Paget’s disease, also called osteitis deformans, is a slowly progressive metabolic bone disease characterized by an initial phase of excessive bone resorption (osteoclastic phase), followed by a reactive phase of excessive abnormal bone formation (osteoblastic phase). The new bone structure, which is chaotic, fragile, and weak, causes painful deformities of both external contour and internal structure. Paget’s disease usually localizes in one or more areas of the skeleton (most frequently the lower torso), but occasionally skeletal deformity is widely distributed. It can be fatal, particularly when it’s associated with heart failure (widespread disease creates a continuous need for high cardiac output), bone sarcoma, or giant-cell tumors.
The disease occurs worldwide, but is more common in Europe, Australia, and New Zealand, where it’s seen in up to 5% of the elderly population. Although its exact cause is unknown, one theory holds that early viral infection causes a dormant skeletal infection that erupts many years later as Paget’s disease. Genetic factors are also suspected.
Clinical effects of Paget’s disease vary. Early stages may be asymptomatic, but when pain does develop, it’s usually severe and persistent and may coexist with impaired movement resulting from impingement of abnormal bone on the spinal cord or sensory nerve root. Such pain intensifies with weight bearing.
The patient with skull involvement shows characteristic cranial enlargement over frontal and occipital areas (hat size may increase) and may complain of headaches. Other deformities include kyphosis (spinal curvature due to compression fractures of pagetic vertebrae), accompanied by a barrel-shaped chest and asymmetrical bowing of the tibia and femur, which commonly reduces height. Pagetic sites are warm and tender and are susceptible to pathologic fractures after minor trauma. Pagetic fractures heal slowly and usually incompletely.
Bony impingement on the cranial nerves may cause blindness and hearing loss with tinnitus and vertigo. Other complications include hypertension, renal calculi, hypercalcemia, gout, heart failure, and a waddling gait (from softening of pelvic bones).
X-rays taken before overt symptoms develop show increased bone expansion and density. A bone scan, which is more sensitive than X-rays, clearly shows early pagetic lesions (radioisotope collects around areas of active disease). Computed tomography scan or magnetic resonance imaging shows extra bony extension if sarcomatous degeneration occurs. Bone biopsy reveals characteristic mosaic pattern.
Other laboratory findings include:
❑ elevated serum alkaline phosphatase levels (an index of osteoblastic activity and bone formation)
❑ elevated serum calcium.
Increasing use of routine chemistry screens (including serum alkaline phosphatase) is making early diagnosis more common. Serum osteocalcin and N-telopeptide are usually increased.
Primary treatment consists of drug therapy and includes one of the following:
❑ Calcitonin (subcutaneously or intranasally) is used to retard bone resorption (which relieves bone lesions) and reduce levels of serum alkaline phosphate and urinary hydroxyproline secretion. Although calcitonin therapy requires long-term maintenance, improvement is noticeable after the first few weeks of treatment.
❑ Bisphosphonates, such as etidronate, alendronate, pamidronate, tiludronate, and risedronate, produce rapid reduction in bone turnover and relieve pain. They also reduce serum alkaline phosphate and urinary hydroxyproline secretion. Therapy produces noticeable improvement after 1 to 3 months.
❑ Plicamycin, a cytotoxic antibiotic, is used to decrease calcium, urinary hydroxyproline, and serum alkaline phosphatase. It produces remission of symptoms within 2 weeks and biochemical improvement in 1 to 2 months. Plicamycin is used to control the disease and is reserved for severe cases with neurologic compromise and for those resistant to other therapies. However, it may destroy platelets or compromise renal function.
Orthopedic surgery is used to correct specific deformities in severe cases, reduce or prevent pathologic fractures, correct secondary deformities, or relieve neurologic impairment. Joint replacement is difficult because bonding material (methyl methacrylate) doesn’t set properly on pagetic bone.
Other treatment varies according to symptoms. Analgesics or nonsteroidal anti-inflammatory drugs may be given to control pain.
Patients with Paget’s disease require the following special considerations:
❑ To evaluate the effectiveness of analgesics, assess level of pain daily. Watch for new areas of pain or restricted movements, which may indicate new fracture sites, and sensory or motor disturbances, such as difficulty in hearing, seeing, or walking.
❑ Monitor serum calcium and alkaline phosphatase levels.
❑ If the patient is confined to prolonged bed rest, prevent pressure ulcers by providing good skin care. Reposition the patient frequently, and use a flotation mattress. Provide high-topped sneakers to prevent footdrop.
❑ Monitor intake and output. Encourage adequate fluid intake to minimize renal calculi formation.
❑ Demonstrate how to inject calcitonin properly and rotate injection sites or how to perform nasal inhalation if that’s the form prescribed. Warn the patient that adverse effects may occur (nausea, vomiting, local inflammatory reaction at injection site, facial flushing, itching of hands, and fever). Give reassurance that these adverse effects are usually mild and infrequent.
❑ To help the patient adjust to the changes in lifestyle imposed by this disease, teach him how to pace activities and, if necessary, how to use assistive devices. Encourage him to follow a recommended exercise program, avoiding both immobilization and excessive activity. Suggest a firm mattress or a bed board to minimize spinal deformities. Warn against imprudent use of analgesics because diminished sensitivity to pain resulting from analgesic use may make patient unaware of new fractures. To prevent falls at home, advise removal of throw rugs and other obstacles.
❑ Help the patient and his family make use of community support resources, such as a visiting nurse or home health agency. For more information, refer them to the Paget’s Disease Foundation.
Review other book chapters online related to Paget's disease of bone:
Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
|
More About This Book:
Title: Professional Guide to Diseases (Eighth Edition) Authors: Springhouse Publisher: Lippincott Williams & Wilkins Copyright: 2005 ISBN: 1-58255-370-X 
|
|
What do you think about the features of this website? Take our user survey and have your say:
Next articles:
Tools & Services:
Medical Articles:
Search Specialists by State and City
By using this site you agree to our Terms of Use. Information provided on this site is for informational purposes only; it is not intended as a substitute for advice from your own medical team. The information on this site is not to be used for diagnosing or treating any health concerns you may have - please contact your physician or health care professional for all your medical needs. Please see our Terms of Use.
Copyright © 2009 Health Grades Inc. All rights reserved.
