rheumatology and orthopaedics

Question 1

what is Paget’s disease a disorder of

Answer 1

bone turnover

Question 2

3 stages of Paget’s disease

Answer 2

osteolytic (osteoclast), osteolytic-osteosclerotic (osteoblast respond, while osteoclasts continue), quiescent osteosclerotic (both cells form mosaic pattern)

Question 3

prevalence of Paget’s disease

Answer 3

onset over 40 (affects 3-8% Caucasians over 55); more prevalent in males; rare in Asians and Africans; mono-ostotic 15% (affects one bone), with remainder polyostotic

Question 4

pattern of inheritance of Paget’s disease, including mutations

Answer 4

aetiology unknown, but autosomal inheritance, with incomplete penetrance (mutations in SQSTM1 or RANK)

Question 5

other possibility of Paget’s disease causes

Answer 5

overuse or previous bone injury

Question 6

most common bones affected

Answer 6

skull, vertebrae, ribs, femur, pelvis, humerus, tibia and fibula

Question 7

9 clinical symptoms of Paget’s disease

Answer 7

pain, microfractures, nerve compression (including spinal nerve and cord), skull changes may put medulla at risk, deafness, +/- haemodynamic changes and cardiac failure, hypercalcaemia, development of sarcoma in area of involvement 1%, raised serum alkaline PO4, urinary hydroxyproline, pyridinoline cross-links

Question 8

Paget’s disease affecting femur

Answer 8

small lytic lesions in medullary canal, with osteoclasts absorbing trabeculae away, forming mosaic pattern of quiescent osteosclerotic phase

Question 9

radiological signs of Paget’s disease (normally caught in last 2 sclerotic phases)

Answer 9

cortical thickening; bone expansion; coarsening of trabeculae; osteolytic (lucency), osteoclerotic and mixed lesions; osteoporosis circumscripta (large dark aresa in skull in osteolytic phase, which looks thickened due to cortical thickening)

Question 10

how many bones does Paget’s disease affect

Answer 10

one bone, as it doesn’t jump across the joint