What Is Paget's Disease of Bone?

Medically Reviewed by David Zelman, MD on November 02, 2022
4 min read

Your body constantly builds new bone to replace the old. But with Paget's disease, this happens too fast and gives your bones an odd shape. They may be bent, weak, brittle, soft, or too big. The new bones also may not fit together as tightly as they should.

The disease usually affects your pelvis, skull, spine, and legs, but it can happen in any bone. It may cause your bones to break and can lead to other health problems. For example, your bones may press on nerves or lead to arthritis.

Paget's disease affects people older than 40, and your chances of getting it go up as you age. About a million people in the U.S. have it -- men more often than women.

Doctors don't really know what causes Paget's disease. It may be a viral infection of the bone, or it could be caused by something in the environment. In about 15% to 30% of cases, there's a family history of Paget's. Researchers have found a few genes that can make it more likely that you or a family member will get it. Smoking may also increase your chances.

If you have family members with it, you should get a blood test every 2 to 3 years after age 40.

The symptoms appear slowly over time, and the majority of people have no symptoms and don't know they have Paget's. It's generally discovered through lab tests or shows up on xrays. Bone pain is common. Some people also get arthritis in joints near the affected bones. They are more at risk of breaking the affected (and weakened) bone.

If your skull is involved, you could have headaches, vision problems, hearing loss, pain in your face, and numbness or tingling.

Sometimes you can see the bone changes. Your legs and thighs may look larger than usual and may seem bent or bowed. Your forehead can look bigger, too. If Paget's gets worse, you may waddle when you walk.

In rare cases, serious pain means the Paget's has led to bone cancer. Other rare problems include congestive heart failure (where your heart doesn't pump enough blood to meet your body's needs) and pressure on the tissue of your brain.

Paget's can be hard to diagnose. It can be confused with arthritis, osteoporosis, spinal stenosis, or other changes that come with age. Some people only find out they have it because of an X-ray or blood test taken for a different reason.

The doctor may ask you to take blood tests to look for an enzyme known as ALP (alkaline phosphatase) in your blood. People who have Paget's often have more of this enzyme than normal, which reflects the bone turnover that is common in Paget's. 

To see if you have Paget's disease of bone, your doctor will examine you and ask questions about your family history. They'll want pictures taken of your bones, because a bone with Paget's will look larger and thicker than usual. It can look like it didn't grow right. This will be done with an elevated Alk Phos on a routine blood test, xrays that are suspicious for Pagets, or one of the following:

  • Bone scan: A small amount of a radioactive substance, called a tracer, is put into a vein in your arm. It goes through your bloodstream and into your bones. A special camera takes pictures of your bones and any areas that absorb too much or too little of the tracer can be a sign of a problem with the bone. A bone scan is somewhat better than xray for diagnosis, especially early on. It also shows the extent of paget lesions in your bones cause it is not targeted at specific bones (like an xray).
  • MRI (magnetic resonance imaging): Powerful magnets and radio waves are used to make detailed images of your bones. It is alsoi helpful in detrnmining if there is osteosarcoma or a bone malignancy which Pagets put you at risk for. 
  • CT (computerized tomography) scan: Several X-rays are taken from different angles and put together to make a more complete picture of your bones. It,too, can dtect osteosarcoma.

Depending on the parts of your body that are affected, you may need to see more than one doctor, including those who treat bone disease, joint problems, nerve problems, and conditions of the ears, nose, and throat.

There's no way to fix the changes that have already happened, such as hearing loss or deformed bones, but you can get help with the issues caused by Paget's. Options include:

  • Physical help, like wedges in your shoe, a cane for walking, physical therapy, and other ways to build muscle that can help control pain
  • Medicines like bisphosphonates to prevent bone loss or calcitonin to control calcium level
  • Medicine to help with the pain (acetaminophen like Tylenol or NSAIDs like ibuprofen or Advil)

Your doctor may suggest surgery to fix a broken or deformed bone, replace a hip or knee, or treat severe arthritis.

Ask your doctor about ways to keep your bones healthy. Here are a few tips:

  • Take calcium and vitamin D supplements.
  • Get regular exercise.
  • Don't put lots of stress on the affected bones.
  • Use a splint if a certain bone is at risk for breaking.