Questions and Answers about Paget's Disease of Bone

November 2011

This booklet contains general information about Paget's disease of bone. It describes what Paget's disease is, its causes, and treatment options. Highlights of current research are also included. If you have further questions, you may wish to discuss them with your health care provider.

What Is Paget's Disease of Bone?

Paget's disease of bone is a chronic disorder in which excessive breakdown and formation of bone tissue can lead to bone enlargement, weakening, and fractures, as well as pain and arthritis in the joints near the affected bones (see box "Bone Biology").

Information Boxes

Unlike some other bone diseases, which affect all of the bones of the body, Paget’s disease typically affects just one or a few bones. The most commonly affected bones are those of the pelvis, skull, spine, and legs.

A less common form of Paget’s disease, called early-onset familial Paget’s disease of bone, shows up in a person’s teens or twenties. The early-onset form is similar to the classic form of the disorder except that it is more likely to affect the skull, spine, ribs, and small bones of the hands. It is also associated with hearing loss early in life.


Bone Biology

Just because you have stopped growing taller, doesn’t mean your bones have stopped growing. Bone is living tissue that goes through a constant process of growth and renewal, called remodeling. This process, which is designed to supply the body with strong, healthy bone for a lifetime, occurs in two stages: bone resorption and bone formation. During resorption, cells called osteoclasts on the bones’ surface absorb old bone, creating small holes in the bone. During formation, the holes are systematically filled by bone-forming cells called osteoblasts.

When the process is working as it should, resorption and formation are balanced and responsive to the stresses placed on the bone. Much like muscles, bones that are worked grow stronger to meet the demands placed on them.

In Paget’s disease, however, this process is disrupted. Early in the disease process, bone resorption begins to outpace bone formation—old bone breaks down faster than new bone is built. Over time, your body overcompensates by speeding up bone formation. The new bone that is formed is abnormally large, weak, brittle, and prone to fractures.


What Are the Symptoms of Paget’s Disease?

For many people, Paget’s disease causes no symptoms. Some people have symptoms, but attribute them to other causes. Often people don’t realize they have the disease until they see a doctor about complications from it. Symptoms, when they occur, can include:

  • Pain, which may occur in any of the bones affected by the disease. Pain may also occur in the joints close to the affected bone, if changes in the bone affect joint function or put excess stress on the joints.
  • Headaches and hearing loss, caused by involvement of the skull or, in the case of hearing loss, the bone surrounding the inner ear.
  • Tingling and numbness in arms and legs, due to pressure on nerves caused by enlarged vertebrae.
  • Bone changes, such as increased head size, bowing of a limb, or curvature of the spine.

Symptoms get worse slowly, and the disease does not spread to other bones.


Beyond Bones: How Other Parts of the Body Can Be Affected by Paget’s Disease

Although Paget’s is a disease of bone, its complications can affect other body parts and functions, as well. Following are some of the possible complications.

  • Joint damage. Involvement of the bones can put stress on nearby joints causing the joint cartilage to break down. This can lead to osteoarthritis, a form of joint disease in which the cartilage wears away, leading to pain, stiffness, and the formation of bony outgrowths called spurs.
  • Heart failure. If Paget’s disease is extensive, the heart may have to work harder to pump blood to the affected areas. For people who have pre-existing heart disease, this added work can lead to heart failure, a condition in which the heart is unable to deliver enough blood to meet the body’s needs.
  • Hearing or vision loss. When Paget’s disease affects the skull and bone surrounding the inner ear, hearing loss may occur in one or both ears. In rare cases, skull involvement may affect the nerves to the eyes, causing some loss of vision.
  • Kidney stones. Kidney stones, which are rock-like masses of minerals, primarily calcium, that form in the urinary tract, are more common in Paget’s disease. Drinking a lot of water may help prevent them.
  • Pinched nerves. When Paget’s disease affects the bones of the spine (vertebra), the excess growth can pinch the nerves in the spinal column. This can lead to shooting pain, numbness, or tingling in the extremities.
  • Dental problems. If Paget’s disease affects the facial bones, this can lead to loosening of the teeth and potential tooth loss.

Who Gets Paget’s Disease?

Uncommon in people under age 40, Paget’s disease grows more common with age. The condition is more common in people of Anglo-Saxon descent in certain geographical areas including England, the United States, Australia, New Zealand, and Western Europe. It is not common in Scandinavia, China, Japan, or India.

Paget’s disease tends to occur in families. Research suggests that having a close relative with Paget’s disease makes you 7 to 10 times more likely to develop the disorder than someone without an affected relative.

What Causes Paget’s Disease?

Doctors do not know the exact cause of Paget’s disease, but the fact that the condition tends to run in families suggests that genes play a role. Several genes have been identified that appear to increase a person’s chances of having the disease.

However, genes alone are unlikely to cause the disorder. Though it has not been proven definitively, many doctors believe that something in the environment contributes to the development of Paget’s disease in people who are genetically predisposed. Some scientists are studying the possibility that a slow-acting virus may cause Paget’s disease.

How Is Paget’s Disease Diagnosed?

A diagnosis of Paget’s disease is often made or confirmed by x ray. X rays of bone affected by Paget’s often show characteristic features. These may include a classical v-shaped pattern between healthy and diseased long bones, known as the blade of grass lesion, and patches of bone thickening, typically in the skull, referred to as the cotton wool pattern because of its poorly defined and fluffy appearance on x ray.

Other tests used in the diagnosis of Paget’s disease are:

Alkaline phosphatase blood test. This test is used to measure levels of serum alkaline phosphatase (SAP), a type of enzyme made by bone cells and overproduced by bones affected by Paget’s disease. Although there are several possible causes for a mild elevation in SAP, a level that is greater than twice the usual level strongly suggests Paget’s.

Bone scan. A bone scan is a test in which a small amount of radioactive dye is injected into a vein in the arm. The dye circulates through the bloodstream and collects in areas where there is increased blood flow and activity of bone-forming cells characteristic of Paget’s disease. A special camera scans the bones, detecting areas where the dye has collected. If a scan suggests Paget’s disease, x rays may be used to confirm the diagnosis. Bone scans may also be used to determine the extent and activity of the disorder.

Bone biopsy. In rare cases, doctors remove a small sample of bone (called a biopsy) and examine it under a microscope. Biopsies may be performed if x rays fail to confirm or refute a Paget’s diagnosis. Biopsies may also be used to rule out bone cancer.

What Type of Doctor Diagnoses and Treats Paget’s Disease?

Paget’s disease is often diagnosed and treated by endocrinologists or rheumatologists. Endocrinologists are doctors who specialize in diagnosing and treating hormonal conditions. Rheumatologists are doctors who specialize in disorders of the joints, connective tissues, and muscles.

Other doctors may treat different specific symptoms or complications of Paget’s disease. These include:

  • Orthopaedic surgeons, who specialize in diagnosing, treating, and preventing injuries and disorders of the musculoskeletal system, which includes bones, joints, ligaments, muscles, nerves, and tendons.
  • Neurologists, who are trained to diagnose and treat disorders of the nervous system, which includes the brain, spinal cord, nerves, and muscles.
  • Otolaryngologists, who specialize in conditions of the ear, nose, and throat.

What Is the Treatment for Paget’s Disease?

The goals of Paget’s disease treatment are to control excessive bone breakdown and formation, reduce the risk of complications, and ease bone and joint pain. In more severe, advanced cases it may also involve repairing fractures, correcting bone deformity, and replacing joints damaged by the disease. Treatment includes the following:

Medications

Several types of medications may be used in Paget’s disease treatment. They include:

  • Bisphosphonates. The most commonly used medications for Paget’s disease are drugs from a class called bisphosphonates. Used to treat a variety of bone diseases, bisphosphonates work by controlling the excessive bone breakdown and formation that occurs in Paget’s disease. A number of bisphosphonates are FDA-approved for treating the disorder. Depending on the bisphosphonate prescribed, you may take it by mouth in a tablet form or through an intravenous (IV) infusion in your doctor’s office.
  • Calcitonin. Derived from salmon, calcitonin is similar to a hormone made by the thyroid gland that regulates blood levels of calcium and phosphate and promotes the formation of new bone. Calcitonin approved to treat Paget’s disease is available by injection. Although less effective and less commonly used than bisphosphonates, calcitonin may be appropriate for certain patients.

Pain Relievers

Several over-the-counter (OTC) medications may help ease the pain associated with Paget’s disease. These include aspirin, acetaminophen, ibuprofen,1 and naproxen. For more severe pain that does not respond to OTC medications, doctors may recommend a prescription pain reliever.

1 Warning: NSAIDs can cause stomach irritation or, less often, they can affect kidney function. The longer a person uses NSAIDs, the more likely he or she is to have side effects, ranging from mild to serious. Many other drugs cannot be taken when a patient is being treated with NSAIDs, because NSAIDs alter the way the body uses or eliminates these other drugs. Check with your health care provider or pharmacist before you take NSAIDs. Also, NSAIDs sometimes are associated with serious gastrointestinal problems, including ulcers, bleeding, and perforation of the stomach or intestine. People over age 65 and those with any history of ulcers or gastrointestinal bleeding should use NSAIDs with caution.

Surgery

Although medications can often regulate bone growth and minimize complications, surgery may be necessary to correct problems that result from irregular bone growth, including:

  • Fractures. If fractures are displaced, meaning the ends of the bones where the break occurred are no longer aligned, surgery may be necessary to position the bones so they can heal.
  • Arthritis. If changes in the bones place stress on adjacent joints, the cartilage that normally cushions the ends of the bones can wear away, leaving bone rubbing against bone. When this occurs, surgery to replace the damaged joint with an artificial one may ease pain and decrease disability. Hips and knees are the most commonly replaced joints.
  • Bone deformity. When changes in a bone place added stress on a weight-bearing joint, a surgeon may perform a procedure called an osteotomy. This procedure, which involves cutting and realigning a bone, can be useful for reducing pain in the affected joint, usually a knee.
  • Pinched nerves. Less commonly, a doctor may do surgery to remove bone overgrowth that is pinching a nerve in the spine. Because blood flow to the bones can be increased in Paget’s disease, medical treatment may be needed to decrease bleeding before surgery. You should discuss any needed medical treatment with your doctor before planning surgery.

Besides Medical Treatment, What Can I Do to Help Prevent Complications?

Aside from following your doctor’s prescribed treatment, there are things you can do to be healthier and help reduce risk of complications. Here are some to do now:

  • Eat well. Although there is no special diet to prevent or treat Paget’s disease, a healthy diet is important for good health. It is important for your diet to include adequate amounts of calcium and vitamin D, which helps your bones use calcium. Calcium and vitamin D needs change during your lifetime (see table “Recommended Intakes for Calcium and Vitamin D”). If you are uncertain whether you are getting enough calcium and vitamin D, speak with your doctor, who may recommend calcium and/ or vitamin D supplements. If you have a history of kidney stones, you should also discuss calcium and vitamin D intake with your doctor.

Recommended Calcium and Vitamin D Intakes

Life-stage group Calcium mg/day Vitamin D (IU/day)
Infants 0 to 6 months 200 400
Infants 6 to 12 months 260 400
1 to 3 years old 700 600
4 to 8 years old 1,000 600
9 to 13 years old 1,300 600
14 to 18 years old 1,300 600
19 to 30 years old 1,000 600
31 to 50 years old 1,000 600
51- to 70-year-old males 1,000 600
51- to 70-year-old females 1,200 600
>70 years old 1,200 800
14 to 18 years old, pregnant/lactating 1,300 600
19 to 50 years old, pregnant/lactating 1,000 600

Definitions: mg = milligrams; IU = International Units
Source: Food and Nutrition Board, Institute of Medicine, National Academy of Sciences, 2010.


  • Exercise regularly. Regular physical activity is important for building strong muscles and bones, maintaining joint mobility, and improving balance and coordination. To build strong bones, you must get plenty of weight-bearing exercise, or exercise in which the legs bear the body’s weight. Walking, jogging, jumping rope, and dancing are examples of weight-bearing exercise. Strength training is important to strengthen the muscles that support the joints. Exercises that promote balance and coordination, such as Tai Chi, can help reduce your risk of falling and breaking a bone. Your doctor or a physical therapist can help you develop an exercise plan that provides the benefits you need without stressing affected bones.
  • Maintain a healthy weight. Maintaining a healthy weight is particularly important if Paget’s has led to arthritis of the weight-bearing joints, such as the hip or knee. Excess weight can mean more stress—and pain—for affected joints.
  • Avoid falls. When Paget’s disease causes bones to be fragile, even a minor fall can cause a painful fracture. Although exercising to improve muscle strength, balance, and coordination is one of the best ways to reduce your risk of falling, your doctor can give you other advice for preventing falls. This may include walking with a cane or walker and taking steps to make your home safer, such as:
    • installing grab bars and using nonskid mats in your tub or shower
    • placing items you use frequently on low shelves to avoid the need to climb or use a step stool
    • securing or removing throw rugs, power cords, and other items that could cause you to trip
    • installing hand rails on stairways and lights in stairways and hallways.
  • Seek support. Although it is important to take care of yourself physically when you have Paget’s disease, it is important to take care of yourself emotionally, too. Living with a chronic disease can be stressful. Many people with chronic diseases like Paget’s find it helpful to speak with a social worker, counselor, or other mental health professional, or with other people who have the same condition. Your doctor will be able to help you find a counselor who works with people with chronic diseases or may be able to direct you to a support group.

What Is the Prognosis for People Who Have Paget’s Disease?

Paget’s disease is rarely fatal. For most people with the disorder, the prognosis is good, particularly if they begin treatment before major changes have occurred in the affected bones. Because early diagnosis and treatment is important to minimize complications, doctors may recommend that family members of people with Paget’s disease (who face an increased risk of the disorder themselves) have an alkaline phosphatase blood test every 2 to 3 years beginning around age 40. If the level is elevated, suggesting possible Paget’s disease, bone scans or x rays may be used to verify the diagnosis, so that treatment can begin early in the disease process. Although treatment is effective at controlling symptoms and minimizing the risk of complications, it cannot cure Paget’s disease. A small percentage of people with Paget’s disease—perhaps less than 1 in 1,000—develop a rare type of bone cancer called osteosarcoma, which may be treated with surgery, radiation, and/or chemotherapy.

What Research Is Being Conducted to Help People Who Have Paget’s Disease?

Researchers are working to identify the most effective and safe treatments for Paget’s disease and looking for new targets for drug therapy. Researchers are also beginning to target factors that link bone resorption (or breakdown) and bone formation, two processes that must work in concert to provide us with healthy bones (see box “Bone Biology”). In Paget’s disease, the processes of bone resorption and formation remain coupled, but both proceed at abnormally high rates, producing excessive bone of poor quality. Scientists are also continuing to examine the causes and mechanisms of Paget’s disease, including the genes that are involved. Identifying and better understanding the genes involved in the disease could help doctors predict who may be at risk for it and could lead to the development of specific therapies not only to slow damage, but perhaps to stop and could even reverse the damage. The role of environmental factors—such as viruses—in the development of Paget’s is just beginning to be clarified. Researchers are exploring whether such factors contribute to the development of the disease in people who are genetically predisposed.

Where Can People Find More Information About Paget’s Disease?

NIH Osteoporosis and Related Bone Diseases ~ National Resource Center

2 AMS Circle
Bethesda,  MD 20892-3676
Phone: 202-223-0344
Toll Free: 800-624-BONE (2663)
TTY: 202-466-4315
Fax: 202-293-2356
Email: NIHBoneInfo@mail.nih.gov
Website: http://www.bones.nih.gov

Other Resources

American Academy of Orthopaedic Surgeons

Website: http://www.aaos.org

American College of Rheumatology

Website: http://www.rheumatology.org

The Paget Foundation for Paget’s Disease of Bone and Related Disorders

Website: http://www.paget.org

Key Words

Alkaline phosphatase blood test. A test that measures blood levels of an enzyme made by bone cells and overproduced by bones affected by Paget’s disease. A highly elevated level of this enzyme may indicate a diagnosis of the disorder.

Bisphosphonates. A type of medication that works to control excessive bone breakdown and formation that occurs in Paget’s disease. Bisphosphonates are commonly used medications to treat Paget’s disease.

Blade of grass lesion. A v-shaped pattern between healthy and diseased long bones that may show up on x rays in people with Paget’s disease. The presence of the pattern is useful in diagnosing the disorder.

Bone biopsy. A test in which a small sample of bone is removed and examined under a microscope. Biopsies are sometimes used to confirm a diagnosis of Paget’s disease or to rule out bone cancer.

Bone scan. A test in which a small amount of radioactive dye is injected into a vein in the arm and allowed to circulate through the bloodstream. A special camera is then used to scan the bones and detect areas of increased blood flow or bone-forming cells. Bone scans may be used to diagnose Paget’s disease and to determine its extent and activity.

Calcitonin. A medication derived from salmon. It is similar to a hormone made by the thyroid gland that regulates blood 18 levels of calcium and phosphate and promotes the formation of new bone. It is sometimes used in Paget’s disease treatment.

Cotton wool appearance. A fluffy, poorly defined patch on an x ray, typically of the skull, due to bone thickening. Its appearance is useful in the diagnosis of Paget’s disease.

Endocrinologist. A doctor who specializes in the diagnosis and treatment of conditions involving hormones and metabolism. Endocrinologists commonly treat Paget’s disease.

Heart failure. A condition in which the heart is unable to deliver enough blood to meet the body’s needs. In people with extensive Paget’s disease, the heart may have to work harder to pump blood to affected areas of the body. If the heart is already damaged, the increased workload may lead to heart failure.

Osteoarthritis. A joint disease that occurs when the cartilage that cushions the ends of the bones where they meet to form joints wears away, leading to pain, stiffness, and the formation of bony outgrowths called spurs. Osteoarthritis is a common long-term complication of Paget’s disease.

Osteoblasts. Bone-forming cells. In Paget’s disease, overactivity of osteoblasts leads to bone that is abnormally large, weak, and brittle.

Osteoclasts. Cells on the bones’ surfaces that absorb old bone, creating small holes in the bone to be filled by bone-forming cells called osteoblasts.

Orthopaedic surgeon. A doctor who specializes in the diagnosis, treatment, and prevention of injuries, disorders, and diseases of the musculoskeletal system, which includes bones, joints, ligaments, muscles, nerves, and tendons.

Osteosarcoma. A rare type of bone cancer that can occur as a complication of Paget’s disease. It is estimated to affect less than 1 in 1,000 patients with Paget’s disease.

Otolaryngologists. Doctors who specialize in the diagnosis and treatment of conditions of the ear, nose, and throat. People with Paget’s disease may see an otolaryngologist for some of the complications of their disease.

Rheumatologists. Doctors who specialize in diagnosing and treating disorders of the joints and muscles.

X ray. A test in which an x-ray beam is passed through the body to create a two-dimensional picture of the bones. X rays are used to diagnose Paget’s disease.

Acknowledgments

The NIAMS gratefully acknowledges the assistance of the following individuals in the preparation and review this booklet: Kenneth W. Lyles, M.D., Professor of Medicine, Duke University and VA Medical Centers, Durham, NC; G. David Roodman, M.D., Ph.D., Professor of Medicine and Vice Chair for Research, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA; Charlene Waldman, Executive Director, The Paget Foundation, New York; Joan A. McGowan, Ph.D., Director, Division of Musculoskeletal Diseases, NIAMS; and William J. Sharrock, Ph.D., Director, Integrated Physiology and Genetics of Bone Program, Division of Musculoskeletal Diseases, NIAMS.

For Your Information

This publication may contain information about medications used to treat the health condition discussed here. When this publication was produced, we included the most up-to-date (accurate) information available. Occasionally, new information on medication is released.

For updates and for any questions about any medications you are taking, please contact:

U.S. Food and Drug Administration

Website: http://www.fda.gov
Toll free: 888–INFO–FDA (888–463–6332)

For updates and questions about statistics, please contact:

Centers for Disease Control and Prevention’s National Center for Health Statistics

Website: http://www.cdc.gov/nchs
Toll free: 800–232–4636

NIH Publication No. 10-7670

NIH Osteoporosis and Related Bone Diseases ~ National Resource Center

2 AMS Circle
Bethesda,  MD 20892-3676
Phone: 202-223-0344
Toll Free: 800-624-BONE (2663)
TTY: 202-466-4315
Fax: 202-293-2356
Email: NIHBoneInfo@mail.nih.gov
Website: http://www.bones.nih.gov

The NIH Osteoporosis and Related Bone Diseases ~ National Resource Center provides patients, health professionals, and the public with an important link to resources and information on metabolic bone diseases. The mission of NIH ORBD~NRC is to expand awareness and enhance knowledge and understanding of the prevention, early detection, and treatment of these diseases as well as strategies for coping with them.

The NIH Osteoporosis and Related Bone Diseases ~ National Resource Center is supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases with contributions from:

The National Institutes of Health (NIH) is a component of the U.S. Department of Health and Human Services (DHHS).


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