Paget’s disease causes a malfunction in the normal process of bone remodelling. Normally, bone is continually breaking down and rebuilding. This usually slow process of bone destruction and growth is somehow altered in Paget's disease.

When an area of bone is destroyed in a person with Paget’s disease, the bone that replaces it is soft and porous. Soft bone can be weak and easily bend, leading to shortening of the affected part of the body. The bone replacement also takes place very quickly and excess bone may be formed. This can cause the bone to get larger, be painful and break easily.

The bone affected by Paget’s disease also tends to have more blood vessels than normal. This causes an increase in the blood supply to the area, and as a result the area may feel warmer than usual.

The disease can affect any bone but more commonly affects the spine, pelvis, skull, thighbone (femur – pronounced fee-mer) and shinbone (tibia – pronounced ti-bee-ah).

Paget’s disease can lead to other medical conditions including osteoarthritis, kidney stones and heart disease.

Paget’s disease is also called osteitis (pronounced ah-stee-eye-tis) deformans. It is named after Sir James Paget, an English doctor who first described the disease in 1876.

Paget’s disease is estimated to affect 3% of people over 40.  However the exact number is not known because many people who have it do not know it.  It occurs all over the world but is more prevalent in some areas, such as in Europe and Australia.

It tends to affect men more than women, and usually those over the age of 40.

In many cases, Paget's disease takes a very mild course and a person with it may not have any symptoms. Those who do have symptoms may be affected in various ways. 

If you have Paget’s disease your bones may break easily because they are weakened. Your bones may also bend, and if your leg bones are affected you may notice that your legs bow, or a leg may appear to shrink. If your spine is involved, you may feel pain in your back. If the bones in your spine bend or grow larger than usual this can put pressure on your nerves, and you may feel pain or numbness in other areas of your body also.

If Paget’s disease affects your skull, your head may increase in size from front to back. Hearing loss may result if there is involvement of some of the small bones in the middle ear or pressure is placed on the nerves related to hearing.

In late stages of the disease, your hip joint may become damaged if the bones of your pelvis have been involved.

Usually only one or a few bones are affected. However, the disease can be widespread and affect all bones. Because of the increased number of blood vessels in bones affected by Paget’s disease your heart has to work harder to pump blood to them. If many bones are affected this can cause strain on your heart and lead to other problems.

At this time there is no cure for Paget’s disease. Therefore treatment is designed to control the symptoms and change the rate of bone growth. Establishing the correct diagnosis is important because something can be done to manage most forms of arthritis and most therapies work best when started early in the disease.

Your doctor may be able to diagnose Paget's disease based on your medical history and a physical examination. Your doctor may order certain tests to help confirm the diagnosis and to determine what areas of bone are affected. These tests can include x-rays, bone scans and blood and urine tests.

A diagnosis of Paget's disease may be made when you see your doctor for another problem. You may have no symptoms at this time, but routine tests may show that you have the disease. 

Once diagnosed with Paget’s disease you may be referred to a rheumatologist or other doctor who specializes in bone disorders, or an endocrinologist, who specializes in metabolic and hormonal disorders (which affect the rates of growth in your body).

There is no cure for Paget’s disease but there are treatments that can help you manage the pain and slow the disease. Your active involvement in developing your treatment plan is essential.

Medicine

A group of prescription drugs known as bisphosphonates have been shown to be helpful in rebuilding bone, and so are used to treat Paget’s disease and other bone diseases. They reverse bone loss by causing the body to produce normal bone. The bisphosphonates often prescribed are Didronel, Fosamax and Actonel.

If you have severe pain and bone loss your doctor may prescribe a medication called calcitonin, which is given by injection. Calcitonin is a hormone that occurs naturally within the body. It helps increase bone density by affecting the levels of calcium in the blood. It reduces bone destruction and reduces the formation of new bone as well. It can also relieve pain. Often calcitonin from eel or salmon is used, as it is many times stronger than the human form.

For mild to moderate pain from Paget’s disease doctors often recommend acetaminophen (Tylenol®, Panadol®, Exdol®, etc.). Acetaminophen is a pain reliever, but has no anti-inflammatory properties, so it does not actually reduce the swelling and pressure that may be causing the pain. Because it is not an anti-inflammatory it can usually be safely taken along with most prescription medications. However, there are daily limits of acetaminophen that can be taken, so caution should be exercised, particularly if other medications that contain acetaminophen (for example, it’s found in many cold remedies) are being used. A serious overdose of acetaminophen can cause liver damage.

NSAIDs reduce pain when taken at a low dose, and relieve inflammation when taken at a higher dose. NSAIDs such as ASA (Aspirin, Anacin, etc.) and ibuprofen (Motrin IB, Advil, etc.) can be purchased without a prescription. Examples of NSAIDs that require a prescription include Naprosyn, Relafen, Indocid, Voltaren, Feldene, and Clinoril. The various NSAIDs and Aspirin®, if taken in full doses, usually have the same levels of anti-inflammatory effect. However, different individuals may experience greater relief from one medication than another. Taking more than one NSAID at a time increases the possibility of side effects, particularly stomach problems such as heartburn, ulcers and bleeding. People taking these medications should consider taking something to protect the stomach, such as misoprostol (Cytotec).

Diet

If you have Paget’s disease you should try to have a proper balance of calcium in your body. Your doctor may advise you to drink about two litres (six to eight glasses) of fluid daily to prevent other complications arising from excess calcium in your body.

Surgery

Some people with severe, advanced Paget’s disease may require surgery, though this is rare. Benefits include less pain and better movement and function.

Some kinds of surgery can repair bone deformity or rebuild part of a joint. With other kinds of surgery joints such as hips and knees can be replaced with artificial joints.

Surgery could also be required for badly fractured bones.