Paget Disease

By admin Last updated Feb 17, 2024

Ovid: 5-Minute Orthopaedic Consult

Editors: Frassica, Frank J.; Sponseller, Paul D.; Wilckens, John H.

Title: 5-Minute Orthopaedic Consult, 2nd Edition

> Table of Contents > Paget Disease

Paget Disease

Frank J. Frassica MD

Basics

Description

First described by Sir James Paget in 1877 (1), Paget disease (osteitis deformans) is a bone disorder commonly seen in the geriatric population.
As implied by the name “osteitis
deformans”, the involved bone may be severely deformed and enlarged,
features that suggest an inflammatory origin.
A chronic and slowly progressive disease of disorganized bone remodeling
Can affect any bone
Often asymmetric process
May involve one bone (monostotic) or multiple bones (polyostotic)
Classification:
- Active phase:
  - Early (lytic) phase: Purely bone destruction
  - Mixed phase: Both bone destruction and formation
  - Late (sclerotic) phase: Predominantly bone formation
- Inactive phase (patients 60–90 years old):
  - Many patients have inactive disease with no radiographic progression, symptoms, or laboratory abnormalities.

Epidemiology

This disease of late adulthood is rarely seen before the 4th decade of life.

Incidence

It affects 3–4% of the population >50 years old and is slightly more common in males (2).
It is more common in Caucasians of Anglo-Saxon descent (2).

Prevalence

Its prevalence increases with advancing age, up to 5–15% by the 9th decade (2).

Risk Factors

1st-degree relatives of affected persons
Advancing age

Genetics

Ample evidence exists to suggest that 1st-degree
relatives of affected persons carry a higher risk (up to 7 times
higher) of developing the disease than those without family history of
the disease.

Etiology

Genetic associations have been identified.
Infectious (one of the paramyxoviruses):
Some investigators believe that the cause is a slow virus because of
the long incubation periods, absence of fevers, and involvement of a
single organ system.

Diagnosis

Signs and Symptoms

Clinical manifestations depend on the severity of the disease and the site of involvement.
- Pain:
  - Many patients are asymptomatic, but others have mild to severe bone pain.
  - Acute bone pain suggests pathologic fracture or malignant degeneration.
  - Usually constant and unrelated to activity
- Frontal bossing and conductive hearing loss may be present.
- If the spine is involved, the patient may develop spinal stenosis with or without radiculopathy.
- Arthritis:
  - Pagetic arthritis is common in the hip and knee.
  - Patients have severe pain and difficulty in ambulating.

Physical Exam

The most common findings are bowing of the extremity and local warmth if the bone is subcutaneous, such as the tibia.
Restricted ROM is common in the hip in patients with pagetic arthritis.

Tests

The basic components of the diagnostic evaluation are:
- History and physical examination:
  - The involved area is warm to the touch because of the increased vascularity of the underlying bone.
- Laboratory tests
- Plain radiographs
- Bone scan to evaluate the extent of skeletal involvement

Lab

Increased serum alkaline phosphatase levels are noted.
The 24-hour urine may show an increase in
collagen breakdown products (N-telopeptide or hydroxyl proline,
pyridinoline cross links; normal in 5% of patients [2]).
Serum calcium usually is normal unless
concurrent generalized inactivity, hyperparathyroidism,
hyperthyroidism, or malignancy is present.

Imaging

Radiography:
- Plain films show enlarged bone with thick, coarsened trabeculae and sclerotic and lytic changes in the affected bone.
- A flamed-shaped area of radiolucency strongly suggests an advancing edge of a pagetic lesion.
A “hot” technetium-99m methylene diphosphonate bone scan also is observed.
The bone scan will quantify the number of bones involved.

Pathological Findings

Highly vascular bone resulting from high turnover rate
Multiple pathologic fractures resulting from structurally weaker bone
Histologically, more numerous osteoclasts and less mature (but fully mineralized) bone

Differential Diagnosis

Metastatic cancer
Fibrous dysplasia
Paget sarcoma

Treatment

General Measures

Therapy depends on the severity of the disease: Not all patients require treatment.
Indications for treatment include bone pain, high-output cardiac failure, and prevention of pathologic fracture.
Pain from associated arthritis can be treated with NSAIDs.
A cane or walker may be used for gait stabilization.
Surgery is indicated for patients with
severe arthritis who are refractory to medical management or for
patients with impending pathologic fractures.
- Preoperatively, medical therapy should be
  initiated to reduce disease activity, to minimize blood loss, and to
  optimize surgical outcome.

Special Therapy

Physical Therapy

Physical therapy may be used to improve the patient’s ambulatory ability before or after surgery.

Medication

Medical treatment should be initiated for
symptomatic patients or in preparation for orthopaedic surgery to
prevent perioperative hypercalcemia or excessive bleeding.
- Calcitonin:
  - Inhibits bone resorption by direct action on osteoclasts
  - Side effects include nausea, facial flushing, and polyuria.
Diphosphonates (commonly used):
- Potent inhibitors of bone resorption
- Bind to hydroxyapatite crystals in bone and thereby prevent osteolysis
- Also may function as metabolic poisons for osteoclasts
- Common side effects include nausea, vomiting, and loose bowel movements.

Surgery

Surgery usually is undertaken for 1 of 3 reasons:
- Replacement of an arthritic joint
- Internal fixation of a long-bone fracture
- Correction of a long-bone deformity
Total hip and knee arthroplasty is extremely effective in relieving pain and improving function.
Intramedullary nails are the main modality for fixing long-bone diaphyseal fractures.
- Multiple osteotomies may be necessary to correct the deformities.

P.305

Follow-up

Prognosis

Most patients with Paget disease are asymptomatic and have a normal life expectancy.
Long-term survival for patients with Paget sarcoma (<1% of patients with Paget disease) is poor: ~20% survival in 5 years (3).

Complications

Pathologic fractures
High-output cardiac failure
Malignant degeneration (Paget sarcoma)

Patient Monitoring

Patients usually are followed once a year.
Usually, plain radiographs are obtained.

References

1. Paget J. On a form of chronic inflammation of bones (osteitis deformans). Med Chir Trans 1877;60:37–63.

2. Siris
ES, Roodman GD. Paget’s disease of bone. In: Favus MJ, ed. Primer on
the Metabolic Bone Diseases and Disorders of Mineral Metabolism, 6th
ed. Washington, D.C.: American Society for Bone and Mineral Research,
2006:320–330.

3. McCarthy
EF, Frassica FJ. Paget’s disease. In: Pathology of Bone and Joint
Disorders: With Clinical and Radiographic Correlation. Philadelphia: WB
Saunders, 1998:165–173.

Miscellaneous

Codes

ICD9-CM

731.0 Paget disease of bone

Patient Teaching

Patients should be well informed about their disease and the goals of treatment.
Treatment should be aimed at slowing or arresting disease progression, providing pain relief, or restoring function.
Appropriate consultations should be made to address any extraskeletal abnormalities (e.g., deafness).
The need for long-term follow-up should be emphasized.
Resources for patient education in the
United States can be obtained from the Paget Foundation, 200 Varick
Street, New York, NY 10014 (Telephone: 212-229-1502).

FAQ

Q: Are there effective treatments for Paget disease?

A: Diphosphonate therapy is very effective in halting bone resorption in Paget disease.

Q: Is hip replacement successful in patients with Pagetic arthritis of the hip?

A:
Joint replacement surgery is an excellent method of relieving pain and
improving function in patients with Paget disease of the hip.

Q: What are the warning signs of cancer in Paget disease?

A:
Bone pain or the development of a soft-tissue mass are the earliest
signs. Cortical bone destruction and a soft-tissue mass can be detected
with CT or MRI.