Paget's disease disrupts the normal cycle of bone renewal and repair, causing bones to become weakened and deformed.
Bone pain is the most common symptom of Paget's disease, often affecting the pelvis or spine. The pain is usually worse when lying down.
You should visit your GP if you experience bone pain or notice any bone deformities.
However, in many cases of Paget's disease, there are no noticeable symptoms and it's only diagnosed during tests for an unrelated medical condition, or when a bone is fractured.
Why does Paget's disease happen?
Paget's disease is caused by a problem with the process of bone regeneration, which results in bone being replaced at a faster rate than usual. This leads to enlarged bones that are weak and brittle.
It's not clear why this happens, but both genetic and environmental factors are believed to be important. There is a family history of the condition in around 10-15% of cases.
Treating Paget's disease
The condition is not usually treated immediately if you're not experiencing symptoms, although your health will be regularly monitored.
Treatment can help relieve symptoms and prevent the condition getting worse, but there's no cure for Paget's disease.
Medication can help control bone regeneration, with a type of medicine called bisphosphonates being the first choice. These are taken as a tablet or given as an injection.
Over-the-counter painkillers such as paracetamol and ibuprofen can help relieve bone pain.
Surgery is only used if Paget's disease causes further problems, such as osteoarthritis or a bone fracture.
Complications of Paget's disease are uncommon, but can be serious. They include bone deformities, hearing loss and osteoarthritis.
In very rare cases, Paget's disease can cause heart failure or bone cancer.
Who is affected?
After osteoporosis, Paget's disease is the second most common type of bone disease in the UK, although the number of cases is declining.
It most often occurs in people of white British descent and is very rare among other ethnic groups.
The UK has the highest rates of Paget's disease in the world. It's also relatively common in countries with high levels of migration from Britain, such as Australia, New Zealand and South Africa.
Paget's disease is an age-related condition and rarely affects young people. It's estimated about 2-3% of white adults aged over 50 have the condition in the UK.
Other types of Paget's disease
Paget's disease is named after James Paget, an English surgeon, who first described the condition's symptoms in 1877. A number of other conditions were also named after James Paget, including:
Paget's disease of the nipple – a rare type of breast cancer
Paget's disease of the penis – another rare type of cancer
To avoid confusion, healthcare professionals often use the term "Paget's disease of the bone" to distinguish this condition from the ones above. However, for ease of reading, this topic uses the term "Paget's disease" to refer to "Paget's disease of the bone"
Symptoms of Paget's disease
Paget's disease often has no symptoms and many people don't know they have the condition.
The most common symptom is bone pain, but may include joint pain and signs of a nerve being compressed or damaged.
Paget's disease usually affects the bones of the pelvis or spine. Other affected bones may include:
bones in the arms and legs, particularly the thigh and shin bones
More than one bone is affected in two out of every three cases of Paget's disease.
When to seek medical advice
See your GP if you:
have persistent bone pain or notice deformities in any of your bones
have persistent joint pain
experience any neurological symptoms, such as numbness, tingling or loss of movement
These symptoms are discussed in more detail below.
Bone pain caused by Paget's disease has been described as a constant, dull pain deep within the affected part of the body. The pain is usually worse at night when you are lying down. The affected area may also feel warm.
As Paget's disease progresses, you may experience deformities in the affected bones, such as twisted or misshapen limbs, or scoliosis(curvature of the spine). Affected bones can sometimes break (fracture), particularly the longer bones in your arms and legs.
If Paget's disease develops inside the bones of your skull, it can cause the following symptoms:
hearing loss – which can be total or partial
vertigo – feeling very dizzy or the sensation you are moving when standing still
tinnitus – a constant buzzing or ringing noise in your ears
Abnormal bone growth can cause damage to nearby cartilage, which is the thick, spongy tissue that cushions your joints. Cartilage damage can lead to progressive joint damage, known as osteoarthritis.
Symptoms of osteoarthritis include:
joint tenderness or stiffness – usually worse when you wake up, but improves once you start to move
joints appearing larger than normal
difficulty moving your affected joints
Compressed or damaged nerves
Many of the major nerves in your body run through, or alongside, your bones. Abnormal bone growth can result in a bone compressing (squeezing) or damaging a nerve.
Depending on which nerve is affected, this can lead to a wide range of symptoms. Possible symptoms affecting the nerves (neurological symptoms) include:
pain travelling from the base of your spine down into your legs(sciatica)
pain travelling from your neck into your arms and chest (cervical radiculopathy)
numbness or tingling in the affected limbs (peripheral neuropathy)
partial loss of movement in your limbs
loss of balance
bowel incontinence or urinary incontinence (loss of bowel or bladder control)
Causes of Paget's disease
Paget's disease is caused by abnormal bone regeneration, although it's not clear exactly why this happens.
Bone cells regenerate in a similar way to skin, so old bone is removed and replaced by new bone. This cycle is known as bone remodelling.
Two specialised cells are responsible for bone renewal and repair. These are known as:
osteoclasts – cells that absorb old bones
osteoblasts – cells that make new bone
In Paget's disease, something goes wrong with the osteoclast cells and they begin to absorb old bones at a much faster rate than normal.
The osteoblasts then attempt to produce new bone at a faster rate than normal. However, this means the new bone becomes weak, unstable and larger than normal over time.
Possible causes of Paget's disease
The exact cause of Paget's disease is unknown, but it's likely to be caused by a combination of genetic and environmental factors.
These are described below.
People who inherit certain mutated genes from their parents have an increased chance of developing Paget's disease.
The most important of these is a gene called SQSTM1. People with a mutation in this gene have a greatly increased risk of developing Paget's disease in later life. Seven other genes have now been identified that also increase the risk of Paget's disease substantially.
In about 10-15% of cases, Paget's disease runs in families. If you have a close relative with Paget's disease, such as a parent, brother or sister, you are seven to eight times more likely to develop the condition.
The number of people affected by the disease has fallen sharply over the last 50 years in the UK. In contrast, the number of people affected in other countries has remained static, which indicates that environmental factors may play a role.
The severity of symptoms also seems to be decreasing. Up to 60 years ago it was not uncommon for people to experience severe symptoms in multiple bones, but this is no longer the case.
The reasons for these differences are unclear.
One theory is that Paget's disease might be caused by a slow-acting viral infection. Possible triggers include:
canine distemper virus – responsible for a type of viral infection that affects animals, mainly dogs (distemper)
respiratory syncytial virus (RSV) – which causes respiratory infections during childhood
As a result of vaccination programmes, both measles and distemper are now uncommon infections. This could account for the decrease in cases of Paget's disease.
Another theory suggests people with rural lifestyles may be at increased risk of developing Paget's disease. As the number of people living this type of lifestyle is now much less common, it could offer an alternative explanation for the fall in cases of Paget's disease.
Improvements in nutrition and a reduction in cases of rickets over the past 50 to 100 years have also been suggested as possibilities for the decreasing severity of Paget's disease.
Diagnosing Paget's disease
As Paget's disease doesn't always cause symptoms, many cases are diagnosed during tests for another condition.
In some cases it may be possible to diagnose Paget's disease based on a physical examination. However, blood tests and scans will usually be needed to confirm the diagnosis.
It's not yet known whether an early diagnosis is effective in preventing the most serious complications of Paget's disease, such as hearing loss and bone deformity.
Alkaline phosphatase (ALP)
People with Paget's disease often have raised levels of an enzyme called alkaline phosphatase (ALP) in their blood. A blood test can be used to detect this, but many other conditions can also cause a raised level of ALP.
ALP is sometimes called serum alkaline phosphatase (SAP) or bone-specific alkaline phosphatase (BSAP).
X-rays and bone scans
An X-ray can determine whether the bones have become enlarged. In some cases, the condition is diagnosed after an X-ray for another problem, such as a bone fracture.
A bone scan may also be recommended. A small amount of a harmless radioactive substance is injected into your blood, which collects in the areas of bone where the most regeneration is taking place.
A special camera known as a gamma camera is used to highlight where the radiation has collected.
Further testing is usually only required if:
you develop abnormalities affecting one or more joints
you are experiencing neurological symptoms – symptoms affecting your nerves, such as pain, numbness or tingling
a diagnosis of bone cancer is suspected (although this is very rare)
In these circumstances, tests may include:
a bone biopsy – where a sample of bone is removed under local or general anaesthetic so it can be studied in detail
a computer tomography (CT) scan – where a series of X-rays of the affected bone are taken to show a detailed three-dimensional image
a magnetic resonance imaging (MRI) scan – another type of scan where a strong magnetic field and radio waves can build up an image of the inside of the affected bone
Treating Paget's disease
Paget's disease doesn't always require treatment. If treatment is needed, there are several options to help relieve symptoms.
If a blood test reveals you have Paget's disease but you're not experiencing any symptoms, you probably won't receive treatment immediately.
Instead, your progress can be carefully monitored with regular blood tests, known as "watchful waiting".
Treatment is usually recommended if you have symptoms such as bone pain, or pain, numbness and tingling.
Treatment can't cure Paget's disease, but it can relieve symptoms and prevent the condition getting worse. Treatment also reduces your chances of developing any complications of Paget's disease.
Treatments for Paget's disease include:
medication to help regulate bone growth
medication to relieve pain
Regulating bone growth
There are a number of different medications used to help regulate bone growth in cases of Paget's disease.
If you're being treated with one of these medicines, you may have regular blood tests or X-rays to check they are working.
Bisphosphonates are the first-choice treatment to regulate bone growth. They work by controlling the cells that absorb old bone (osteoclast cells), which means the bone regeneration process should return to normal.
A type of bisphosphonate called risedronate is usually recommended. Risedronate is available in tablet form. Most people are advised to take one tablet a day over the course of a two-month period.
Take your risedronate tablet while you're standing or sitting up, and avoid lying down for at least 30 minutes after taking it. This will help prevent heartburn (burning chest pain and discomfort).
Side effects of risedronate include:
If you're unable to take risedronate because you're unable to stay upright for 30 minutes, there are alternative bisphosphonates, such as pamidronate. Pamidronate is given by injection, usually once a week over the course of six weeks.
The most common side effects of pamidronate include:
mild flu-like symptoms, such as a high temperature
However, these side effects usually pass within 48 hours of receiving an injection.
Zoledronic acid, also called zoledronate, is a newer type of bisphosphonate increasingly being used as an alternative to risedronate or pamidronate.
It is given as an injection and its effects can last a long time. You may only need an injection once every two years.
Flu-like symptoms, such as chills, fever and joint pain, are common after receiving your first injection, although these side effects should pass within three to four days.
Calcitonin used to be a common treatment for Paget's disease, but is only used in certain circumstances now.
If you have low levels of calcium in your blood (hypocalcaemia), it's unsafe to take bisphosphonates because they can lower your calcium levels further.
In these circumstances, an alternative medication called calcitonin may be recommended. Calcitonin is a man-made version of a hormone known to prevent bone loss. It's given by injection once a day.
The recommended course will depend on how well you respond to treatment, although it usually lasts between 6 and 18 months.
Common side effects of calcitonin include:
changes in how things taste
In most cases, painkillers available over the counter, such asparacetamol or ibuprofen, should relieve the symptoms of bone pain. If your symptoms continue, your GP can prescribe more powerful painkillers.
If you have Paget's disease, your GP may recommend taking regularcalcium supplements. Both of these help strengthen your bones.
Some medications for Paget's disease can also reduce the levels of calcium in your body, so you may need to "top up" your levels by taking supplements.
Some people with Paget's disease find they benefit from physiotherapy or occupational therapy, particularly people with fractures or other types of damage in the bones of their legs or spine.
There are devices available that are designed to reduce the weight placed on the affected bones, which should help reduce pain and make everyday physical activities easier. Examples include:
walking devices – such as a cane or walking frame
orthotics – insoles made of plastic that fit inside your shoe to help support your feet
spine braces – designed to support the spine in the correct position
Some therapists also use different types of energy, such as electric currents or impulses, to stimulate the nervous system (energy-based therapy). The electric impulses are thought to ease pain and promote healing in some people.
The therapist will also be able to teach you a number of exercises to:
improve your muscle strength
maintain the range of movement and flexibility in your joints
increase your physical stamina
Surgery is usually only used if Paget's disease causes further problems, such as bone fractures.
If you develop a fracture, surgery may be required to realign the bones so the affected bone is able to heal properly.
If you experience severe osteoarthritis, surgery may be required to repair or replace a damaged joint. Surgical options for osteoarthritis include:
arthroplasty – where the damaged joint is removed and replaced with an artificial joint; the most commonly performed arthroplasties are hip replacements and knee replacements
arthrodesis – where the joint is fused into a permanent position
Surgery may also be used if you develop bone deformities. A procedure called an osteotomy involves carefully cutting the affected bone so it can be straightened. This operation is usually carried out under general anaesthetic, so you will not experience any pain.
Complications of Paget's disease
Paget's disease can cause several further problems to develop, although these are usually rare.
The abnormally rapid process of bone regeneration associated with Paget's disease can sometimes lead to a build-up of calcium in the blood. The medical term for this is hypercalcaemia.
Hypercalcaemia only occurs in people with Paget's disease who have been confined to bed after having an operation or a fracture. However, even in these circumstances hypercalcaemia is quite rare.
Symptoms of hypercalcaemia include:
bone pain (or worsening bone pain if already present)
It's also relatively common for people with hypercalcaemia to developkidney stones.
Hypercalcaemia can be treated using a combination of medications to lower blood calcium levels and slow down bone regeneration.
In severe cases of Paget's disease, the blood vessels inside the bones can become damaged. This means the heart has to work harder to pump blood around the body.
Sometimes the heart may no longer be able to pump enough blood around the body to meet demand. This is known as heart failure and is a very rare complication of Paget's disease.
Symptoms of heart failure include:
breathlessness (dyspnoea) when you are more active than normal, or sometimes when you are resting
extreme tiredness and weakness
oedema – swelling in the legs, ankles and feet
Heart failure can be treated using a combination of medications designed to reduce strain on the heart while also helping it work more efficiently. In some cases, surgery may be recommended to repair or replace a damaged heart valve.
Bone cancer can, in very rare cases, occur as a complication of Paget's disease. It's estimated fewer than 1 in 1,000 people with Paget's disease will go on to develop bone cancer later in life, usually many years after Paget's disease was first diagnosed.
Symptoms of bone cancer include:
bone pain very similar to the pain associated with Paget's disease itself – a dull ache, usually worse at night
swelling around the affected bone
a noticeable lump in the affected bone
Sarcoma is usually an aggressive type of cancer, and it's often necessary to remove the affected bone to prevent the cancer spreading to other parts of the body.
The changes to your bones caused by Paget's disease can also cause other problems, depending on which bones are affected.
These problems may include: