Paget's disease is a chronic condition that causes increased breakdown and regrowth of bone. It most commonly affects the pelvis, legs, skull, and spine. People with Paget's disease may experience bone pain, deformities, and fractures as the abnormal bone growth weakens the bones. While the cause is unknown, genetic and environmental factors likely play a role. Treatment focuses on regulating bone growth with bisphosphonate medications or surgery for complications like fractures.

1. Paget's DISEASE
Paget's (PAJ-its) disease of bone interferes with your body's normal recycling process, in
which new bone tissue gradually replaces old bone tissue. Over time, bones can become
fragile and misshapen. The pelvis, skull, spine and legs are most commonly affected.
Definition:
A chronic condition in which both the breakdown and regrowth of bone are increased.
Paget disease of bone occurs most frequently in the pelvicand leg bones, skull, and lower
spine. It is most common in older individuals, and may lead to bone pain, deformities, and
fractures. Also called osteitis deformans.
Types:
There are two types of Paget's disease of bone.
 Monostotic type: When a single site of bone is affected by Paget's disease,
it is referred to as the monostotic type.
 Polyostotic type: When multiple sites of bone are affected by Paget's
disease, it is referred to as the polyostotic type.
Pathophysiology:
Any bone can be involved in Paget disease.
The bones most commonly affected are the pelvis, femur, and skull. Other less
commonly involved bones are the tibia, vertebrae, clavicle, and humerus.
Bone turnover is accelerated at involved sites.
Pagetic lesions are metabolically active and highly vascular.
Excessively active osteoclasts are often large and contain many nuclei.
Osteoblastic repair is also hyperactive,
causing coarsely woven, thickened lamellae and trabeculae.
This abnormal structure weakens the bone, despite bone enlargement and areas of
bone sclerosis.

2. Etiology & Risk factors:
The cause of Paget's disease of bone is unknown.
Scientists suspect a combination of environmental and geneticfactors contribute to the
disease. Several genes appear to be linked to getting the disease.
Some scientists believe Paget's disease of bone is related to a viral infection in yourbone
cells, but this theory is controversial.
Risk factors:
Factors that can increase your risk of Paget's disease of bone include:
 Age. People older than 50 are most likely to develop the disease.
 Sex. Men are more commonly affected than are women.
 National origin. Paget's disease of bone is more common in England,
Scotland, central Europe and Greece — as well as countries settled by
European immigrants. It's uncommon in Scandinavia and Asia.
 Family history. If you have a relative who has Paget's disease of bone, you're
more likely to develop the condition.
Symptoms:
Most people who have Paget's disease of bone have no symptoms. When symptoms
occur, the most common complaint is bone pain.
Because this disease causes your body to generate new bone faster than normal, the rapid
remodeling produces bone that's less organized and weaker than normal bone, which can
lead to bone pain, deformities and fractures.
The disease might affect only one or two areas of your body ormight be widespread. Your
signs and symptoms, if any, will depend on the affected part of yourbody.
 Pelvis. Paget's disease of bone in the pelvis can cause hip pain.
 Skull. An overgrowth of bone in the skull can cause hearing loss or headaches.

3.  Spine. If your spine is affected, nerve roots can become compressed. This can
cause pain, tingling and numbness in an arm or leg.
 Leg. As the bones weaken, they may bend — causing you to become
bowlegged. Enlarged and misshapen bones in your legs can put extra stress
on nearby joints, which may cause osteoarthritis in your knee or hip.
Complications
In most cases, Paget's disease of bone progresses slowly. The disease can be managed
effectively in nearly all people. Possible complications include:
 Fractures and deformities. Affected bones break more easily, and extra blood
vessels in these deformed bones cause them to bleed more during repair
surgeries. Leg bones can bow, which can affect your ability to walk.
 Osteoarthritis. Misshapen bones can increase the amount of stress on nearby
joints, which can cause osteoarthritis.
 Neurological problems. When Paget's disease of bone occurs in an area
where nerves pass through the bone, such as the spine and skull, the
overgrowth of bone can compress and damage the nerve, causing pain,
weakness or tingling in an arm or leg or hearing loss.
 Heart failure. In severe cases, your heart may have to work harderto pump
blood to the affected areas of your body. Sometimes, this increased workload
can lead to heart failure.
 Bone cancer. Bone cancer occurs in up to 1% of people with Paget's disease of
bone.
Diagnosticevaluation:
> History collection
> Physical examination
Blood test
A simple blood test can be carried out to check the level of a substance called alkaline
phosphatase (ALP) in your blood.

4. People with Paget's disease of bone often have raised levels of ALP, although some people
with the condition have a normal ALP level and a high level can also be caused by some
other conditions.
An X-ray or scan is therefore also needed to confirm the diagnosis.
X-ray and bone scan
An X-ray can show whether your bones have become enlarged as a result of Paget's
disease of bone.
Sometimes a bone scan called scintigraphy may also be carried out to checkhow much of
your body is affected by the condition.
For this scan, a small amount of a radioactive substance is injected into your blood. This
collects in areas where there's a lot of bone renewal taking place.
A gamma camera is then used to detect the radiation and highlight affected parts of the
body.
Further tests
Further tests are usually only needed if you have signs of more severe Paget's disease of
bone or your doctorthinks there's a chance you could have bone cancer (although this is
very rare).
In these cases, you may be advised to have a:
 bone biopsy – a sample of bone is removed under anaesthetic so it can be looked
at in detail
 CT scan – a series of X-rays of the affected bone are taken to create a detailed 3-
dimensional image
 MRI scan – a strong magnetic field and radio waves are used to create an image of
the affected bone

5. Treatment:
Bisphosphonates
Bisphosphonates are medicines that help regulate bone growth. They workby affecting
the cells that absorb old bone (osteoclasts).
There are several bisphosphonates available, including:
 risedronate – a tablet taken once a day for 2 months
 zoledronate – a one-off injection
 pamidronate – either 6 weekly injections or 3 injections every 2 weeks
 These can help regulate bone growth and reduce pain for several years at a time.
 Treatment can be repeated when the effect starts to wear off.
 The most common side effect of risedronate is an upset stomach. The main side
effects of zoledronate and pamidronate are flu-like symptoms that last a day or 2.
Painkillers
Over-the-counter painkillers such as paracetamoland ibuprofen can help relieve pain
caused by Paget's disease of bone.
Surgery
Surgery is usually only needed if further problems develop, such as fractures, deformities
or severe osteoarthritis.
Operations that may be done include procedures to:
 realign the bones after a fracture so that they heal correctly
 remove and replace a damaged joint with an artificial one, such as a hip
replacement or knee replacement
 cut and straighten deformed bones
 move bone away from a squashed (compressed) nerve
These operations are usually done under general anaesthetic, so you'll be asleep and will
no t experience any pain while they're carried out.

6. Diet and nutrition
Calcium and vitamin D help keep your bones healthy. If you have Paget's disease of bone,
it's important to ensure you get enough of these.
You get calcium from your diet. It's found in foods such as:
 dairy foods – such as milk and cheese
 green leafy vegetables – such as broccoli and cabbage
 soya beans, soya drinks with added calcium and tofu
You get most of your vitamin D from sunlight, although it's also found in some foods such
as oily fish.