PAGET’S DISEASE

Osteitis Deformans

Paget’s disease

Is a state of increase metabolic activity in the bone characterized by excessive

bone remodeling,

both resorption and formation.

• Named after Sir James Paget (1814-1899)

• First described osteitis deformans in 1877

Bone Remodeling Cycle Phase 1 (activation)

a stimulus activates the bone cells precursors in the localized area of the bone to form osteoclasts.

Phase 2. (resorption)

osteoclast forms a “cutting cone” which gradually resorb bone, leaving behind and elongated cavity.

Phase 3 (formation)

laying down of new bone by osteoblast lining the walls of the resorptive cavity.

Bone Remodeling Cycle

Etiology

The possible causes are many, but no exact etiology has been defined.

– Genetic factor (Sequestrosome 1 gene on chromosome 5)

– Virus infection may be necessary to trigger

– Chronic infection (Osteitis Deformans)

– Hormonal dysfunction

– Autoimmune states

Histological features

• Osteoclasts are enlarged

• Increased bone turnover produces a mosaic pattern of lamellar bone

• Three phases recognised - osteolytic, mixed and sclerotic

• Osteolytic or Destructive Phase– Initial phase marked by extensive

resorption of existing bone

• Mixed or Active Phase– Osteoclasts destroy the ordered lamellar

bone and osteoblast respond to the destruction by rapid disposition of vascular connective tissue and remodeled lamellar bone

• Sclerotic or Osteoblastic Phase– last phase wherein bone formation outstrips

resorption

Paget’s diseasePathophysiology

EtiologyHormonal

DysfunctionAutoimmune StatesViral CausationChronic InfectionGenetic Factor (Sequestrosome 1 gene on chromosome 5)

↑Ca ECF

Compensatory Mechanism

Hyperactivity of osteoclasts

Osteoclast destroys

lamellar bone

Increase extensive resorption

↑ osteoblast response

Rapid disposition of vascular connective

tissue

Increase bone formation

Increase bone size and thickness

• Bone pain • Spinal stenosis• Numbness• Weakness• (Skull)

headaches, dizziness, facial droop with vision or hearing impairment

• Bowing of legs• Curve

backbone

•Skull enlargement bitemporally and frontally•Enlargement of pelvis

Compressionof nerves

Poorly mineralized

bones

Overgrown bone

Signs & Symptoms

• There are usually no symptoms for a prolonged period.

– If symptoms occur, they develop insidiously, with pain, stiffness, fatigue, and bone deformity.

– Bone pain is aching, deep, and occasionally severe, sometimes worse at night.

– Pain also may arise from compression neuropathy or osteoarthritis.

• Signs may include:

– Spine: curve backbone nerves can become damaged and cause leg pain, numbness, weakness, or cauda equina syndrome (an emergency condition with symptoms that include loss of feeling in the pelvic area and legs)

• Skull: skull enlargement bitemporally and frontally (frontal “bossing”); dilated scalp veins; headaches, dizziness, loss of muscle strength in the face (facial droop), or problems with vision or hearing.

• Bowed legs, Enlarged pelvis

Radiological features• Osteolytic phase can produce osteoporosis

circumscripta (localized cranial osteoporosis)

• Bone softening can produce bowing, platybasia, protrusion acetabuli or greenstick fractures

• Mixed phase shows generalized bone enlargement

• Sclerotic phase shows increased density, trabeculae and cortical thickening

Complications

• Pathological fractures - complete or incomplete

• Neurological effects – Cranial nerve lesions

– Spinal cord lesions

• Osteoarthritis

• Sarcomas

Biochemistry

• Serum calcium and phosphate are usually normal

• Serum alkaline phosphatase is increased

• Uric acid increased in about 30% of patients

Diagnosis• Plain x-rays and radioisotopes bone scan

– Increased bone sclerosis

– Abnormal architecture with coarse cortical trabeculation or cortical thickening

– Bowing

– Bony enlargement

• Serum alkaline phosphatase, Ca, and PO4

• Bone scan after diagnosis established

Nursing Diagnosis

1. Acute pain related to impingement of abnormal bone on spinal cord

2. Bathing/hygiene, dressing/grooming, toileting self-care deficit related to musculoskeletal impairment

3. Disturbed body image related to bowing of legs.

4. Impaired physical mobility related to asymmetrical bowing of tibia and femur