Pathology

1. Metabolic bone disease: increased bone turnover - increased osteoblast and osteoclast activity
   • Genetic: mechanism unclear ?chromosome 18q
   • Infectiou: paramyxovirus
2. Leads to bone enlargment, deformity and weakness 

Approach

• Expose legs
• Preserve dignity

1. Inspection
   • Anterior bowing of tibia (sabre tibia)

   • 
   • Lateral bowing of femur
2. Palpation
   • Affected bone for warmth

Completion

1. Examine skull circumference (>55cm abnormal)
2. Ask patient if they have difficulty hearing (VIII compression)
3. OA of hip
4. Neck: JVP - high output failure

Biochemical features of Paget's disease

• Normal serum calcium (occasionally raised)
• Raised ALP
• Increased Hydroxyproline secretion (due to increased bone resorption)

Complications of Paget's disease

1. Bone
   • Deformity
   • Pathological fractures
   • Sarcomatous change - 1% osteosarcoma
2. Neurological
   • Cranial nerve palsies
3. Cardiac
   • High output cardiac failure

Treatment of Paget's disease

1. Symptoms (usually asymptomatic)
   • Analgesia
2. Specific
   • Bisphosphonates - inhibit osteoclast bone resorption
   • Calcitonin - inhibit osteoclast activity
3. Surgical
   • Arthroplasty

Radiological features of Pagets

Skull		Honeycomb / cottonwool appearanace with underlying osteoporosis circumscripta
Vertebrae		Picture frame appearance
Pelvis		"Brim sign" due to thickening of iliopectineal line Enlargement of ischial and pubic bones
Long bones		Increased trabeculation