On this page
Study tools
Write your answer
Saved on this device. No marking — you are the marker.
Q1: Definition and recognition (2 min)
Examiner: Define Paget disease of bone. How would you recognise it clinically?
Expected answer:
- Paget disease of bone (osteitis deformans) is a chronic, FOCAL (not systemic) disorder of adult bone remodeling in which disordered, excessive osteoclast activity is followed by chaotic osteoblastic repair.
- The result is thick but mechanically weak woven (mosaic) bone.
- Often asymptomatic — picked up on incidental raised alkaline phosphatase with normal calcium and phosphate.
- Symptomatic: deep aching bone pain, deformity (bowing, enlarging skull, kyphosis), hearing loss, and warmth over affected bone.
- Common sites: pelvis, spine, skull, femur, tibia; most common in elderly Anglo-Saxon populations and rare under 40.
Q2: Investigations (3 min)
Examiner: How do you confirm Paget disease?
Expected answer:
- Biochemical signature: raised alkaline phosphatase with NORMAL calcium and NORMAL phosphate (and normal renal function); check the gamma-GT to confirm a bone rather than liver source.
- Plain X-rays: cortical thickening, bone expansion, mixed lytic-sclerotic lesions, cotton-wool skull, osteoporosis circumscripta, blade-of-grass lytic edge, picture-frame vertebrae, bowing.
- Technetium-99m isotope bone scan: the most sensitive test for extent — focal hot spots map the number and location of sites.
- Check 25-hydroxyvitamin D before treatment; bone-specific ALP / P1NP quantify turnover; audiometry for hearing.
- MRI and biopsy only if osteosarcoma is suspected (new or escalating pain, cortical destruction, soft-tissue mass).
Q3: Management (3 min)
Examiner: Walk me through the treatment.
Expected answer:
- Who to treat: symptomatic bone pain, risk of complication (fracture, deafness, neurological), before elective surgery at a Pagetoid site, young patients, or active disease with a markedly raised ALP.
- First-line: a SINGLE 5 mg intravenous zoledronate infusion — the most potent bisphosphonate, normalising ALP for months to years.
- Oral risedronate is an alternative; etidronate is avoided (impairs mineralisation).
- Calcium and vitamin D must be repleted before and after bisphosphonate therapy to prevent hypocalcaemia.
- Symptom support: analgesia, physiotherapy, walking aids, hearing aid.
- Pre-treat a Pagetoid site with a bisphosphonate before elective orthopaedic surgery to reduce hypervascular operative bleeding.
- Monitor alkaline phosphatase to track response; re-treat on relapse.
Q4: Complications and the key danger (2 min)
Examiner: What are the complications — and what is the single most feared one?
Expected answer:
- Pathological fracture through weak Pagetoid bone; secondary osteoarthritis of adjacent joints.
- Deafness (sensorineural, skull-base / cochlear and 8th-nerve involvement).
- High-output cardiac failure in extensive hypervascular disease.
- Spinal cord or nerve-root compression from vertebral Paget; basilar invagination (platybasia).
- The most feared complication is osteosarcoma transformation (rare, under 1 percent), heralded by NEW, SEVERE or RAPIDLY WORSENING pain ± a soft-tissue mass — requiring urgent imaging and biopsy and carrying a poor prognosis.