Paget's disease of bone explained

What Paget's disease of bone is

Healthy bone is living tissue that is constantly renewed: old bone is removed and fresh bone is laid down in its place, keeping the skeleton strong. In Paget's disease of bone, this renewal process becomes overactive and disorganised in one or more areas. Bone is broken down too quickly and then rebuilt too fast and untidily, so the new bone is larger but weaker and more fragile than normal, and can become bent or misshapen. It can affect a single bone or several, most often the pelvis, spine, skull, thigh bone or shin bone, but usually does not spread to unaffected bones. The exact cause is not fully understood, but it becomes more common with age and can run in families. It is not a cancer, and in many people it causes no trouble at all.

The symptoms it causes

Many people with Paget's disease of bone have no symptoms, and it is often found by chance on an X-ray or blood test done for another reason. When symptoms do occur, the most common is a deep, aching bone pain in the affected area, which may be there much of the time. The overgrown bone can change shape, for example causing bowing of a leg, an enlarged skull, or a curved spine, and joints near affected bones may become stiff or develop arthritis. If bones in the skull are involved, this can occasionally affect hearing. Because the abnormal bone is weaker, it is more prone to fractures. Symptoms depend very much on which bones are affected and how extensively, so the condition ranges from completely silent to a source of ongoing pain and deformity.

How it is diagnosed

Paget's disease of bone is often picked up by chance, for instance when an X-ray taken for another reason shows the typical thickened, altered bone, or when a routine blood test shows a raised level of a substance linked to bone activity. Where the condition is suspected, X-rays of the affected bones usually show its characteristic appearance and confirm the diagnosis. A blood test measuring bone activity can support the diagnosis and is useful for monitoring, and a special bone scan can show which bones are involved across the whole skeleton. Occasionally further imaging is done to look at a specific area or to check a complication. Reaching a clear diagnosis helps decide whether treatment is needed and allows any complications, such as affected joints or hearing, to be looked for and managed.

How it is managed

Not everyone with Paget's disease of bone needs treatment; those with no symptoms and no risk to important areas may simply be monitored. When treatment is needed, usually for bone pain or to protect a vulnerable bone, the main medicines are ones that slow down the overactive bone renewal, helping to reduce pain and control the disease, and these are prescribed and monitored by doctors. Pain can also be helped by ordinary pain-relief measures, and staying active and keeping a healthy weight supports bone and joint health. Physiotherapy, walking aids or supportive footwear can help where bones or joints are affected, and occasionally surgery is considered, for example to repair a fracture, replace a worn joint or straighten a badly bowed bone. Regular review helps monitor the condition and pick up any complications early.

Living with Paget's disease of bone

For most people, Paget's disease of bone can be well managed and does not shorten life. If you have no symptoms, you may simply have occasional check-ups, while those with bone pain or affected joints benefit from ongoing care to control symptoms and stay active. Keeping active within comfortable limits, maintaining a healthy weight, and looking after general bone health — including getting enough calcium and vitamin D as advised — all help. It is worth reporting new or worsening bone pain, changes in the shape of a bone, hearing changes if the skull is affected, or any new symptoms, so they can be assessed. Because the condition can occasionally run in families, close relatives are sometimes advised on when to seek checks. With monitoring and treatment when needed, many people live full and active lives with the condition.