Metabolic Bone Diseases (Osteoporosis, Osteomalacia, Paget's) MCQs

Orthopedics · 46 free questions with answers & explanations.

1. A 70-year-old woman sustains a vertebral compression fracture spontaneously. DXA scan shows a T-score of -2.8. Serum calcium, phosphate, and alkaline phosphatase are normal. The most appropriate primary treatment is:
2. A 68-year-old man presents with progressive bowing of the right tibia, skull enlargement requiring larger hat size, and bilateral sensorineural hearing loss. Serum alkaline phosphatase is markedly elevated with normal calcium and phosphate. The diagnosis is:
3. A 70-year-old woman with osteoporosis (T-score −2.8) sustains a vertebral compression fracture. She is currently on alendronate. Lab shows elevated serum alkaline phosphatase. Which drug from the bisphosphonate class has the highest potency (relative antiresorptive activity) and is administered as a once-yearly infusion?
4. A 65-year-old man with Paget's disease presents with progressive bowing of the left femur and recent increase in pain. ALP is massively elevated (1800 U/L). X-ray shows coarsened trabeculae, cortical thickening, and advancing 'blade of grass' or 'flame-shaped' lytic front in the femoral shaft. The most feared complication of Paget's disease that requires urgent monitoring is:
5. A 45-year-old woman from rural India presents with diffuse bone pain, proximal muscle weakness, and waddling gait. Lab shows: Ca 7.2 mg/dL, Phosphate 2.0 mg/dL, ALP 580 U/L, PTH elevated, 25-OH Vitamin D <10 ng/mL. X-ray shows Looser's zones (pseudofractures) at the medial femoral neck. Looser's zones are pathognomonic of:
6. A 70-year-old postmenopausal woman with a DXA T-score of -2.7 at the femoral neck sustains a fragility fracture. FRAX tool calculation gives a 10-year probability of major osteoporotic fracture of 22%. The MOST appropriate pharmacological treatment is:
7. In Paget's disease (osteitis deformans), the characteristic change in serum biochemistry is:
8. Looser's zones (pseudofractures) seen on X-ray in osteomalacia are pathologically caused by:
9. A 65-year-old postmenopausal woman has a T-score of -2.7 on DXA at the femoral neck, a FRAX 10-year probability of major osteoporotic fracture of 18%, and has had one prior fragility fracture of the wrist. According to current treatment guidelines (NICE/IOF), the most appropriate pharmacological management is:
10. In Paget's disease of bone, the most feared orthopaedic complication and the most common orthopaedic presentation respectively are:
11. Looser's zones (Milkman's fractures) in osteomalacia are linear radiolucent zones that occur perpendicular to the cortex. They are characteristically found at which anatomical sites?
12. A 72-year-old woman on long-term bisphosphonate therapy for osteoporosis presents with thigh pain for 2 months. X-ray shows a transverse cortical stress fracture of the subtrochanteric femur with lateral cortical beaking. This pattern is MOST consistent with:
13. A 65-year-old man with Paget's disease of bone presents with low back pain. Serum alkaline phosphatase is markedly elevated. X-ray of the pelvis shows a 'picture frame' appearance of the right ilium and cortical thickening. Which bone complication of Paget's disease carries the WORST prognosis?
14. A 70-year-old postmenopausal woman has a T-score of −2.7 at the hip with a 10-year FRAX major osteoporotic fracture probability of 18%. She had a previous fragility wrist fracture. Pharmacological treatment is initiated. Which drug has a DUAL mechanism of both inhibiting bone resorption AND stimulating bone formation?
15. In Paget's disease of bone, the osteitis deformans stage is characterised by osteoclastic overactivity. The radiological sign of a 'blade of grass' or 'flame-shaped' lytic lesion advancing along the diaphysis is specifically seen in which bone?
16. In Paget's disease of bone affecting the tibia, the characteristic X-ray finding at the advancing edge of the lytic front is best described as:
17. A 35-year-old on long-term phenytoin develops proximal muscle weakness, bone pain, and X-ray shows Looser's zones (Milkman's fractures) in the femoral necks bilaterally. Serum calcium is low, phosphate low, and ALP elevated. Which is the pathogenetic mechanism of this osteomalacia?
18. A 70-year-old postmenopausal woman with DXA T-score of -2.8 at the femoral neck has a 10-year FRAX probability of major osteoporotic fracture of 22%. She has already sustained a vertebral compression fracture. What is the first-line pharmacological treatment?
19. A 65-year-old male is found to have Paget's disease of bone (polyostotic) on X-ray. Which biochemical parameter is the MOST sensitive marker for monitoring disease activity and treatment response?
20. A 72-year-old woman sustains her second vertebral compression fracture in 18 months while on alendronate. She has chronic kidney disease (eGFR 25 mL/min/1.73m²). Which anti-osteoporotic agent is CONTRAINDICATED at this eGFR level?
21. In Paget's disease of bone, the pelvis is the most commonly affected bone. A 68-year-old man with known Paget's disease presents with new onset rapidly worsening hip and thigh pain. X-ray shows a lytic 'flame-shaped' lesion within the pagetic femur with cortical destruction. Serum alkaline phosphatase is markedly elevated (baseline 850 IU/L, now 2200 IU/L). What complication must be immediately suspected and how is it confirmed?
22. Paget's disease of bone presenting as bowing deformity of the tibia (saber tibia) with a 'banana fracture' risk. The incomplete stress fractures typically occur on which cortex, and what is the implication for prophylactic management?
23. A 65-year-old postmenopausal woman on long-term alendronate (7 years) presents with prodromal thigh pain and a transverse 'beaking' cortical stress reaction at the lateral subtrochanteric femur. This presentation is consistent with:
24. A 70-year-old man has Paget's disease affecting the proximal tibia. Serum calcium, phosphate, and PTH are normal. Serum alkaline phosphatase (ALP) is markedly elevated at 850 IU/L. He develops progressive leg bowing. Which complication carries the highest mortality risk in advanced Paget's disease?
25. A 55-year-old postmenopausal woman has a DXA T-score of −2.8 at the lumbar spine. She sustains a low-energy vertebral compression fracture. She is started on alendronate. What is the mechanism of action of bisphosphonates in osteoporosis?
26. A 70-year-old woman with Paget's disease of bone presents with bowing of the left femur, hearing loss, and serum alkaline phosphatase of 950 U/L. The most sensitive biochemical marker for monitoring treatment response to bisphosphonate therapy in Paget's disease is:
27. A 65-year-old woman has a DEXA scan T-score of -2.8 at the lumbar spine. She has no prior fragility fracture. According to WHO criteria, she has:
28. A 70-year-old woman with a T-score of -3.2 at the femoral neck sustains a fragility fracture of the distal radius. She is started on alendronate 70 mg weekly. After 5 years of treatment, she is reassessed. When should a drug holiday (temporary discontinuation) be considered for oral bisphosphonates?
29. A 68-year-old man presents with increasing hat size, hearing loss, and bone pain. Serum alkaline phosphatase is markedly elevated. Bone scan shows intense uptake in the skull, pelvis, and right femur. The complication most feared in Paget's disease of bone involving a long bone is:
30. A 72-year-old woman sustains a low-energy hip fracture. DEXA scan shows T-score of −2.9 at the femoral neck. She is initiated on alendronate (bisphosphonate therapy). The primary mechanism of action of bisphosphonates is:
31. A 65-year-old male with Paget's disease of bone develops bone pain, deformity, and elevated alkaline phosphatase (ALP). The most feared malignant complication of Paget's disease is:
32. A 68-year-old woman being treated with oral bisphosphonates for 8 years develops a stress fracture of the femoral shaft at the subtrochanteric region. Radiograph shows a 'beak' or 'flare' cortical thickening on the lateral cortex with a transverse incomplete fracture line. This is classified as:
33. A 74-year-old man with known Paget's disease of bone develops worsening thigh pain. Serum alkaline phosphatase, previously elevated at 400 IU/L, has recently risen to 1800 IU/L. Radiograph shows destruction of the previous pagetic pattern with cortical breakthrough and a soft tissue mass. The most likely diagnosis is:
34. Paget's disease of bone causes characteristic 'flame-shaped' ('V-shaped' or blade-of-grass) lytic lesion advancing through the tibial cortex. This represents:
35. A patient on long-term bisphosphonate therapy (8 years for osteoporosis) develops sudden bilateral thigh pain after minimal exertion. Radiographs show bilateral focal lateral cortical thickening (beaking) of the subtrochanteric femoral shaft. The diagnosis is:
36. A 78-year-old woman on long-term bisphosphonate therapy (8 years of alendronate) presents with a complete transverse fracture of the subtrochanteric region with a medial spike (beaking), lateral cortical thickening seen on prior X-rays. This pattern of fracture is best classified as:
37. Paget's disease of bone involves a markedly elevated serum alkaline phosphatase with normal calcium and phosphate. The cell type primarily hyperactive in the lytic phase and responsible for the elevated alkaline phosphatase is:
38. A 70-year-old woman on long-term bisphosphonate therapy (alendronate 10 years) presents with a fracture of the subtrochanteric femur after minimal trauma. X-ray shows a transverse fracture with cortical thickening ('beaking') of the lateral cortex. This pattern is most consistent with:
39. In Paget's disease of bone involving the proximal femur, the pathological stress fracture on the lateral (convex) cortex of the anterolaterally bowed femur (sabre tibia equivalent) is called a:
40. A 70-year-old woman with established osteoporosis (T-score −3.2) has sustained two vertebral fractures in the past 2 years despite taking alendronate 70 mg weekly for 3 years. Her bone turnover markers remain elevated. The most appropriate next pharmacological intervention is:
41. A 68-year-old man presents with bowing of the right tibia, right tibial pain, and a raised alkaline phosphatase (ALP) of 620 IU/L with normal serum calcium and phosphate. Skull X-ray shows 'cotton wool' appearance. A bone scan shows intense uptake in the right tibia and skull. The complication of Paget's disease that occurs in this bone over 1% of cases is:
42. A 3-year-old child is brought with bow legs (genu varum). X-ray shows widened, frayed, and cupped metaphyses of the distal radius, ulna, and knee. Serum calcium is low, phosphate is low, and alkaline phosphatase is markedly elevated. What is the diagnosis and the most important deficiency?
43. A newborn is noted to have blue sclerae, multiple fractures, and excessive joint laxity. The parents are unaffected. Which type of osteogenesis imperfecta (OI) does this most likely represent, and what is the underlying defect?
44. A 12-year-old obese boy has a painful limp and limited internal rotation of the right hip. X-ray shows posterior and medial displacement of the right femoral head relative to the femoral neck on the frog-leg lateral view. What is the diagnosis, and what is the immediate management?
45. A 5-year-old boy presents with a limp and mild hip pain for 3 weeks. X-ray shows increased density of the femoral head with a crescent sign (subchondral lucency). ESR is normal and the child is afebrile. What is the most likely diagnosis?
46. A 60-year-old postmenopausal woman on long-term oral bisphosphonate therapy for osteoporosis develops sudden thigh pain and an X-ray shows a transverse fracture of the lateral cortex of the subtrochanteric femur with medial cortical thickening and a 'beaking' pattern. This is best classified as: