Why are kidneys important for bone health?
Healthy kidneys do many important jobs. They remove wastes and extra fluid from your body, help make red blood cells, and help keep bones strong. They also help to keep the right amount of minerals in your blood. Minerals are nutrients that your body needs to stay healthy.
When you have kidney disease or kidney failure, your kidneys cannot do these important jobs well. As a result, you may develop mineral and bone disorder. It is a common problem in people with kidney disease, and it affects almost everyone with kidney failure.
What is mineral and bone disorder?
Mineral and bone disorder related to kidney disease happens when there is an imbalance in your blood levels of calcium and phosphorus. This mineral imbalance can affect your bones, heart and blood vessels.
How does kidney disease and kidney failure lead to bone and heart disease?
When too much kidney function is lost, your kidneys can no longer filter out extra phosphorus and remove it from the body in the urine. Over time, phosphorus from the foods you eat can build up to high levels in your blood.
Healthy kidneys also change vitamin D from sunlight and the foods you eat into active vitamin D that your body can use. When kidneys fail there is a short supply of active vitamin D. This causes calcium and phosphorus to get out of balance.
When the blood phosphorus level goes up and blood vitamin D level goes down, your body makes too much parathyroid hormone (PTH). High PTH levels cause calcium to move from your bones into your blood. As calcium leaves your bones they become weaker, more brittle, and are more likely to break. Some calcium may also end up in the heart and blood vessels. This may cause or worsen heart disease.
What are the signs and symptoms of mineral and bone disorder?
Mineral and bone disorder can cause you to have:
Weak bones that break easily
Blocked blood vessels
Difficulty fighting off germs
How do I know if I have mineral and bone disorder?
You will have blood tests to check your blood levels of calcium, phosphorus, PTH and vitamin D. Some people may need to have a bone biopsy. A bone biopsy is a sample of bone taken for study. Your healthcare provider may order an x-ray of your abdomen, or an echocardiogram of your heart to check if mineral imbalance has affected your heart and blood vessels.
How do you treat mineral and bone disorder?
Many people with kidney disease or kidney failure need treatment for high blood phosphorus or PTH levels. Your healthcare provider will order the treatment that is right for you.