Remember, just because you have thickened
bone doesn’t mean that it’s stronger bone.
In fact, it’s increased prone or there’s
increased tendency of fracture to take place.
It may cause substantial pain, deformities
and disabilities, especially in the elderly.
It does not spread to other bones after those
that are affected, so do not think about adjacent
bones being affected, but the major bones
that are affected… pelvis, the femur, the
spine, the lumbar spine and maybe perhaps
the skull; in the skull, the frontal and the
Paget’s skull, enlargement of skull.
Well, it looks like one huge cotton wool appearance.
Hmm, the last time you’ve heard of cotton
wool was in your fundoscopic examination when
we talked about things like diabetes mellitus,
so you know what cotton wool is and what it
If it was looking like this, this is osteosclerosis,
you can expect the hat size to be increasing
and specifically in the occiput and the frontal
Remember also please, because of increased
thickness, there might be compression of the
cranial nerve such as the 8th cranial nerve
resulting with hearing loss and such and even
maybe perhaps vertigo.
Evaluation… lab studies isolated with now
the alk-phos here is going to be incredibly
That is the-one of the hallmark findings of
Paget’s disease of the bone.
You would never expect such an increase with
acromegaly and with the osteopetrosis, once
again, I’ve given you enough clues here
that without a doubt you know that your patient
has Paget’s disease of the bone such as
your AV malformation, such as the tendency
of developing osteosarcoma and the fact that
the alk-phos or alkaline phosphatase is elevated.
Look at this, greater than 500 units per litre.
The plain film can reveal the three phases
of the disease.
Early on, it looks like osteoporosis.
Keep that as a differential whenever you deal
with bone disease, especially with Paget’s
disease and osteoporosis.
Osteoporosis is completely different, different
presentation, maybe a female, post-menopausal.
Later on, you get mixing.
Who’s dying in the meantime?
In other words, which osteo cell is burning
Initially, there is too much activity.
Next, as it starts declining, there might
be a mix between osteoclast, osteoblast, you
call that a mosaic pattern and finally, third
phase would be your sclerosis with cortical
thickening, that I talked to you about earlier.
The bone scan, most sensitive test, can reveal
areas of increased uptake.
And migratory lesions should call a diagnosis
of Paget’s in to question.
Evaluate for alternative such as metastasis
to the bone.
Paget’s disease of bone.
Management, symptomatic patient evolve…
involving the axial skeleton, weight-bearing
bones; analgesics for the pain.
Remember, the Paget’s disease of bone can
be treated not cured, managed maybe perhaps
Bisphosphonate therapy, first line of the
Oral agents, these includes your risedronate
Remember that alendronate could also be used
The IV agents include pamidronate and zolendronate.
Oral agents such as alendronate is important
and we have IV agents such as pamidronate,
that is important.
Paget’s disease can monitor disease activity
with alk-phos in urine N-telopeptide.
Remember, once again, Paget’s disease of
the bone the major significant increase would
500 is the magic number.