Three types of bone tissue--compact, cancellous and subchondral--make up the skeleton that shapes and supports the body. Compact tissue is the outer or hard part of the bone, cancellous is the sponge-like inner portion and the subchondral is the end of the bone covered in cartilage. Diseases affect all types of bone tissue, including the osteoblast, osteoclast and osteocyte cells within the bone.
Myeloma Bone Disease
Plasma cells are white blood cells in the bone marrow, or soft center, of most bones. Myeloma bone disease is a cancer that originates in the plasma cells when the plasma cell divides abnormally and becomes myeloma cells. As the myeloma cells reproduce and collect within the bone marrow, the solid part of the bone becomes damaged. Symptoms of myeloma bone disease include bone pain, weight loss, fatigue, weakness, back pain and frequent infections. Since the symptoms are similar to many other disease processes, diagnostic testing such as X-ray, bone marrow biopsy and magnetic resonance imaging, or MRI, provide information for a definitive diagnosis. University of Maryland Medicine reports that about 13,000 new myeloma bone disease cases are diagnosed every year.
Brittle Bone Disease
Brittle bone disease, also known as osteogenesis imperfecta, is a genetic defect in bone collagen type 1, the protein in the connective tissue. According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases, brittle bone disease occurs in about one out of every 20,000 people in the United States. The different types of the disease include Type I, II, III and IV. Types V and VI are additional types of brittle bone disease that are not related to the collagen type 1 defect. Symptoms include skeletal malformation, muscle weakness, triangular face, cardiac complications and short stature. Treatment focuses on minimizing fractures and strengthening muscles.
Paget's Disease of Bone
Paget's disease of bone, a chronic skeletal disease, affects about 3 to 4 percent of adults older than 50, according to the American Academy of Orthopaedic Surgeons. The normal bone process results in the continual absorption and reformation of bone. In Paget's disease, the absorption process is more active than the reformation. This imbalance causes the reformation process to overreact and create abnormally large and deformed bone that breaks easily. Symptoms range from none in very mild cases of Paget's disease to bone pain, fractures and obvious bone deformity. In rare cases, or about 1 percent of people with Paget's disease, Paget's sarcoma, an aggressive bone tumor with a poor outlook for survival, develops. Treatment options include observation with periodic X-rays, anti-inflammatory medications and braces. Surgery may be required for fractures, improper alignment and nerve compression.
