ETIOLOGY
- Unknown
- Genetic component:
- SQSTM1 mutation seen in many but not all cases
- Environmental influences may also play a role
- Presence of nucleocapsids from measles, canine distemper, paramyxovirus, or respiratory syncytial virus may implicate viral cause
- Possible association with rural life and close contact with farm animals
- May represent vascular hyperplasia with subsequent inflammation
- Increased nucleoli and intranuclear inclusion bodies seen in osteoclasts on microscopy
Pediatric Considerations
Generally not seen in children
DIAGNOSIS
SIGNS AND SYMPTOMS
- Many patients are asymptomatic, with disease discovered by incidental radiographs or elevated alkaline phosphatase levels
- Deep, aching bone pain occurs late in the clinical course
- Pain with weight bearing if femur or tibia involvement
- Pain worse with rest in nonweight-bearing bones
- Acute (resorptive/osteolytic) phase:
- Pathologic fractures
- Pain from acute lysis, fracture, or resultant arthritis
- Hypercalcemia or renal stones
- Hypervascularity may result in significant bleeding if affected bone is fractured
- Widespread disease:
- Increased vascularity and blood flow may result in high-output cardiac failure
- Secondary (sclerotic/osteoplastic) phase:
- Long-bone involvement may present with swelling or deformity and gait abnormality
- Skull involvement may cause headaches or abnormal skull shape (change in hat size)
- Severe skull or spine involvement may result in CNS compression
- Hearing loss may result from nerve compression or ossicle involvement
ESSENTIAL WORKUP
- Diagnosis usually suggested by radiographs
- Thorough neurologic exam must be documented, especially with vertebral or pelvis involvement
DIAGNOSIS TESTS & NTERPRETATION
Lab
- Alkaline phosphatase is the most dramatic marker of disease activity
- Calcium and phosphate levels should be checked as well, but are usually normal
- Hypercalcemia seen in immobilization or presence of a fracture, but if elevated in an ambulatory patient, suspect hyperparathyroidism
- EKG if suspect hypercalcemia and CXR with evidence of high-output cardiac failure
- Increased bone formation may lead to elevations in urine hydroxyproline or serum osteocalcin or procollagen fragments
- Alterations in parathyroid hormone (PTH) levels occur as secondary changes during resorptive/osteolytic phase (low PTH) and sclerotic/osteoplastic phase (high PTH)
Imaging
- Plain x-rays:
- During resorptive phase, lytic lesions are often not seen, except in skull, where lesions are well demarcated (osteoporosis circumscripta)
- Bowing of long bones may occur with resorption and strength loss
- New bone initially appears irregular and spotty, and later becomes homogeneous and dense (“ivory pattern”)
- Excess bone may be deposited along stress lines, leading to cortical irregularities and thickening
- CT or MRI defines margins and helps evaluate for neoplasm or hematoma:
- Spiral CT to detect renal calculi
- Radionuclide bone scans useful to evaluate extent and activity of disease
- Plain films are usually all that is needed in acute setting to identify/manage fractures
DIFFERENTIAL DIAGNOSIS
- Primary hyperparathyroidism
- Multiple myeloma
- Hodgkin variants
- Acromegaly
- Osteosarcoma
TREATMENT
PRE HOSPITAL
- Pre-hospital personnel should obtain information about mechanism of injury or social factors that suggest pathologic fracture
- Adequate immobilization can limit excessive bleeding around fracture site
INITIAL STABILIZATION/THERAPY
- Airway management and resuscitation, as indicated
- High-output cardiac failure should be treated as outlined in CHF chapter
- Prompt immobilization of fractures will limit excessive bleeding around fracture site
ED TREATMENT/PROCEDURES
- Analgesia for pain of lytic lesions, fractures, or arthritis includes acetaminophen and narcotics
- Fracture treatment is often more conservative, owing to difficulties with bleeding during operative repair
- Orthopedic consultation for severe arthritis and definitive fracture management
- Hypercalcemia may be treated with IV fluids, calcitonin, and/or bisphosphonates
- CNS compression requires emergent neurosurgical consultation and possible decompression
MEDICATION
Treatment indicated in patients with symptomatic disease or asymptomatic disease located in areas where complications can occur
First Line
- Nitrogen-containing bisphosphonates:
- Pamidronate: 30 mg IV daily × 3 consecutive days; infuse over 4 hr
- Alendronate: 40 mg PO daily for 6 mo
- Risedronate: 30 mg PO daily for 2 mo
- Zoledronic acid: 5 mg IV × 1; infuse over at least 15 min
Second Line
- Simple bisphosphonates and calcitonin:
- Etidronate: 5 mg/kg PO daily for 6 mo
- Tiludronate: 400 mg PO daily for 3 mo
- Calcitonin: 50–100 U SC as tolerated; not for >6 mo
- Chemotherapy and simple bisphosphonates no longer recommended
- Use of calcitonin and simple bisphosphonates are limited to patients who cannot tolerate or who are allergic to the nitrogen-containing bisphosphonates
- Side effects of bisphosphonates include influenza like syndrome and jaw osteonecrosis
- Often need supplemental vitamin D and Ca to maintain normal Ca levels during treatment
FOLLOW-UP
Admission Criteria
- Admission as indicated for major trauma or injury, or excessive bleeding
- Orthopedic procedures
- Hypercalcemia
- CNS compressive symptoms, nerve entrapment requiring surgery
Discharge Criteria
- No evidence of significant bleeding, neurologic compromise, or hypercalcemia, and adequate pain control
- Appropriate fracture immobilization and orthopedic follow-up
Issues for Referral
- Referral is based upon any acute injuries
- May also consider referral to endocrinologist within 1–2 wk of discharge
FOLLOW-UP RECOMMENDATIONS
- Follow-up is generally driven by the acute injury that led to the radiographs on which the diagnosis of Paget disease was made
- Response to pharmacologic treatment aimed at correction of serum alkaline phosphatase levels
- Consider repeat pharmacologic treatment if rise in serum alkaline phosphatase, return of symptoms, or disease progression seen radiographically
PEARLS AND PITFALLS
- The diagnosis of Paget disease is usually made as an incidental finding on radiographic imaging
- Prompt immobilization of fractures will limit excessive bleeding around fracture site
- Consider Paget disease if elevation of alkaline phosphatase is present without any other explanation
ADDITIONAL READING
- Cundy T, Reid IR. Paget’s disease of bone.
Clin Biochem.
2012;45:43–48.
- Lojo Olivieria L, Torrijos Eslava A. Treatment of Paget’s disease of bone.
Reumatol Clin.
2012;8:220–224.
- Ralston SH, Langston AL, Reid IR. Pathogenesis and management of Paget’s disease of bone.
Lancet
. 2008;372:155–163.
- Whyte MP. Clinical practice. Paget’s disease of bone.
N Engl J Med
. 2006;355:593–600.
See Also (Topic, Algorithm, Electronic Media Element)
Specific Orthopedic Injuries
CODES
ICD9
731.0 Osteitis deformans without mention of bone tumor
ICD10
- M88.9 Osteitis deformans of unspecified bone
- M88.88 Osteitis deformans of other bones
- M88.859 Osteitis deformans of unspecified thigh