Most people with Paget’s disease of bone have no symptoms at all. An estimated 70 to 90 percent of cases are asymptomatic, often discovered by accident when blood tests or X-rays are done for other reasons. For the minority who do develop symptoms, bone pain is the most common complaint, and the specific signs depend heavily on which bones are affected.
Bone Pain and How It Feels
The hallmark symptom is a dull, aching pain that feels deep within the affected bone, below the surface tissues. Unlike the sharp, sudden pain of an injury, pagetic bone pain is constant and boring. It tends to get worse at night and with rest, which is one way it differs from osteoarthritis pain, which typically flares with activity and eases when you stop moving. The affected area may also feel warm to the touch because of increased blood flow to the overactive bone.
Weight-bearing makes things worse when the disease affects the legs or pelvis. Hip pain is especially common when the pelvis or upper thighbone is involved. Knee and shoulder pain can develop too, not because those joints are directly diseased, but because misshapen bones nearby change the mechanical forces acting on the joint.
Where Paget’s Disease Appears Most
Paget’s disease can affect any bone, but it shows up most often in the spine, pelvis, long bones of the legs, and skull. It rarely affects the entire skeleton. Most people have it in just one or two bones, which is why symptoms tend to be localized rather than widespread.
The location matters because it determines which symptoms you notice. Paget’s in a leg bone might cause a visible bow or a limp. Paget’s in the spine might cause back stiffness or nerve compression. Paget’s in the skull can lead to headaches or hearing changes. Each location brings its own set of problems.
Visible Changes to Bone Shape
Paget’s disease causes bones to break down and rebuild abnormally. The new bone is larger and denser than normal, but structurally weaker and more brittle. Over time, this can produce visible deformities. The most recognizable is bowing of the legs, where the shinbone or thighbone curves outward under the stress of supporting your body weight. The skull can also enlarge gradually, sometimes enough that hats no longer fit.
These changes happen slowly, over months or years. You might not notice bowing until a leg measurement confirms one side is different, or until pants fit oddly. Spinal involvement can lead to a stooped posture or loss of height as vertebrae become misshapen.
Hearing Loss and Headaches
When Paget’s disease affects the skull, overgrowth of bone can compress the delicate structures involved in hearing. This can cause hearing loss that may affect only one side. It tends to develop gradually and is sometimes the first symptom that brings someone to a doctor. Persistent headaches are another skull-related symptom, caused by the pressure of thickened bone.
Nerve Compression Symptoms
Enlarged, misshapen bones can press on nerves where they pass through or alongside bone. This is most common in the spine and skull. In the spine, overgrown vertebrae can narrow the spinal canal, a condition called spinal stenosis. The result is pain, numbness, tingling, or weakness in the legs, buttocks, or feet. You might feel pins and needles, or notice that your legs feel heavy or clumsy after walking a certain distance.
When the skull is involved, different cranial nerves can be affected. Beyond hearing loss, this can occasionally cause facial numbness or vision changes, though these are less common.
Joint Problems From Altered Mechanics
Paget’s disease frequently leads to secondary osteoarthritis. When bones near a joint become deformed, the joint surfaces no longer line up properly. The cartilage wears unevenly, and over time the joint becomes stiff and painful. The hips and knees are most commonly affected because they bear the most weight and are closest to the bones Paget’s disease favors.
This joint pain can be difficult to separate from the bone pain of Paget’s itself. A useful clue: joint pain from osteoarthritis tends to worsen with movement and improve with rest, while pagetic bone pain persists or worsens at rest and at night. Many people with Paget’s experience both types simultaneously.
Fractures in Weakened Bone
Despite being denser than normal, pagetic bone is structurally weaker and more brittle. This makes it prone to fractures, sometimes from surprisingly minor stress. Pathological fractures occur most commonly in the weight-bearing bones of the lower body: the femoral neck (where the thighbone meets the hip), the upper thighbone, and the shinbone. In fact, Paget’s disease often goes undiagnosed until someone sustains a fracture and imaging reveals the underlying bone abnormality.
Stress fractures can also develop gradually in bowed bones. These cause increasing pain with activity before a full break occurs. If you have known Paget’s disease and notice a sudden worsening of pain in a long bone, a new fracture is one of the first things to rule out.
Rare but Serious Complications
In advanced cases where Paget’s disease affects a large portion of the skeleton, the increased blood flow to overactive bone can strain the heart. The heart has to work harder to pump blood through the expanded network of blood vessels in affected bones. In rare cases, this can contribute to heart failure, with symptoms like shortness of breath, swelling in the legs, and fatigue.
The most feared complication is malignant transformation, where pagetic bone develops into bone cancer (osteosarcoma). This is rare, affecting less than 1 percent of patients, but it should be considered if there is a sudden, significant increase in pain or swelling in a bone previously affected by Paget’s disease. A rapidly growing mass or a dramatic change in the character of your pain warrants prompt evaluation.
Why Symptoms Often Go Unnoticed
Paget’s disease progresses slowly, and many of its symptoms overlap with conditions that are common in the same age group. Bone pain gets attributed to arthritis. Hearing loss gets chalked up to aging. A slight bow in the legs might not seem worth mentioning. The disease is most common in people over 50, which is the same population dealing with general wear and tear on joints and bones.
The combination of a high asymptomatic rate and easily overlooked symptoms means Paget’s disease is frequently caught incidentally. A routine blood test might show an unexpectedly high level of alkaline phosphatase, an enzyme that rises when bone turnover is abnormally active. Or an X-ray taken for an unrelated injury might reveal the characteristic thickened, disorganized bone pattern. If you have persistent, deep bone pain that worsens at night, unexplained hearing loss on one side, or a visible change in bone shape, these are the signs most worth investigating.