Symptoms of Paget's disease of bone include bone pain, joint pain and problems caused by a nerve being squashed or damaged.

But in many cases, there are no obvious symptoms and the condition is only found during tests carried out for another reason.

1 bone or several bones may be affected. Commonly affected areas include the:

• pelvis
• spine
• skull
• shoulders
• legs

Bone pain

Bone pain caused by Paget's disease is usually:

• dull or aching
• deep within the affected part of the body
• constant
• worse at night

The affected area may also feel warm.

Joint pain

Abnormal bone growth can damage nearby cartilage, the spongy tissue that cushions your joints.

This can lead to "wear and tear" of the affect joints (also known as osteoarthritis), which can cause:

• joint pain
• joint stiffness
• swollen joints

The symptoms are usually worse when you wake up and improve a bit as you start to move.

Nerve problems

Abnormal bone growth can result in bone squashing (compressing) or damaging a nearby nerve.

Possible signs of this can include:

• pain travelling from the spine down into your legs (sciatica)
• pain travelling from your neck into your arms and chest
• numbness or tingling in the affected limbs (peripheral neuropathy) 
• partial loss of movement in your limbs
• balance problems
• loss of bowel control or loss of bladder control

Other problems

Paget's disease of bone can also cause a range of other problems, including:

• fragile bones that are more likely to break
• deformities in affected bones, such as curved legs (bow legs) or a curved spine (scoliosis)
• hearing loss, headaches, vertigo (a spinning sensation) and tinnitus (a noise in your ears) – these may occur if the skull is affected
• too much calcium in the blood
• heart problems

Read more about the complications of Paget's disease of bone.

When to see a GP

See a GP if you have:

• persistent bone or joint pain
• deformities in any of your bones
• symptoms of a nerve problem, such as numbness, tingling or loss of movement

A GP can organise tests to check your bones and look for problems such as Paget's disease of bone.

Read more about how Paget's disease of bone is diagnosed.

Paget's disease of bone can be diagnosed with a blood test and an X-ray or scan.

Blood test

A simple blood test can be carried out to check the level of a substance called alkaline phosphatase (ALP) in your blood.

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 check how 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 doctor thinks 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

There's currently no cure for Paget's disease of bone, but treatment can help relieve the symptoms.

If you do not have any symptoms, your doctor may suggest keeping an eye on your condition and delaying treatment until any problems occur.

Bisphosphonates

Bisphosphonates are medicines that help regulate bone growth. They work by 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.

If you're unable to have bisphosphonates, you may need daily injections of another medicine that prevents bone loss called calcitonin.

Painkillers

Over-the-counter painkillers such as paracetamol and ibuprofen can help relieve pain caused by Paget's disease of bone.

Make sure you read the packet or leaflet before taking painkillers, to check whether they're suitable for you and to find out how much to take.

If these do not help reduce your pain, your GP can prescribe more powerful painkillers.

Supportive therapies

Some people with Paget's disease benefit from supportive therapies such as physiotherapy or occupational therapy.

These therapies involve exercises and techniques that can help reduce pain, improve movement and make everyday tasks easier.

Devices that reduce the weight placed on the affected bones may also help, such as:

• a walking stick or frame
• orthotics – insoles made of plastic that fit inside your shoe to help support your feet
• braces that support the spine in the correct position

Some therapists also use treatments such as transcutaneous electrical nerve stimulation (TENS) – a method of pain relief involving the use of a mild electrical current. The scientific evidence for TENS is not strong, but some people find it helpful.

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.

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.

Sometimes your GP may suggest taking extra calcium and/or vitamin D supplements to ensure you're getting enough.

Paget's disease of bone can sometimes lead to further problems.

Broken bones

Bones affected by Paget's disease of bone tend to be more fragile than normal bone and are more likely to break (fracture) – even after a relatively minor injury.

Signs of a fracture include:

• sudden, severe pain
• swelling or tenderness around the injured area
• bleeding, if the bone has damaged the tissue and skin 

It's not clear whether bisphosphonate medication helps prevent or treat fractures. If you break a bone, you may need surgery to align the broken bones so that they heal correctly.

Bone deformities

It's common for Paget's disease of bone to affect the appearance of affected bones.

For example, the condition can cause:

• enlarged or misshapen bones
• the legs to curve outwards (bow legs)
• the spine to curve to the sides (scoliosis)
• the upper back to become very hunched over (kyphosis)

As with fractures, it's not clear whether bisphosphonates can help prevent deformities. If they do occur, surgery may be carried out to correct them.

Hearing loss

If Paget's disease of bone affects the skull, there's a significant risk that it could lead to permanent hearing loss and possibly total deafness.

This can occur as a result of damage to the bones or nerves that connect the ears to the brain.

It's not known whether treating Paget's disease of bone helps reduce the risk of losing your hearing, but treatment is usually recommended if the condition is affecting your skull.

Too much calcium in the blood

In rare cases, the increased cycle of bone renewal in Paget's disease of bone can result in calcium building up in the blood. This is known as hypercalcaemia.

It usually only occurs in people who have been confined to bed after an operation or a fracture.

Symptoms of hypercalcaemia can include:

• extreme tiredness
• depression
• drowsiness
• constipation
• new or worsening bone pain

Hypercalcaemia can be treated using medicines to lower blood calcium levels and slow down bone regeneration.

Heart failure

The new bone that forms in people with Paget's disease of bone often contains more blood vessels than normal bone, which can mean the heart has to work harder to pump blood around the body.

Very occasionally, the heart may not be able to pump enough blood around the body. This is known as heart failure.

Symptoms of heart failure can include:

• shortness of breath
• extreme tiredness and weakness
• swelling in the legs, ankles and feet (oedema)

Heart failure can be treated with medicine and in some cases heart surgery. Read more about how heart failure is treated.

Bone cancer

Bone cancer is a rare complication of Paget's disease of bone. It's estimated to affect between 1 in 100 and 1 in 1,000 people with the condition.

Symptoms of bone cancer are similar to those of Paget's disease of bone. They can include:

• bone pain
• swelling around the affected bone
• a lump in the affected bone

Osteosarcoma is a very serious type of cancer that can spread to other parts of the body quickly. But if it's caught early enough, it may be possible to cure it by removing the affected bone.

Read more about how bone cancer is treated.