- Paget disease is a disorder characterized by excessive resorption of bone and replacement of normal bone marrow with vascular, fibrous connective tissue and coarse, trabecular bone.
- The principle pathologic process is initiated by overactive osteoclastic bone resorption followed by a compensatory increase in osteoblastic new bone formation.
- There is increased vascularity of bone and increased blood flow through the cutaneous tissue overlying the involved bone, possibly secondary to local heat production by metabolically hyperactive affected bone.
- For an increased cardiac output to occur in Paget disease, there must be at
5% increase in involvement of the skeleton with an increase in alkaline phosphatase. - The increased cardiac output may precipitate heart failure if underlying heart disease is present.
- Augmentation of cardiac output obligated by the increased flow may not be manageable by the diseased heart, leading to heart failure.
- For example, if there is underlying severe aortic stenosis, the added demands placed on the heart by the need for increased flow through new vasculature may lead to clinical deterioration and heart failure.
- Paget disease is not uncommon, occurring in 3–4% of subjects >40.
- White individuals >55 are the group predominantly affected.
- Autosomal-dominant transmission has been described in certain cases.
- Heart failure due to Paget disease is unusual but could easily go unrecognized.
There is an increased incidence of Paget disease in 1st-degree relatives.
There are no known risk factors.
The etiology of Paget disease is unknown.
COMMONLY ASSOCIATED CONDITIONS 
- Metastatic calcification
- Headache
- Hearing loss