Considerations in Diagnosis & Management of Paget’s Disease
Dr Clive Kelly is a Consultant Rheumatologist in Gateshead. Speaking at our Paget's Information Day in Middlesbrough, Dr Kelly discussed three case histories of patients with Paget’s disease. None were straight forward and so they show the difficulties that can be encountered when diagnosing and treating Paget’s disease. Dr Kelly has kindly provided summaries of the individual cases below.
Experienced clinicians often look upon Paget’s disease as an easy diagnosis to make and a condition that is readily treated. Although treatment of the condition can be much easier these days, there are however, still some pitfalls in both the diagnosis and management of the condition. These are illustrated by the three patient summaries below which highlight some of these issues.
A 76 year old gentleman had suffered with back pain for three months, associated with sleep disturbance and difficulty in micturition. Examination showed tenderness in the lower back on deep palpation, although the spinal architecture was normal. His blood tests showed an abnormal level of calcium, raised alkaline phosphatase (ALP) and a prostatic specific antigen (PSA) of 10 (normal 0-5). Plain x-rays of the lumbar spine demonstrated bony sclerosis in a vertebrae (L4) which was not present on his previous x-ray, taken five years before.
The trap here is to assume that the features represent Paget’s disease without exclusion of other possibilities. This patient may have prostatic cancer with bony metastasis as this may mimic Paget’s disease. The elevated PSA and micturition difficulty makes it important to refer him to a Urologist for further investigation. If a biopsy of the prostate or an MRI scan of the spine show evidence of cancer, then the treatment would be with hormonal manipulation therapy to treat the prostatic cancer. If however, investigations show monostotic Paget’s disease (Paget’s in just one bone), then therapy with a single infusion of 5 mg of intravenous Zoledronic acid may suffice to control his symptoms indefinitely.
An 83 year old lady presented with increasing pain in her right hip causing limited mobility. She could hardly climb the stairs in her house and the pain was disturbing her sleep. Examination showed features of generalised osteoarthritis in her fingers,while her right hip demonstrated marked reduction in rotation and pain on attempted flexion. Blood tests showed a slight rise in alkaline phosphatase, while a plain x-ray of her hip confirmed severe osteoarthritis with narrowing of the joint space and sclerosis. There was however, also widening of the trabeculae around the neck and head of femur with some expansion of the femoral head and variation in bone density at the same site.
The mistake here would be to assume that all her symptoms were due to osteoarthritis of the hip and to anticipate that a total hip replacement would solve her problems. In this situation, co-existing Paget’s disease is important to recognise and treat, as surgery may be likely to fail otherwise as a consequence of bony softening and / or fracture. A single infusion of Zoledronic acid may suffice to relieve symptoms and improve bone quality and density in the region of the hip, permitting elective surgery three to six months later if pain persists. The intravenous bisphosphonate alone, however, may lead to significant symptomatic improvement.
An 88 year old man presented to his GP with low back pain, radiating down the left leg. Examination showed a reduction in range of movement of the lumbar spine with little tenderness. Straight leg lift was reduced on the left and his ankle jerk and strength at the ankle were both reduced. Blood tests including alkaline phosphatase, calcium and PSA were all normal although a reduction in renal function was noted. A plain x-ray showed features of degenerative disc disease, most marked at the lumbosacral junction. There was also an area of abnormal bone in the right ilium, with sclerosis and coarsened trabeculae, strongly suggestive of Paget's disease, but no fracture was seen. These features were present on a previous x-ray 3 years earlier.
The patient appeared to have a disc prolapse at the lumbosacral junction with a resulting left radiculopathy causing symptoms. The radiographic features of his Paget's disease were unlikely to be associated with any symptoms, and the normal blood tests and stability of the radiographic changes made it most likely that his Paget's disease was neither active nor rapidly progressive. Treatment in this situation may actually carry more risk than benefit as there is no evidence that the treatment of asymptomatic lesions at this site alter outcome.
In summary, Pagets disease is common among the elderly and is easily treated in most cases with a single infusion of Zoledronic acid if renal function, calcium and vitamin d levels are adequate. Although further infusions can be given, in practice these are rarely needed at intervals of less than three years. Failure to correct vitamin D can precipitate hypocalcaemia and administration to patients with a glomerular filtration rate of less than 30 mls/minute, can also precipitate toxicity. Hence treatment of asymptomatic lesions in non-weight bearing bones may be avoided if the bone chemistry suggests low disease activity.