This information is for people who have Paget’s disease of the bone, or who would like information about it.

Paget’s disease of the bone is a long-term benign (non-cancerous) condition. The bone stops forming in the normal way causing weakness which can result in pain and re-shaped bones in the leg or arm. In many cases Paget’s disease causes no symptoms at all and is picked up by chance on an X-ray.

• About Paget’s disease of bone
• Symptoms of Paget’s disease of bone
• Cause of Paget’s disease of bone
• Complications of Paget’s disease of bone
• Diagnosis of Paget’s disease of bone
• Treatment of Paget’s disease of bone

About Paget’s disease of bone

Bone

Bone is a living tissue. It’s made up of a mineral called calcium and different types of cells. The cells continuously break down the old matrix and form new bone matrix. Most bones contain a type of soft tissue called bone-marrow in their centre that produces blood cells.

At joints such as the elbow or the knee, bones are covered with a thick rubbery tissue called cartilage. Cartilage allows smooth movement at the joints without damage to the bone.

As well as supporting the body, some bones, for example, the skull and the ribcage, protect important organs from external damage.

What is Paget’s disease of bone?

Paget’s disease of bone occurs when the breakdown of the old matrix and the new matrix speeds up; which can be up to 40 times as fast. This causes the bone to form differently so it is more vulnerable to fracture. The most affected areas are usually the pelvis, thigh bone (femur), lower spine, skull and shin bone (tibia).

Nerves can become compressed because of the change in structure. The increase in activity also increases blood to the bone which can affect sensitivity of the nerves causing aching or pain.

Paget’s disease of bone is common and affects about one or two in every 100 European Caucasian adults. It’s much less common in people of other types of descent. It’s more likely if you’re over 55 and is three times as common in men as in women.

Symptoms of Paget’s disease of bone

If you have Paget’s disease of bone you may not have any symptoms. Only around one in 20 people have symptoms.

If you do have symptoms you may have the following:

• bone pain when you are resting or at night, or when moving the area
• joint pain
• leg shape change
• head shape change
• numbness or tremor in the nerves of the head
• pain or numbness in the back

If you also have osteoarthritis, you may have more symptoms or they may be worse.

Cause of Paget’s disease of bone

Paget’s disease of bone is a progressive bone disease that doesn’t have a known cause. It’s thought to be inherited. This means that it’s passed from parent to child and is caused by a gene in your genetic make-up which either makes you more susceptible to developing it or the symptoms show themselves as you get older. There is, however, no clear pattern of inheritance. So if you have it that doesn’t mean that your children will too.

Other possible causes of Paget’s disease of bone include a viral infection which may infect the bone earlier in life slowly causing Paget’s disease of bone. Environmental factors such as not getting enough calcium in your diet may be a cause or contribute to developing it. It has been suggested that lifting or carrying heavy items may affect the bones of your skeleton, making you more vulnerable to Paget’s disease of bone.

Complications of Paget’s disease of bone

There are a number of complications which can occur as a result of Paget’s disease of bone.

Bone deformity

The long bones in the body such as the leg or arm can permanently curve or bow which changes the shape of your arm or leg.

Osteoarthritis

This usually affects the joints and can cause pain in the knee or hip joints. The cartilage on joints wears and thins so the bone beneath the cartilage thickens and forms outgrowths called osteophytes which make your joint roughened with small protrusions. The knee joint may also appear enlarged as the area around the knee thickens and becomes inflamed. Most people with osteoarthritis don’t have Paget’s disease, but if Paget’s disease affects a joint eg the hip joint then the risk of osteoarthritis is increased. This is because of repeated stress on the joints which have Paget’s disease.

Pathological fracture

Sometimes this is due to a cyst developing in the area of the bone with Paget’s disease, but very rarely, a growth or malignant (cancerous) tumour can develop on the bone which causes it to fracture.

Nerve compression

If this occurs, it’s generally in the head and neck and can lead to hearing problems such as tinnitus, hearing loss and deafness. It can also cause dizziness. In some areas of the skull nerves pass through an opening or passage within the bone which can put pressure on the nerve if the skull changes in shape. This can also occur in the spine (spinal stenosis) causing back pain.

Rare complications include the following.

• Hypercalcaemia, when the blood calcium levels increase, can be a complication of Paget’s disease of bone. This can cause additional symptoms such as tiredness, weight loss and constipation.
• Compression of areas of bone can cause fluid in the spine and head to build up causing hydrocephalus. Decreased mental ability and convulsions are symptoms.
• Rarely the nerves in the legs can be affected causing paralysis.
• Heart failure can occur as the increase in blood flowing to the bone can reduce that which is available to the rest of the body. Breathlessness and increased pulse are symptoms.
• Sometimes a benign (non-cancerous) tumour that forms on the bone can become cancerous.
• Pain and swelling of the joint called gout can also occur.

Diagnosis of Paget’s disease of bone

Paget’s disease may be diagnosed when you are having an X-ray for another condition.

If your doctor is concerned that you may have Paget’s disease, you may also have a CT (computed tomography) scan if an X-ray isn’t clear.

A bone scan may be used to detect Paget’s disease if an X-ray or CT scan can’t confirm the diagnosis. This is when a harmless radioactive substance called an isotope is injected into the body, and a machine scans the bone to see where the isotope is absorbed as these may be areas of Paget’s disease.

A blood test may be taken to check the levels of calcium or an enzyme called alkaline phosphatase in the blood which can indicate Paget’s disease.

A bone biopsy is only taken if Paget’s disease of the bone can’t be confirmed using other methods of diagnosis. This is when a small sample of bone is taken from the area to test for Paget’s disease.

Treatment of Paget’s disease of bone

Treatment aims to reduce pain and limit the changes which can occur to the bones.

Medicines

You may be given bisphosphonates. These slow the rate at which the bone matrix forms and breaks down reducing the rate of turnover, preventing the bone from changing and regulating bone structure. They also reduce bone pain and promote healing.

You may be given an intravenous drip for some medicine.

Side-effects of bisphosphonates include feeling sick, diarrhoea, feeling generally unwell and a temperature.

Painkillers or non-steroidal anti-inflammatory drugs (NSAIDS) can be taken for any pain you may have.

Always read the instruction leaflet which comes with your medicine.

Surgery

Surgery isn’t usually necessary, but you may need surgery to repair a fracture which may be fixed using a plate or pins in the bone.

Joint replacement surgery may be advised with advanced osteoarthritis if you find medication doesn’t help.

Sometimes if a nerve is compressed you may need to have surgery to relieve the nerve compression and reduce pain.

Osteotomy, when part of the bone is cut and the bone reshaped may be done if the bone is severely curved.

Additional support

Walking sticks, walking frames, shoe raises may be given to help you adjust if Paget’s disease causes one leg to be slightly shorter than the other or you have any problems walking.