Pathophys of Pagets Disease of the Bone

​Pathophys of Pagets Disease of the Bone

By Micah Char

• Describe the pathophysiology of Paget’s disease of bone, including abnormal osteoclast and osteoblast activity.

• Recognize the epidemiology and risk factors associated with Paget’s disease.

• Identify common clinical manifestations, including bone pain, deformities, and complications such as hearing loss.

Learning Objectives

Case Relevance

We concluded that it was unlikely that the patient had Pagets disease of the bone but it was included in our differential

Poll

• A

• B

• C

• D

• E

Etiology

• Prevalence: > 50 years of age

• Ethnicity: Common in Caucasians of Northern European Descent

• Sex: ♂ > ♀ (1.2:1)

• Age of onset: > 55 years

• 70-90% Asymptomatic

• Increased ALP

Pathophyisology

• Idiopathic disease

• The pelvis, skull, vertebral column, and long bones of the lower extremities are most commonly affected

• Associated with a high rate of bone remodeling

  • Increased RANKL-RANK -> Increased NF-kB -> Increased osteoclast/blast activity -> disorganized bone formation

Pathophysiology

​Stages

• Lytic phase

  • Increased number of osteoclasts activated -> bone resorption

• Mixed phase

  • Increased osteoclast activity with an increase in the number of osteoblasts -> increase in abnormal hypervascular bone formation

• Scelerotic Phase

  • Osteoblast activity overtakes osteoclast activity -> dense sclerotic bone formation.

• Quiescent stage

  • Both osteoclast and osteoblast activity stop

References

• Bouchette P, Boktor SW. Paget Bone Disease. [Updated 2023 Nov 12]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK430805/

• Clark KEN, Jawad ASM. Sabre tibia in Paget's disease of bone. Rheumatol Adv Pract. 2023;7(1):rkad032. Published 2023 Mar 25. doi:10.1093/rap/rkad032

• Lasanianos, N.G., Kanakaris, N.K. (2015). Paget’s Disease. In: Lasanianos, N., Kanakaris, N., Giannoudis, P. (eds) Trauma and Orthopaedic Classifications. Springer, London. https://doi.org/10.1007/978-1-4471-6572-9_118

• Paget disease of bone: Nursing: Video & causes | osmosis. Osmosis. Accessed September 3, 2025. https://www.osmosis.org/learn/Paget_disease_of_bone:_Nursing.