Paget's disease is a chronic condition that affects bone growth. There is an increase in both the breakdown and formation of bone tissue, which leads to deformed bones. Alkaline phosphatase is often elevated in, but not exclusively to, this disease.
Causes
A cause for Paget's disease has, so far, not been identified but experts suspect that a viral infection of the bone may be a cause. Hereditary factors may contribute to this disease.
Symptoms
Paget's disease most commonly asymptomatic or symptom free. When symptoms occur, they include bone pain, abnormal bowing of bones in the legs, skull enlargement and fractures. Disease sometimes affects the bones of the spine, causing a narrowing of the spinal column, which can damage nerves and cause leg pain, weakness and numbness. It may also cause cauda equina syndrome or a condition involving the loss of sensation in the legs and pelvic area.
Complications
The increased activity in bone tissue leads to increased blood flow to the bones by dilation of blood vessels; this delivers more oxygen and nutrients to support the activity in bone. Dilation of blood vessels causes a drop in blood pressure, which forces the heart to compensate by pumping harder; over time, Paget's disease leads to heart failure. Osteoporosis may result from redistribution of weight caused my poorly aligned bones. The increased activity in bone also disrupts its framework and therefore its strength; this increases the likelihood for fractures.
Diagnosis
X-rays are used to confirm the diagnosis of Paget's disease. Other imaging studies such as CT scan and MRI may also be used as alternatives to x-ray. A bone biopsy is rarely needed to diagnosis the disease. Alkaline phosphatase increases in the blood in response to increased bone activity, which is the case in Paget's disease. Alkaline phosphatase can be elevated in other diseases, and therefore cannot be used alone to diagnose Paget's disease.
Treatment
Paget's disease is treated with bisphosphonates, a class of drugs that has proved effective at increasing bone density and reducing the likelihood for fractures. Calcitonin, a hormone produced naturally in the body by the thyroid gland, can be used to treat Paget's disease in some cases, but it's not nearly as effective as the bisphosphonates.
