The majority of patients with Paget's disease are asymptomatic. In patients who have symptoms, the most common is pain, which is usually localised to the area of pagetic bone disease. Occasionally, bone pain is due not to Paget's disease but rather to associated degenerative joint disease.
Patients develop characteristic deformities, most frequently an enlargement of the skull or outward bowing of the lower extremities. Furthermore, the disordered bone architecture may occasionally be associated with complications such as pathologic fracture, nerve entrapment syndromes due to increased bone formation, deafness (which may be due to compression of the eighth cranial nerve or to otosclerosis), cardiac failure due to increased cardiac output and increased blood flow through the highly vascularised Pagetic bones and, rarely, sarcomatous transformation.
