Paget's Disease
Paget's Disease is a condition where the remodelling of bones is
abnormal, resulting in deformity, pain and fragile bones. Normal
bone is a living tissue which is constantly altered throughout
life - the bone is broken down by one type of cell (osteoclasts)
and then built up again by another (osteoblasts). In Paget's
Disease this remodelling process
is accelerated and newly formed bone has less time to become
structurally organized, and is therefore
weaker.
Paget's Disease is a condition which usually affects people over
the age of 50, and is slightly more common in men than in women.
It is particularly common in the UK and Australia but the incidence
world
wide is not
known.
The cause is still uncertain but includes having a genetic predisposition.
Another event, perhaps later in life, may then start off the disease.
What are the symptoms?
Paget's Disease can affect any bone but it is most common in the
skull, pelvis and leg bones. The bones may become deformed, for
example the long bones may become bowed or the skull may become
larger. Because
the bone structure is abnormal the bones may be painful and are
more likely to fracture.
How can Paget's Disease be diagnosed?
Instead of new bone being laid down in neat parallel rows, in
Paget’s
disease it has a disorganized structure and this can easily be seen
on X-Rays of the affected bones.
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Xray of bone showing Paget's Disease |
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Xray of normal bone |
How is it treated?
The management of this condition has been revolutionized
by the introduction of bisphosphonates. These drugs inhibit the activity
the
osteoclasts. Currently in
the UK the two bisphosphonates in clinical use are oral risedronate
and intravenous
pamidronate
or zoledronate. Risedronate is given over a two month period
and needs to be taken fasting because bisphosphonates are badly
absorbed
from the gut.
For those patients in whom there is a problem with oral treatment
(the bisphosphonates as a group may cause heartburn or indigestion)
the drugs can be given as an intravenous infusion. While oral
treatment can be given by your General Practitioner, the intravenous
infusion needs a hospital out-patient visit.
Treatment usually controls both the symptoms and the abnormal bone
remodelling and may last for several months before another course
is needed. There is uncertainty whether the best approach is to
give enough bisphosphonate to control symptoms alone or whether
it is best to reduce bone remodelling to within the normal range
and this issue is currently being studied in the PRISM trial run
by the University of Aberdeen.
Questions patients ask
Why is my affected bone painful?
Because
the increase in size of the affected bone stretches nerve fibres
over the surface and this causes pain. Paget’s
disease also increases the wear and tear of major joints that
occurs in all of us as we age and this may also cause pain.
Will my Paget’s disease spread from one bone to another?
No. The disease will spread within an affected bone
but this can be prevented by treatment. Pagets disease never moves
from
an affected to a non-affected bone.
More information
National Association for the Relief of Paget's Disease
The Paget Foundation
The Arthritis Society
Arthritis Research Campaign
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