Paget’s disease of the bone is a rare condition affecting the elderly and it primarily involves a faulty bone metabolism.
Diagnosis of this condition is usually made in individuals over 40. It is rare in younger individuals.
Diagnosis of the condition may involve X-rays, blood tests and so forth.
X-rays to diagnose Paget’s disease
In some patients there may be no symptoms of the condition. Diagnosis in them is made by chance on X ray of the affected joint or on routine blood tests.
In early stages of the disease more bone is broken down and the bone may appear as riddled with black holes on X rays.
Later in the disease process these black areas can take the shape of a "V," with denser, thicker bone following behind it. This is known as 'the blade of grass' lesion.
The 'cotton wool' pattern in the skull is also characteristic where several woolly patches are seen over the skull on X ray.
On X rays the affected bone shows up as large, dense white and deformed. The shape may be bent or bowed seen in the long bones of the limbs. There may be evidence of a fracture in the bone as well.
Blood tests to diagnose Paget’s disease
Blood tests include those for serum alkaline phosphatase. This enzyme measures the bone turnover. It is usually quite elevated in patients with Paget's disease.
Usually blood levels of calcium, phosphorus, and parathyroid hormone are normal but prolonged immobility may lead to raised levels of blood calcium.
Urine tests to diagnose Paget’s disease
Urine tests also show signs of excess Calcium and rapid bone turnover. Urine levels of deoxypyridinoline and N-telopeptide are elevated.
Non-isomerised C-telopeptide fragments are also monitored to provide clues regarding disease activity and progression as well as treatment efficacy.
Bone scan to diagnose Paget’s disease
A bone scan or a PET (Positron Emission tomography) scan is advised for patients with Paget’s disease. In this test, a radioactive material is injected into a vein and it reaches all blood vessels of the body including those within the bones.
A special camera is used to look through the whole skeleton for areas or “hot spots” where the radioactive dye concentrates. These are areas of more bone turnover than usual.
Paget's disease almost always looks “hot” and active on a bone scan. As the disease progresses over a long time the spots area “burned out.”
Biopsy to diagnose Paget’s disease
Bone samples may sometimes be needed for biopsy. It is important to confirm the diagnosis of Paget’s disease. This test is advised before starting therapy to exclude other pathologies like:
- osteoporosis (bones becoming brittle with aging)
- metastatic or cancer of other organs (e.g. breast or lungs) spreading to the bones
Biopsy is also advised to exclude bone cancers. These biopsies are sometimes done with a needle to take a sample of the bone. The local area is numbed prior to insertion of the needle. Sometimes the biopsies may be performed using small incisions in the operating room.
Hearing tests to diagnose Paget’s disease
Hearing loss may be the first to be detected in Paget’s disease affecting the skull bones. Here various audiometry and hearing tests are performed to detect if hearing loss is due to nerve affliction or due to bone deformities. A CT scan or MRI of the skull may be advised.
Heart failure is detected in severe Paget’s disease.
Imaging studies to diagnose Paget’s disease
Due to high blood levels of Calcium from increased bone breakdown kidney stones may occur. These are detected by imaging studies like Ultrasound and X rays. (1-5)