00:00
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
osteoclasts and as the day wore on and as the weeks wore on, years wore on, osteoclasts,
mister osteoclasts kept getting tired and tired, tired until he'd pretty much die. Huh, so
osteoclasts initially there might be too much chaotic osteoclastic activity and functioning,
therefore initially you'd 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 have hypercalcemia. The story of osteoclastic activity continues and he starts or she
starts, whatever, the cells start dying. It starts burning out. So, if osteoclastic activity
starts dying out, then please understand that there's going to be increased bone activity
and with that increased 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 representing osteosclerosis. Now what I haven't shown you
here is that there is a stage in between whereas I've told you there was declining functioning
of the osteoclasts. So initially there was osteolytic lesion, then there'd be as the osteoclasts
are burning out a mosaic pattern. Ultimately, when you 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 vestibulocochlear and with such nerves being compressed you might have
problems with hearing and maybe even ringing in the ears. Etiology to this day really unclear.
02:24
There're a few theories out there and usually the patient that comes in to 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 because you're thinking about the femur; the major common sites.
02:59
Most patients are asymptomatic where the 90%. Others have bone pain, skeletal deformity.
03:06
This was 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 remodeling, the balance between osteoclasts and
osteoblasts. That balance in Paget's disease has been forever lost, 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. The 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's it
called when you hear about marble bone disease that we talk about in ortho? That's
osteopetrosis. What if you had a patient that was older and you find an adenoma in the
anterior pituitary and the patient is presenting as large hands, large tongue, hat size is
increasing? You find on laboratory studies that IGF1 is elevated. That's acromegaly.
04:53
Acromegaly, osteopetrosis, Paget's disease, you can then expect there to be increased
thickening of the bone, but each one would be a little bit different. How can you distinguish
Paget's disease from, let's say, osteopetrosis? It's easy with the acromegaly, right? An
acromegaly whether that I give you for laboratory tests, increased IGF1, hyperglycemia,
right, completely different presentation. Here however, with Paget's disease of the bone, we
have high output, congestive high output heart failure from vascular shunts, in other words
this is AV malformations that you might find with Paget's disease of the bone. Small percentage
of your patient's Paget's disease of bone may result in and develop osteosarcoma and
immobilization results in hypercalcemia especially in Paget's disease of the bone patients.
05:48
Paget's hip, if you take a look at the right side of this patient, 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've
thickened bone doesn't mean that's stronger bone. In fact, it's increased prone or there is
increased tendency of fracture to take place. It may cause substantial pain, deformity 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, the pelvis, the femur, the spine, lumbar spine, and maybe perhaps the skull; in the
skull, the frontal and the occiput. Let's take a look at the clinical presentation of Paget's
disease of the bone, in other words von Recklinghausen disease of the bone. Take a look at
that skull lit up and opaque. So would you call that an osteolytic type of appearance? Would
you call that a mosaic or do you think it would be more of an osteoblastic type of
appearance? Osteoblastic, correct? Because the osteoclasts have died and at this point
you're in the state of sclerosis, hence extreme, extreme opacity. So in the Paget's skull,
oftentimes the patient is going to present with "doc, my hat size is increasing because my
head is getting bigger not due to ego but due to Paget's disease of the bone," enlargement of
the skull associated with cotton wool appearance, and the osteoporosis circumscripta refers
to the fact that, well, you could have regions of the bone that may be a little bit osteolytic.
07:56
If you take a look at the frontal region of the skull here, you'll notice that it is a little
lucent. So what osteoporosis circumscripta refers to is the osteolytic changes you expect in
the bone early on in Paget's disease. Evaluation, lab studies, isolated ____. The alk
phos here is going to be incredibly elevated. That is one of the hallmark findings of Paget's
disease of the bone. You'll never expect such an increase with acromegaly and with
osteopetrosis once again I've given you enough clues here that without a doubt you know
that your patient has Paget's disease of bone such as your AV malformation that suggest 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 liter. The plain film can reveal the 3
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
completely different, different presentation, may be a female postmenopausal. Later on you
get mixing. Who's dying in the meantime? In other words which osteo cell is burning out?
The osteoclasts. Initially there was too much activity. Next as it starts declining, there might
be a mix between osteoclasts, osteoblasts and you call that a mosaic pattern and finally
3rd phase will be your sclerosis with cortical thickening that I've talked about earlier. The bone
scan most sensitive test can reveal areas of increased uptake and migratory lesions should
call diagnosis of Paget's in to question, evaluate for alternative such as metastasis to the
bone. Paget's disease of the bone management, symptomatic patient involving the axial
skeleton weightbearing bones analgesics for the pain. Remember the Paget's disease of bone
can be treated, not cured, managed may be perhaps with bisphosphonates. Bisphosphonate
therapy, 1st line of severe disease. Oral agent, these include your risedronate and
alendronate. Remember that alendronate could also be used for osteoporosis. The IV agents
include pamidronate and zoledronate. Oral agents such as alendronate are important and we
have IV agents such as pamidronate that is important.
10:35
Remember once again that with Paget's
disease of the bone the major significant increase would be alk phos, 500 is the magic number.