What is Paget’s disease?

Paget’s disease is a bone disease that mainly affects the elderly and can cause pain, fractures, deformities, and nerve entrapments. Know its symptoms and treatment.

Paget’s disease is a chronic disease that affects bone. It is characterized by altered bone remodeling, which is excessive and disorderly, resulting in changes in the density, size, and consistency of the affected bones. The bones most commonly affected are the pelvis, spine, skull, femur, and tibia. Although it does not produce symptoms in many cases, it can cause pain and complications such as fractures, deformities, and nerve entrapments.

Under normal conditions, the cells that destroy the old bone (osteoclasts) and those that make up the new bone (osteoblasts) work in balance to maintain the structure and strength of the bone. In Paget’s disease, osteoclasts and osteoblasts become overactive in some areas of the bone, significantly increasing the rate at which bone turnover occurs. Overactive areas grow more considerably than usual and are enlarged. However, their structure is abnormal, and therefore they are more fragile than normal areas.

Sir James Paget, an English surgeon, first described the disease in 1876. It is also called osteitis deformans because of the inflammation of the bone and the secondary deformation it causes. After osteoporosis and osteoarthritis, it is one of the most common bone disorders in Western countries. Its incidence increases with aging, and it is very rare for it to manifest itself before the age of 40.

In general, Paget’s disease is a benign pathology since, in most patients, it hardly produces symptoms, or these are limited to bone pain and joint pain, which can be controlled acceptably with medication. As the disease progresses, it can produce some complications. One of them stands out for its importance and severity: patients with Paget’s disease have a higher risk of developing a malignant bone tumor called osteosarcoma. Fortunately, this complication is unusual, affecting only 1% of patients. It is necessary to suspect when the pain worsens or becomes persistent and cannot be controlled with drugs, in which case it is recommended to be reassessed by a doctor.

Causes and epidemiology of Paget’s disease

The cause s of Paget’s disease is not known. Some theories defend that a virus may produce it since viral inclusions (paramyxovirus such as measles, RSV, or dog distemper virus) have been found inside the bone cells (osteoclasts) of affected people. The most widely accepted theory currently suggests that Paget’s disease is caused by the sum of environmental factors and genetic factors.

Paget’s disease mainly affects people over 60 years of age and is rare before 40. The prevalence of the disease over 55 years of age is approximately 2.5% in men and 1.6% in women, figures that increase to 6.9% and 5.8%, respectively if analyzes by the population group aged 85 and over. It is somewhat more common in men than in women, and there is usually a family history of the disease in up to 40% of cases.

From a geographical point of view, it is more frequent in Western Europe (especially in England), the United States, Australia, and New Zealand. It affects almost approximately 1.5% -3% of the population over 65. In other areas such as Scandinavia, Central or South America, Japan, China, India, or Africa, Paget’s disease is rarer. 

Symptoms of Paget’s disease

Most patients with Paget’s disease remain without symptoms for a long time, so up to 40-60% of cases. The disease’s diagnosis is an accidental finding that occurs when analyzing an X-ray or a blood test. Blood was requested during the study for another disease.

The most common symptoms or signs of Paget’s disease are:

  • Bone pain: it is the most frequent symptom. It is a constant, burning pain that is unrelated to movement.
  • Joint pain: the joints most affected are the hip, shoulder, and knee. Osteoarthritis usually appears over time, which can cause mobility disturbances.
  • Spinal cord involvement: in patients with Paget’s disease, it is not uncommon for there to be kyphosis (excessive increase in the normal curvature of the spine), vertebral crushing (the vertebrae “collide” with each other when the cartilaginous disc found between them and which acts as a pad, thus producing back pain) or significant stiffness of the spine.
  • Bone deformities: produced by the weight that the body exerts on the lower extremities. The most frequent are the tibia in saber and the femur in crook.
  • Increase in the skull’s size (which is known in medical terms as the pagetic skull).
  • Headache.
  • Local temperature rise: in superficial bones, such as the tibia or the skull, an increase in skin temperature can be seen due to an increase in the network of blood vessels at that level.