Osteoporosis is a bone disease that develops when bone mineral density and bone mass decreases, or when the quality or structure of bone changes. This can lead to a decrease in bone strength that can increase the risk of fractures.
Osteoporosis affects women and men of all races and ethnic groups. Osteoporosis can occur at any age, although the risk for developing the disease increases as you get older. For many women, the disease begins to develop a year or two before menopause. After age 50, one in two women and one in four men will have an osteoporosis-related fracture in their lifetimes. Another 30% have low bone density that puts them at risk of developing osteoporosis. This condition is called osteopenia.
Osteoporosis is a “silent” disease because patients typically do not have symptoms and may not even know they have the disease until a fracture occurs. Osteoporosis is the major cause of fractures in postmenopausal women and in older men. Fractures can occur in any bone but happen most often in bones of the hip, vertebrae in the spine, and wrist. Symptoms of vertebral fracture include severe back pain, loss of height, or spine malformations such as a stooped or hunched posture (kyphosis).
About 200 million people are estimated to have osteoporosis throughout the world. It is responsible for more than two million fractures each year, and this number continues to grow.
Bone metastasis occurs when cancer cells spread (metastasize) from their original site to a bone. Nearly all types of cancer can metastasize to the bones. However, some types of cancer are more prone to bone metastasis such as breast, lung, prostate, kidney, skin, ovarian, and thyroid cancer. Bone metastasis can occur in any bone but more commonly occurs in the spine, hip bone (pelvis), upper leg bone (femur), upper arm bone (humerus), ribs, and the skull. Bone metastasis may be the first sign of cancer, or bone metastasis may occur years after cancer treatment.
Bone metastasis can cause pain and broken bones. When cancer cells spread to the bone, they block or speed up the the osteoblasts and osteoclasts' activities, breaking down or making too much bone. . Either of these changes can make bones more fragile than usual. Bone metastases can cause other problems such as spinal cord compression and high blood calcium levels (hypercalcemia). Spinal cord compression can cause nerve damage leading to paralysis if not treated immediately.
Rarely can bone metastasis be cured but treatments often help reduce pain and other symptoms. Common therapies include bisphosphonate (such as pamidronate and zoledronic acid) and monoclonal antibody (such as denosumab). Treatment with one of these drugs can help prevent further bone damage and events related to weakened bones, such as fractures, hypercalcemia, and spinal cord compression.
With advanced treatment, most fractures heal adequately. After receiving treatments, new bone tissue begin to form and connect with other bones. However, some bone fractures do not heal even with the best surgical or nonsurgical treatments. Certain risk factors sometimes make it less likely that a bone will heal. When a broken bone doesn't heal, it is called a "nonunion." When a broken bone takes longer than usual to heal, it is called a “delayed union”.
Nonunions occur when the bone lacks adequate stability, blood flow, or both. In addition, nonunions are more likely when the fracture is sustained from a high-impact injury such as a car accident because it often impairs the blood supply.
Patients with nonunions usually continue to experience residual pain at the fracture sites after the initial pain of the fracture disappears. The pain may be constant or evoked only by momvement at the fracture site, and may last for months or even years.
Muscle Disorders are diseases and disorders that affect the human muscle system, and primarily manifest as skeletal muscle weakness. Muscle disorders include dystrophy, neruomuscular conditions, and neuromuscular diseases. These disorders are a large group of conditions that affect the muscles, such as those in the arms and legs or heart and lungs, or the nerves which control the muscles. Muscle disorders may cause weakness or paralysis in the presence of an intact nervous system. There are multiple types of muscle disorders. The common types include myopathies (like Duchenne muscular dystrophy, spinal muscular atrophy), myasthenia gravis, and sarcopenia.
Causes of muscle disorders include age, genetic disorders, inflammation, metabolic disorders, and more.
Symptoms may include muscle weakness that slowly worsens, muscle wasting with loss strength, muscle stiffness, and mobility problems.