Paget’s Disease of Bone – Symptoms, Causes and Treatment

Paget’s disease is a localized disorder of bone characterized by the disruption in normal bone remodeling. To understand the mechanism of development of Paget’s disease, one must know what exactly is bone remodeling. Bone remodeling in simpler terms can be called as bone metabolism. Our bone is an active tissue. New bones are constantly being formed, while old bones are continually being destroyed. Now, the question arises, what forms the bone and what destroys it? The bone-forming cells are known as Osteoblasts, and the bone-resorbing cells are known as Osteoclasts. In a healthy individual, the processes of bone formation and destruction are in harmony, thus maintaining a normal bone turnover.

In Paget’s disease, initially, there is overactivity of osteoclasts, which causes an increased bone destruction. This is followed by a compensatory overactivity of osteoblasts, leading to new bone formation. But, the matter of concern here is that the new bone formed is weaker, larger, has an increased blood supply and is more prone to fracture. All these anomalies in bone remodeling marks the development of Paget’s disease.

This disease is named after a surgeon, Sir James Paget, who first described the condition as a chronic inflammation of bone and called it, Osteitis deformans (Osteitis means swelling of bone and Deformans means deformity). Paget’s disease is usually asymptomatic, i.e., it does not present with any symptom in majority of cases. However, sometimes patients may present with minor complaints, most common being the bone pain.

As per recent statistical reports, 1 to 3 million people in the U.S. are affected by this condition. It is the second most common disease of the bone after osteoporosis. Commonly seen in men than women, Paget’s disease is broadly considered as a disease of the elderly. Besides, it may affect young individuals, known as Juvenile form of Paget’s disease. It is very different from the adult form of Paget’s disease.

The exact cause of this disease is still a subject of interest for the researchers. However, a strong genetic predisposition has been considered a major cause of the condition. Paget’s disease can be a debilitating condition for the patient as it increases the risk of bone fracture due to the brittle nature of the bone. If not recognized and treated at an early stage, it may progress to bone cancer, which can eventually cause death. However, the progression of the disease to bone cancer is rare. Hence, it is necessary that the general population is aware of the disease and appropriate interventions must be taken at an early stage.

Types and Symptoms of Paget’s Disease of Bone

Types of Paget’s Disease of Bone:

Paget’s disease is a localized disease, which means, it is confined to a particular bone only, and does not spread. However, it may worsen the condition in the pre-existing site. It may affect a single bone or multiple bones at a time. Based on the number of bone(s) affected by Paget’s disease, it can be classified into 2 categories.

• Monostotic Paget’s disease: It refers to the involvement of only one bone. It accounts for 10 to 35% cases of Paget’s disease.
• Polystotic Paget’s disease: It refers to the involvement of 2 or more bones. This is a more common type of Paget’s disease.

Symptoms of Paget’s Disease of Bone:

The bones affected by Paget’s disease in decreasing order of frequency are spine, femur (thigh bone), pelvis, skull, clavicle (collarbone) and the humerus (upper arm bone).

In most cases, Paget’s disease does not present with any symptom and is usually diagnosed incidentally during medical evaluation for some other condition. However, it may present with some symptoms in minority of cases. The most common symptom is bone pain. The clinical presentation depends on the bone involved, as described below:

• Spine: If Paget’s disease involves the spine, it presents as pain in the back or neck, or tingling and numbness in leg or arm. The occurrence of for such symptoms is due to the fact that nerves lie around the bones. Paget’s disease is characterized by the formation of larger bones that compress the adjacent nerve roots and produce these symptoms.
• Pelvis: Involvement of pelvic bone manifests as hip pain.
• Skull: An enlargement of skull bone in Paget’s disease can lead to nerve impingement and can cause hearing loss, loss of vision and headache.
• Leg: As the Paget’s disease progresses, the bones become softer and can eventually lead to bone deformity, clinically known as ‘bowing of legs.’

Other symptoms seen in Paget’s disease are listed below:

• Fracture of the Involved Bone: The newly formed bone in Paget’s disease is weak and brittle, which increases the chances of fracture.
• Warmer Skin Over the Affected Area: Another significant observation in Paget’s disease is warm skin over the affected bone area. This is due to rich blood supply to the newly formed bone in the disease.
• Increased Bone Bleeding: As already mentioned, the bone formed in Paget’s disease is more vascular, i.e., it has a rich blood supply. Hence, whenever there is trauma to the bone, the bleeding from the affected bone is more in comparison to healthy bone.

If the Paget’s disease is not diagnosed and managed early, it may lead to severe complications. Some major complications of Paget’s disease are as follows:

• Arthritis: It is a degenerative condition affecting the joints. When there is bowing of legs, the adjoining joints may experience extreme stress due to abnormal mechanics and can lead to joint pain and inflammation. For instance, if Paget’s disease involves the femur bone (or, thigh bone), it exerts undue stress on the knee joint and causes degenerative wear of the joint. It manifests as joint pain.
• Heart Failure: This is another major complication that may occur in patients of Paget’s disease with extensive bone involvement (i.e., more than 40%). When there is abnormal bone formation, the heart has to work harder to pump blood to the affected area so as to maintain adequate circulation. This increases the work load on the heart that can lead to heart failure.
• Bone Cancer: Scientifically, it is termed as Osteosarcoma. It is a rare complication of Paget’s disease, and occurs in less than 1% of the affected individuals. It is marked by sudden, severe localized pain in the bone along with the presence of a soft tissue mass. Though rare, it is an extremely aggressive cancer and can be fatal.

Risk Factors of Paget’s Disease of Bone

There are various risk factors that may predispose an individual to Paget’s disease. These are as follows:

• Family History: Research has proved that Paget’s disease runs in families. Hence, a person is at a greater risk if any of his family members is suffering from the disease.
• Age: As already mentioned, Paget’s disease is a disease of the elderly. The chances of acquiring Paget’s disease are higher after the age of 40. However, as the disease is usually asymptomatic in the earlier stages, it is diagnosed when an individual is in his 50s. Paget’s disease is rarely seen in children and young adults.
• Gender: Paget’s disease is seen in both males and females, but men are comparatively more prone to develop this condition.
• Nationality: Paget’s disease also shows a geographical predilection. It is more commonly seen in Scotland, Greece, England and Central Europe. It is less commonly seen in Asia and Scandinavia. This trend could be explained by the genetic inheritance of the disease and population migration.

Do I have Paget’s Disease of Bone?

If an individual is a male in his 40s and has a family history of Paget’s disease, he is at the greatest risk of developing the disease too.

However, women, children and young adults may also be affected. A positive family history makes a person more susceptible to develop Paget’s disease regardless of his age, gender and nationality.

If an individual is experiencing dull bony pain or is developing a visible bone deformity in his/her skeleton, Paget’s disease may be the likely explanation. Bony pain along with visual impairment and hearing difficulties might be suggestive of Paget’s disease involving the skull.

However, if an individual had been experiencing dull bony pain, which has now worsened and can feel a soft tissue mass in the affected area, then it may may point toward bone cancer, which needs prompt treatment. Likewise, in case an individual has developed bone deformity, such as bowing of legs and is also experiencing pain in the respective joint, it is a strong indicator of Osteoarthritis occurring as a complication of Paget’s disease. Hence, it is always recommended to visit a doctor for proper diagnosis.

Causes and Prevention of Paget’s Disease of Bone

Causes of Paget’s Disease of Bone:

The exact cause of Paget’s disease is still a matter of active research. However, two main causative factors have been recognized in the development of Paget’s disease.

• Genetic Predisposition: Scientists have proved that Paget’s disease is transmitted through genes. Certain genes have been found to be implicated in the development of the disease. One of them is Sequestosome 1 gene located on Chromosome 5. This means that individuals with this particular gene in their genetic make-up are at a higher risk of developing the disease and transmitting it to the next generation.However, genetic factor alone may not always cause the disease. Research has shown that a combination of genetic and environmental factor is responsible for the onset of Paget’s disease.
• Environmental Factor (Viral Infection): The only recognized environmental factor till date which contributes to the development of Paget’s disease is viral infection. In relation to this, a theory has been postulated to explain the development of Paget’s disease. This theory is known as “Slow virus theory.” Before understanding the principles of this theory, it is important to know that osteoclasts originate in the bone marrow, which means that bone marrow cells mature to form osteoclasts.
  Slow virus theory suggests that entry of virus in an individual’s body can infect the bone marrow cells leading to an abnormal activity of osteoclasts which further disrupts the bone remodeling. This eventually causes Paget’s disease. The most significant virus that is known to evoke this response is Measles virus. The interesting fact is that this virus may remain dormant in the human body for long, and can cause Paget’s disease years after the entry.

Prevention of Paget’s disease of Bone:

The disturbing fact is that Paget’s disease cannot be prevented. If an individual is at a high risk of developing the disease, he/she will develop it. However, preventive measures can be taken to arrest the disease at its earliest stage. Major preventive measures that one must keep in mind to prevent the complications of the disease are described below.

• Know Your Family History: One must stay informed of his/her family history. If a positive family history is present, one must always get regular check-ups done to ensure that the disease is recognized and managed at an early stage.
• Seek Treatment at the Earliest: The initial asymptomatic stage of the disease makes it impossible for the patient to seek treatment. But, if an individual develops any symptom specific to the disease and has a strong family history, it is important to seek professional help immediately. Also, if a person has been diagnosed with the disease, it is important to get the treatment at the earliest. Early treatment ensures the avoidance of debilitating complications, such as arthritis, heart failure and in the worst-case scenario, bone cancer.

Diagnosis and Tests of Paget’s Disease of Bone

Paget’s disease is usually diagnosed when an individual is undergoing a medical evaluation. The reason being, its asymptomatic nature in the early stages. However, once a physician suspects Paget’s disease in a patient, several investigations are carried out that as listed below:

• Bone Scan: It is the best diagnostic test for Paget’s disease. This procedure involves the infusion of dye in the patient’s arm. This dye gets accumulated in the damaged area of the bone. Thereafter, a special camera is used to scan the bone. This helps in localizing the damaged section of the affected bone.
• X-Ray: Once the affected bone has been localized through bone scan, a bone X-ray is taken to assess the extent of the deformity. X-ray of a Paget’s disease patient shows large and deformed bone. Bowing of bone is clearly noticeable in an X-ray.
• Lab Tests: The most significant lab test in the diagnosis of Paget’s disease is serum Alkaline Phosphatase (SAP) test. Alkaline phosphatase enzyme is produced during bone remodeling. In Paget’s disease, there is elevated serum alkaline phosphatase, which signifies the abnormality in bone remodeling. SAP test is also done in between the treatment procedure to monitor the efficacy of the treatment. Other than SAP, certain urinary markers are also diagnostic of Paget’s disease.
• Advanced Diagnostic Modalities: MRI and CT may be needed to get a clearer view of the affected bone.
• Bone Biopsy: This test is not done in all the cases of Paget’s disease. It is indicated only if the doctor is suspecting bone cancer.

As this disease usually presents after 40 years of age, most patients ignore the bony pain thinking it a sign of normal aging. It is important for the individuals to realize that such symptoms along with a strong family history must seek medical help.

The features of Paget’s disease are sometimes confused with those of Osteoporosis. The difference between the two lies in their extent, i.e., Osteoporosis is a generalized condition, whereas Paget’s disease is a localized disease.

Treatment and Care of Paget’s Disease of Bone

Treatment of Paget’s Disease of Bone:

There is no cure for Paget’s disease. Hence, the goal of the treatment is to control the activity of the disease, relieve the symptoms and manage its complications. As already described, Paget’s disease affects many systems of the body, including bones, joints and even hearing ability. Thus, it’s treatment requires multi-disciplinary approach, i.e., a team of specialists collaborate to manage the condition effectively. Usually, an orthopedic surgeon (specialist of bone disorders), rheumatologist (specialist of musculoskeletal diseases and autoimmune disorders) and ENT specialist (specialist of Ear, Nose and Throat diseases) work together to manage the individual manifestations of the disease.

The treatment depends on the symptoms and the SAP levels. If a patient is asymptomatic with minimally elevated SAP, no treatment is required. However, if the disease is seen affecting major bones like skull or spine, treatment is necessary to prevent fatal complications. If a patient presents with symptoms and lab tests reveal marked elevation of SAP, treatment must be advocated. The various treatment modalities are as follows:

1. Medications:

Various drugs used in the treatment of Paget’s disease are discussed below:

A. Bisphosphonates: The mainstay of the treatment for Paget’s disease is the use of a drug, called Bisphosphonates. This class of drug suppresses the bone-destroying cells; hence, arresting the disease. These can be taken orally or through injections. The efficacy of bisphosphonate in the treatment is checked by the reduction in symptoms of the patient and reduction in SAP levels of the patient. The examples of bisphosphonates are enlisted below:

Oral drugs

• Alendronate
• Risedronate

Injectable Drugs

• Pamidronate
• Zoledronic acid

Although bisphosphonates are the most important drug in the treatment of Paget’s disease, it may produce some side effects in some patients such as degeneration of the jaw, musculoskeletal pain, flu-like symptoms, gastric irritation and reduced calcium level.

B. Salmon Calcitonin Therapy (Available as Miacalcin): In patients, who cannot tolerate bisphosphonate therapy, salmon calcitonin therapy is prescribed. Calcitonin is a hormone that inhibits the osteoclastic activity, and thus, reduces the bone destruction. It arrests the disease and prevents its progression. It is given either through injections or as a nasal spray. Injectable forms are given under skin or into the muscles. Nasal sprays are administered inside the nostrils.

However, calcitonin too causes some side effects in injectable as well as nasal spray form. vomiting, nausea, redness at the site of injection, skin rash and flushing are a few side effects of the calcitonin injection, while nose bleeding, runny nose (also, known as rhinorrhoea), headaches and bone pain.

C. Painkillers: Bone pain can be very disturbing for the patients of Paget’s disease. NSAIDs (non-steroidal anti-inflammatory drugs) or painkillers are prescribed by the doctor to relieve the pain.

2. Surgery

Surgical intervention for Paget’s disease is rarely needed. It is usually indicated in cases of unstable bone fracture and severe arthritis not responding to medications.

Because of the abnormal bone architecture and increased blood supply of the bone in Paget’s disease, the surgeon has to face many challenges during the procedure. The major challenge is increased tendency of bone bleeding during the surgery. To combat this, surgeons put the patients on medications a few months prior to the surgery. Medications reduce the severity of the condition to a considerable extent, which reduces the chance of bleeding during the surgery.

Various surgical procedures that may be required are as follows:

• Total Joint Replacement: It is done in case of severe degenerative arthritis. Usually, hip or knee joint replacement is required.
• Realignment of Deformed Bone: Bone deformity is a common presentation in this disease. Severely deformed bones may need surgical approach for their realignment.
• Nerve Decompression: As already stated, bone formed in Paget’s disease is large and can compress the surrounding nerves. In such cases, nerve decompression is done surgically to relieve the symptoms.

3. Rehabilitation

Daily activities can be cumbersome for a patient with Paget’s disease due to various reasons like bone fracture or extremely brittle bone susceptible to fracture, bone deformity affecting joint mobility and hearing loss. To curb these limitations, various rehabilitation measures are recommended by the doctor. These are described below:

• Physiotherapy: It strengthens the muscles and improves the balancing ability of the patients; thus, reducing the risk of falling. This in turn, prevents the brittle bones from fracture.
• Cane or Walker: Gait abnormality is a common finding in Paget’s disease due to bone deformity. These devices assist the patient in walking and reduces the chances of falling of the patient.
• Splints and Braces: These provide support to the weak bones of the patients and prevents their fracture.
• Hearing Aid: These are needed if the disease has involved the skull and caused hearing impairment.

Care for People with Paget’s disease of Bone:

Paget’s disease is usually diagnosed in the 50s of an individual. Sometimes, by the time it is diagnosed, it may have caused many debilitating complications. Arthritis, hearing loss and nerve compression can render a patient helpless and it may be difficult for him/her to lead daily life without assistance. Hence, it is important for the family members and peers to assist the patient and make the patient’s life easy.

Paget’s disease can affect the mental state of an individual by making him/her dependent on rehabilitating devices. Thus, the closed ones should motivate the patients to believe that the disease is manageable.

OTC and Self-Management Methods for Paget’s Disease of Bone

Over-the-Counter (OTC) Medications for Paget’s Disease of Bone:

While bisphosphonates and calcitonin require prescription, some OTC pain-killers like acetaminophen, ibuprofen or naproxen can be taken to relieve the pain caused by the disease.

Moreover, bisphosphonates and calcitonin cause a reduction in blood calcium level. Hence, doctor usually prescribes a calcium and vitamin D supplement along with these medications. These supplements are available over the counter. However, it must be noted that calcium reduces the absorption of bisphosphonates, and so, reduces its efficacy. Thus, patients are advised to maintain a gap of at least 2 hours between the intake of bisphosphonates and calcium supplements.

Self-Management Methods for Paget’s Disease of Bone:

Other than medical intervention, self-management plays a vital role in managing Paget’s disease. Various ways to self-manage the disease are as follows:

• Maintain a Pain Diary: This can help the patient know what aggravates the pain; thus, making it easier for the patient to manage pain.
• Avoid Falls: Weak brittle bones in Paget’s disease predisposes a patient to bone fractures. Hence, falling must be avoided. Other than rehabilitation devices recommended by the doctor, make your home fallproof. Make sure your walkways are clutter free. Get rid of slippery floor mats. Incorporate grab bars in bathrooms. Place non-skid mats in the shower area.
• Healthy Diet: Paget’s disease causes weak bones and unfortunately, the medications lowers the blood calcium levels. Hence, an adequate nutrition is indispensable to a better life quality in this disease. Make sure that the patient’s diet is rich in calcium and vitamin Incorporate foods like poppy seeds, yogurt, cheese and other calcium-rich items in your daily diet. Sunlight is a good source of Vitamin D. However, it is necessary to get the diet chart reviewed by the doctor.
• Exercise Regularly: Exercising can be an extremely tough task for patients of Paget’s disease. But, Paget’s disease patients are required to maintain a constant skeletal activity. Managing weight is important for these patients as excess weight can put undue stress on weight-bearing bones of the body, predisposing them to fractures. However, it must be done under a professional guidance as putting too much of stress on the bones can also lead to fractures.

Natural Ways to Cure Paget’s Disease of Bone

As already mentioned, Paget’s disease cannot be prevented. However, there are some natural ways to manage it:

• Get Enough Sunlight: Sunlight is a rich source of Vitamin D. So, getting enough sunlight strengthens the bones can benefit the patients of Paget’s disease.
• Eat Calcium-Rich Diet: Reduced blood calcium is a major concern in patients of Paget’s disease. Hence, it is necessary to incorporate enough calcium in the diet.
• Exercise Regularly: Exercising can help the patients manage weight, hence reduces the risk of bone fracture.

Health Tip by Expert

Health experts suggest that every individual must realize that Paget’s disease is an unavoidable bone disorder. However, recognizing it at an early stage can prevent its complications. Arresting the disease at an early stage can significantly improve the quality of life of an individual. Hence, be informed of your family history. If suspecting the disease, seek medical help immediately. Once diagnosed, strictly adhere to the drug regime. Follow a healthy diet and stay active.