Paget’s Disease of Bone
Paget’s disease of bone is a chronic disease of the skeleton. In healthy bone, a process called remodeling removes old pieces of bone and replaces them with new, fresh bone. Paget’s disease causes this process to shift out of balance, resulting in new bone that is abnormally shaped, weak, and brittle. Paget’s disease most often affects older people, occurring in approximately 2 to 3 percent of the population over the age of 55. Paget’s disease is the second most common type of bone disease after osteoporosis.
If a person with Paget’s disease fractures a bone, it may take a long time to heal because of faults in the bone renewal process.
Paget’s disease tends to occur in older adults as well as people from Northern Europe. The disorder occurs in three men to every two women with Paget’s disease.
Physiology of Bone Remodeling –
In normal bone, a process called remodeling takes place every day. Bone is absorbed and then reformed in response to the normal stresses on the skeleton. More specifically:
• Cells of the bone called “osteoclasts” absorb bone.
• Cells of the bone called “osteoblasts” make new bone.
In Paget’s disease, osteoclasts are more active than osteoblasts. This means that there is more bone absorption than normal. The osteoblasts try to keep up by making new bone, but they overreact and make excess bone that is abnormally large, deformed, and fits together haphazardly.
Normal bone has a tight overlapping structure, like a well-constructed brick wall. Bone afflicted by Paget’s disease has an irregular mosaic pattern, as though the bricks were just dumped in place. The end result is bones that are large and dense, but weak and brittle. The bone is prone to fractures, bowing, and deformities.
Many people are not aware that they have Paget’s disease because they do not experience symptoms. They might also mistake any symptoms for other bone disorders, such as arthritis.
The most common symptoms that occur relate to bone or joint pain. Other symptoms includes –
• swelling of joints
• tenderness, or redness of the skin that covers the areas affected by Paget’s disease.
Some people only become aware of their presentation of Paget’s disease after experiencing a fracture in a weakened bone.
The disease might affect only one or two areas of your body or might be widespread. Your signs and symptoms, if any, will depend on the affected part of your body.
• Pelvis. Paget’s disease of bone in the pelvis can cause hip pain.
• Skull. An overgrowth of bone in the skull can cause hearing loss or headaches.
• Spine. If your spine is affected, nerve roots can become compressed. This can cause pain, tingling and numbness in an arm or leg.
• Leg. As the bones weaken, they may bend — causing you to become bowlegged. Enlarged and misshapen bones in your legs can put extra stress on nearby joints, which may cause osteoarthritis in your knee or hip.
Causes and Risk Factors –
The cause of Paget’s disease is not known, but doctors have identified a number of risk factors that make someone more likely to develop the disease. These include:
Paget’s disease tends to run in families. In as many as 25 to 40 percent of cases, another relative will also have the disease.
Paget’s disease occurs only rarely in people under 40 years of age. It is more common as people age.
It is more common in people of Anglo-Saxon descent and those who live in certain geographic areas, such as the United States, England, Australia, New Zealand, and Western Europe. It is not common in Scandinavia, China, Japan, or India.
• Environmental factors.
Some studies suggest that certain environmental exposures may play a role in the development of Paget’s disease. This has not been proven definitively, however.
In most cases, Paget’s disease of bone progresses slowly. The disease can be managed effectively in nearly all people. Possible complications include:
• Fractures and deformities.
Affected bones break more easily, and extra blood vessels in these deformed bones cause them to bleed more during repair surgeries. Leg bones can bow, which can affect your ability to walk.
Misshapen bones can increase the amount of stress on nearby joints, which can cause osteoarthritis.
• Neurological problems.
When Paget’s disease of bone occurs in an area where nerves pass through the bone, such as the spine and skull, the overgrowth of bone can compress and damage the nerve, causing pain, weakness or tingling in an arm or leg or hearing loss.
• Heart failure.
In severe cases, your heart may have to work harder to pump blood to the affected areas of your body. Sometimes, this increased workload can lead to heart failure.
• Bone cancer.
Bone cancer occurs in up to 1% of people with Paget’s disease of bone.
Your health care provider may use many tools to make a diagnosis:
• A medical history, which includes asking about your symptoms
• A physical exam
• An x-ray of the affected bones. Paget’s disease is almost always diagnosed using x-rays.
• An alkaline phosphatase blood test
• A bone scan
Sometimes the disease is found by accident when one of these tests is done for another reason.
If you don’t have symptoms, you might not need treatment. However, if the disease is active – indicated by an elevated alkaline phosphatase level – and is affecting high-risk sites in your body, such as your skull or spine, your doctor might recommend treatment to prevent complications, even if you don’t have symptoms.
If symptoms do occur, your doctor may recommend one or more nonsurgical treatments.
• Nonsteroidal anti-inflammatory drugs (NSAIDs).
Medications such as ibuprofen, naproxen and aspirin can help relieve mild bone pain that arises from Paget’s disease or from arthritis that may be associated with the disease.
• Assistive devices.
If your pelvis or leg is affected by the disease, using a cane can help relieve pain by decreasing the forces going through the bone. Using a cane can also help prevent falls, so there is less risk of fracture in the bone—a common complication of Paget’s disease.
Wearing a brace can help relieve pain by preventing malalignment of the affected bones.
• Biphosphates therapy
Osteoporosis drugs (bisphosphonates) are the most common treatment for Paget’s disease of bone. Bisphosphonates are typically given by injection into a vein, but they can also be taken by mouth. When taken orally, bisphosphonates are generally well tolerated but can irritate the stomach.
Bisphosphonates that are given intravenously include:
• Zoledronic acid (Zometa, Reclast)
• Pamidronate (Aredia)
• Ibandronate (Boniva)
• Alendronate (Fosamax, Binosto)
• Risedronate (Actonel, Atelvia)
• Other option
If you can’t tolerate bisphosphonates, your doctor might prescribe calcitonin (Miacalcin), a naturally occurring hormone involved in calcium regulation and bone metabolism. Calcitonin is a drug that you administer to yourself by injection or nasal spray. Side effects may include nausea, facial flushing and irritation at the injection site.
In rare cases, surgery might be required to:
• Help fractures heal
• Replace joints damaged by severe arthritis
• Realign deformed bones
• Reduce pressure on nerves
Paget’s disease of bone often causes the body to produce too many blood vessels in the affected bones, increasing the risk of serious blood loss during an operation.
Lifestyle Changes –
To reduce your risk of complications associated with Paget’s disease of bone, try these tips:
• Prevent falls.
Paget’s disease of bone puts you at high risk of bone fractures. Ask your doctor for advice on preventing falls. He or she may recommend that you use a cane or a walker.
• Fall-proof your home.
Remove slippery floor coverings, use nonskid mats in your bathtub or shower, tuck away cords, and install handrails on stairways and grab bars in your bathroom.
• Eat well.
Be sure your diet includes adequate levels of calcium and vitamin D, which helps bones absorb calcium. This is especially important if you’re taking a bisphosphonate. Review your diet with your doctor and ask if you should take vitamin and calcium supplements.
• Exercise regularly.
Regular exercise is essential for maintaining joint mobility and bone strength. Talk to your doctor before beginning an exercise program to determine the right type, duration and intensity of exercise for you. Some activities may place too much stress on your affected bones.
For more informative articles on health related issues, please visit our website www.santripty.com and also feel free to consult.