Paget disease of the bone is a skeletal ailment in which sections of bone experience abnormal turnover, resulting in enlarged and softer bone. The rate of bone breakdown and creation increases, resulting in larger but weaker bones than normal. Bone discomfort, bone deformities, arthritis, and painful nerve compression are all possible symptoms. The irregularities in the bones are seen on X-rays. Bisphosphonates may be used to manage pain and problems.
Paget disease can affect any bone, although the pelvis, thigh bone (femur), and cranium are the most usually afflicted. The tibia (shinbone), vertebrae (backbone), collarbone (clavicle), and upper arm bone (humerus) are less usually affected.
Paget disease is uncommon in people under the age of 40. The disease affects roughly 1% of adults over the age of 40 in the United States, and the prevalence rises with age. The disease’s prevalence, on the other hand, appears to be declining. It is 50 percent more prevalent in men than in women. In Europe (except Scandinavia), Australia, and New Zealand, Paget disease is more common.
Causes of Paget Disease of Bone
To preserve bone structure and integrity, cells that break down old bone (osteoclasts) and cells that make new bone (osteoblasts) normally function in harmony. Both osteoclasts and osteoblasts become overactive in some areas of bone in Paget disease, speeding up the rate at which bone is broken down and regenerated (a process known as bone remodeling). The hyperactive areas increase, yet they are structurally aberrant and feeble despite their size.
Osteoarthritis is the most common consequence of Paget disease of the bones (a joint disorder).
Osteoarthritis affects up to 50% of persons and might affect joints close to the affected bone.
Because the bones affected by Paget disease are weaker, they are more prone to fractures than normal. Pathologic fractures are the name for certain types of fractures.
Nerves and other structures passing through small apertures may be compressed by overgrown bone. The spinal canal may grow narrow, causing the spinal cord to be compressed.
Heart failure occurs seldom as a result of increased blood flow through the afflicted bone, which places additional strain on the heart. Because the blood flow through the damaged bones is unusually high, the surgery may result in significant bleeding. In less than 1% of persons with Paget disease, the damaged bone turns malignant. Osteosarcoma is a type of bone cancer that develops when a condition progresses to bone cancer (a cancerous bone tumor).
Hypercalcemia (excess calcium in the blood) is a rare complication of Paget disease in bedridden patients.
Paget Disease of the Bone Symptoms
Paget disease is frequently asymptomatic. Bone pain, expansion, or deformity are possible side effects. Bone pain can be deep, painful, and intense at times, and it can get worse at night. The growing bones may compress nerves, increasing pain. Joints become painful and stiff as a result of osteoarthritis.
The severity of the other symptoms varies depending on which bones are impacted.
The brow and forehead may appear more prominent, and the skull may grow (called frontal bossing). When a larger hat is required, this enlargement may be noticed. The inner ear (cochlea) can be damaged by enlarged skull bones, resulting in hearing loss and dizziness. Headaches are caused by the compression of nerves by the larger skull bones. The increased blood flow through the skull bones may cause the veins on the head to protrude.
Because Paget illness weakens the bone, it may seem bent and be more likely to shatter in the upper arm, thigh, or calf. Because the bones affected by Paget disease are fragile, they may grow, collapse, or both. Weakening vertebrae can cause a loss of height, a hunched posture, or squeezing of the spinal cord’s nerves, resulting in discomfort, numbness, and weakness.
Paget Disease of the Bone Diagnosis
- Blood tests
- Bone scan
When x-rays or laboratory tests are ordered for other reasons, Paget disease is frequently identified by accident. Other than that, Paget’s illness can be suspected based on symptoms and a physical examination.
X-rays showing anomalies indicative of Paget disease and a laboratory test to assess blood levels of alkaline phosphatase (an enzyme involved in bone production), calcium, and phosphate can confirm the diagnosis of Paget disease of bone.
Paget Disease of the Bone Prognosis
Paget disease patients typically have a fairly good prognosis. The few persons who get bone cancer, on the other hand, have a terrible prognosis. People who experience other unusual consequences, such as heart failure or spinal cord compression, may have a bad prognosis unless these complications are treated promptly and successfully.
Treatment of Paget Disease of Bone
- Treatment of pain and complications
If the symptoms are bothersome or if there is a significant danger or possibility of consequences, such as hearing loss, osteoarthritis, or deformity, a person with Paget disease should seek therapy. If you don’t have any symptoms, you might not need any treatment.
Analgesics such as acetaminophen and nonsteroidal anti-inflammatory medications (NSAIDs) are commonly used to treat bone pain. Heel lifts can assist make walking easier if one leg has become bent and shortened. Surgery may be required to alleviate pinched nerves or to replace an arthritic joint caused by Paget disease.
Bisphosphonates are a class of medications that slow down bone turnover. Alendronate, etidronate, pamidronate, risedronate, tiludronate, or zoledronic acid are some of the bisphosphonates that can be used to decrease the course of Paget disease. The bisphosphonate of choice is usually zoledronic acid. Except for pamidronate and zoledronic acid, which are administered intravenously, these medications are administered by mouth. These medications are used to treat the following conditions:
- Prior to undergoing orthopedic surgery During surgery, to prevent or minimize bleeding.
- To treat Paget disease-related bone discomfort.
- Complications (such as hearing loss, bone deformities, arthritis, weakness, or paralysis) are prevented or slowed in those who are unable to have surgery.
- People who have an alkaline phosphatase level in their blood that is twice the usual level or higher.
Calcitonin is injected under the skin or into the muscle on occasion. It is not as effective as bisphosphonates and is only used when the other options are unavailable. For those who are unable to take bisphosphonates, denosumab may be an option.
Weight bearing is recommended by doctors (such as standing and walking). To avoid hypercalcemia, excessive bed rest (save for sleeping at night) should be avoided if at all possible.
People should obtain enough levels of calcium and vitamin D in their diet since bone is rapidly rebuilt. Vitamin D aids calcium absorption and bone formation (a process called bone mineralization). Supplements of vitamin D and calcium are frequently required. Poor bone mineralization and bone weakening (osteomalacia) may result if this is not done.