Paget disease of bone
Paget disease of bone is a common, localized disorder of accelerated, disorganized bone remodeling that raises serum alkaline phosphatase with normal calcium and phosphate, usually diagnosed incidentally, and treated with a single dose of intravenous zoledronic acid when bone pain, high-risk sites, or marked alkaline phosphatase elevation are present.
- Topic reviewThe full article, organized the way the exam asks it.
- ABIM-format MCQsVignettes with an explanation for every wrong answer.
- Key factsThe numbers and thresholds worth memorizing, up front.
- AI tutorMedBrain answers the question you're stuck on.
What this article covers
- Overview
A common, localized disorder of disorganized bone remodeling, with increased osteoclastic bone resorption followed by increased osteoblastic bone formation that produces structurally poor-quality bone.
- Epidemiology
Prevalence about 3% of the US population older than 45 years.
- Risk factors
Older age, the dominant epidemiologic association, with prevalence concentrated after age 45 years.
- Pathophysiology
Increased osteoclastic bone resorption is followed by a compensatory increase in osteoblastic bone formation, producing bone that is structurally disorganized rather than simply increased in quantity.
- Clinical features
Most patients are asymptomatic, with disease discovered through an incidentally elevated alkaline phosphatase level or radiographic abnormality; this is the single most common presentation.
- Differential diagnosis
Osteoblastic bone metastases (for example prostate cancer): elevated alkaline phosphatase with a diffuse or multifocal pattern and an elevated tumor marker (such as prostate-specific antigen), unlike…
- Diagnosis
The diagnostic basis, established first, is an elevated serum alkaline phosphatase with normal serum calcium, phosphate, and 25-hydroxyvitamin D, combined with the characteristic radiographic…
- Management
First, determine whether treatment is indicated: bone pain; disease at a high-risk site (skull, spine, weight-bearing bone, or bone near a joint) where complications could occur; or a markedly…
- Complications
Bone deformity and pathologic (chalk-stick) fracture from disorganized, structurally weak bone.
- Prognosis
Most patients have a good prognosis and require only monitoring, since the disease is often asymptomatic and localized.
- Prevention
No primary prevention exists, since pathogenesis is not fully understood and no modifiable risk factor has been identified.
Read the whole article
Subscribing to Internal Medicine opens every article, the full question bank and MedBrain, on the web, iPhone and Android.
Related articles
- Hypercalcemia
Hypercalcemia is an elevated serum calcium concentration, most often caused by primary hyperparathyroidism in ambulatory patients or malignancy in hospitalized patients. Mild disease requires only treatment of the underlying cause, while severe or symptomatic hypercalcemia is treated with aggressive IV isotonic fluids, followed by an IV bisphosphonate or denosumab for sustained control and subcutaneous calcitonin as a rapid but short-lived bridge.
- Osteosarcoma
Osteosarcoma is a malignant osteoid-producing bone tumor with a bimodal age distribution, most often arising in the metaphysis around the knee in adolescents and young adults. Diagnosis rests on radiograph findings of Codman triangle or sunburst periosteal reaction confirmed by biopsy, and treatment sequences neoadjuvant chemotherapy, limb-sparing wide resection, and adjuvant chemotherapy.
- Multiple myeloma
Multiple myeloma is a clonal plasma cell neoplasm that produces a monoclonal immunoglobulin and end-organ damage summarized by CRAB (hypercalcemia, renal failure, anemia, bone lesions), diagnosed by marrow clonal plasma cells of 10% or more plus a CRAB or SLiM myeloma-defining event. Treatment combines a proteasome inhibitor, an immunomodulatory drug, and dexamethasone, followed by autologous stem cell transplant and maintenance in eligible patients.
- Osteoporosis
Osteoporosis is low bone strength that raises fragility fracture risk, diagnosed by a hip or spine T-score of -2.5 or less or by a fragility fracture itself. First-line treatment is an oral bisphosphonate, alendronate or risedronate, alongside adequate calcium and vitamin D intake.
- Hearing loss
Hearing loss is evaluated with the Weber and Rinne tuning fork tests to sort conductive from sensorineural loss at the bedside, then confirmed with audiometry; treatment ranges from cerumen removal or hearing aids to urgent oral prednisone and otolaryngology referral for sudden sensorineural loss.
- Vertebral compression fracture
A vertebral compression fracture is a collapse of the anterior or middle vertebral body, most often from osteoporotic fragility with minimal or no trauma, presenting as acute focal spinal tenderness or, in up to two-thirds of cases, as an asymptomatic finding on imaging. Diagnosis is by spine radiograph confirming the fracture, which alone establishes a clinical diagnosis of osteoporosis, and first-line management is analgesia (acetaminophen 650 mg PO every 6 hours) with antiresorptive or anabolic pharmacotherapy to prevent further fracture.