Medicines for Paget's disease of bone

What it is

Paget's disease of bone is a condition that disrupts the normal process by which bone is continually renewed (old bone being broken down and replaced by new bone). In Paget's disease, this renewal process becomes overactive and disorganised in one or more bones, so that the affected bone is broken down and rebuilt too quickly and in a disorganised way. As a result, the affected bones can become enlarged, misshapen, and weaker than normal, and more prone to problems. Paget's disease usually affects older adults, and becomes more common with age; the cause is not fully understood, though genetic factors and possibly other factors may play a role, and it can sometimes run in families. It can affect any bone, but commonly affects the pelvis, spine, skull, and the long bones of the legs; it may affect one bone or several. A very important point is that many people with Paget's disease have no symptoms at all — it is often discovered by chance, for example on an X-ray done for another reason, or on a blood test (which may show a raised level of a marker of bone activity). When Paget's disease does cause symptoms, these can include: bone pain in the affected area; the affected bone becoming enlarged or misshapen (for example bowing of a leg bone, or enlargement of the skull); joint pain or arthritis in a nearby joint; and, depending on the bone affected and the extent, other effects — such as, in some cases, effects from an enlarged bone pressing on nearby structures (for example, in the skull, affecting hearing), an increased tendency for the affected bone to fracture, or, rarely, other complications. Paget's disease is diagnosed with X-rays (which show the characteristic changes), blood tests, and sometimes bone scans. The good news is that Paget's disease is treatable where treatment is needed: many people without symptoms may simply be monitored, while those with symptoms or at risk of complications can be effectively treated, particularly with medicines (bisphosphonates) that control the overactive bone renewal and can relieve pain and reduce the disease activity, along with managing symptoms and any complications. The key messages are that Paget's disease of bone disrupts the normal renewal of bone, causing affected bones to become enlarged and weakened, that it often causes no symptoms, and that it is treatable where needed, particularly with medicines.

How it is treated

Paget's disease of bone is managed by monitoring those without symptoms, and treating those with symptoms or at risk of complications — particularly with medicines (bisphosphonates) that control the overactive bone renewal — along with managing symptoms and any complications. Diagnosis is made with X-rays (which show the characteristic changes in the affected bone), blood tests (which may show a raised level of a marker of bone activity, alkaline phosphatase), and sometimes bone scans (to show which bones are affected); it is often found incidentally. Once diagnosed, management depends on whether there are symptoms and the risk of complications. For many people who have no symptoms and where the disease is not affecting an area at risk of problems, the approach may be monitoring (keeping an eye on the disease, for example with blood tests), without active treatment, as treatment is not always needed for symptomless disease in certain locations. For people who have symptoms (such as bone pain), or where the Paget's disease affects certain bones or areas, or where there is a risk of complications, treatment is used and is effective: the main treatment is medicines called bisphosphonates, which work by controlling the overactive breakdown and rebuilding of the bone, thereby reducing the disease activity, relieving bone pain in many people, and helping to normalise the bone renewal; these are often given as a course (sometimes a single treatment can control the disease for a period), and the response is monitored (for example with the blood marker). Pain relief and other measures help manage bone or joint pain, and physiotherapy and aids can help with function. Managing complications is part of care where they occur — for example, managing arthritis in a nearby joint (which may sometimes need joint treatment or replacement), managing fractures, addressing effects such as those on hearing (if the skull is affected), and, rarely, other complications. Because the affected bone can be enlarged and weakened, care may be needed with the affected area, and any planned surgery on a Pagetic bone is managed with awareness of the condition. Ensuring adequate calcium and vitamin D (for bone health) is generally advised, particularly with bisphosphonate treatment. Ongoing monitoring and specialist input (such as from bone specialists) are used as needed. The reassuring messages are that Paget's disease of bone often causes no symptoms and may simply be monitored, that where treatment is needed it is effective — particularly with bisphosphonate medicines that control the disease and relieve pain — and that symptoms and any complications can be managed; so assessment, monitoring where appropriate, and effective treatment (particularly medicines) where needed are the keys to managing Paget's disease of bone.