Introduction

Paget disease (Osteitis deformans) is a chronic, localized bone-remodeling disorder of abnormal osteoclasts that drive increased bone resorption accompanied by accelerated, disordered bone formation that results in disorganized, fragile bone

-It was originally described by Sir James Paget in 1877 

-It most commonly involves the pelvis, vertebrae, skull, humerus, femur and tibia 

-it predominantly affects Caucasian individuals over the age of 40 

Symptoms & Signs 

-Most patients are asymptomatic 

-Most common presenting symptom is pain, often worse at night  

-Bowing of weight-bearing bones, stress fractures (Chalk stick fractures), 

-Enlargement of the parietal or frontal bones (frontal bossing), increased head size, softening of the base of the skull (platybasia)

Complications of Paget disease: 

Rheumatologic: Osteoarthritis, gout, vertebral collapse 

Neurologic: Basilar impression, peripheral nerve entrapment, spinal cord and root compression 

Otologic: Cranial nerve dysfunction (especially deafness) 

Ophthalmic: Loss of vision 

Neoplastic: Osteosarcoma, giant cell tumor 

Cardiac: High-output heart failure 

Metabolic: Hypercalcemia 

Diagnosis 

X rays: Focal lytic, radiolucent areas with a coarse trabecular pattern and bone thickening, described as osteoporosis circumscripta “cotton-wool” skull, enlarged “picture-frame” vertebrae, “ivory vertebrae”

Labs: Normal calcium, phosphate levels, Elevated serum alkaline phosphatase

Bone resorption markers: Elevated serum or urine N-telopeptide or C-telopeptide measured in the blood or urine

Treatment 

-Adequate calcium and vitamin D intake 

-Mainstay of pharmacologic therapy: Bisphosphonates 

-The treatment of choice: Zoledronic acid 

-Other medications: Pamidronate, Risedronate, Alendronate, Tiludronate

-Serial serum alkaline phosphatase determinations are done to evaluate the response to treatment