Diagnosis of osteoporosis

short notes regarding osteoporosis diagnosis

1. Diagnosis of osteoporosis Clinical, Radiological and Biochemical tools Dr. Shorouk Issa Associate lecturer of Endocrinology and Metabolism Al Azher University-Egypt

2. Diagnosis of osteoporosis Clinical presentation Radiological investigations Biochemical tools

3. Clinical manifestations Osteoporosis has no clinical manifestations until there is a fracture . Fractures of the spine and hip that occur in absence of major trauma.

4. However there are some clinical features that should draw attention to the presence of osteoporosis:- Thoracic kyphosis loss of Height Active and passive range of motion (ROM) Pain, or pain free. Neurologic examination is essential to rule out spinal cord and/or peripheral nerve compromise.

5. Radiological tools (Bone densitometry) The diagnosis of osteoporosis relies on the quantitative assessment of bone mineral density (BMD), which is currently considered the best predictor of osteoporotic fractures.

6. What is BMD? Bone mineral density (BMD) value is the amount of bone mass per unit volume (volumetric density), or per unit area (areal density), and both can be measured  in vivo  by densitometric techniques. BMD is determined by measuring the amount of bone mineral ( calcium hydroxyapatite Ca 10  (PO 4 ) 6  (OH) 2 ) per unit volume of bone tissue.

7. Femur neck BMD can predict hip fracture, Lumbar spine BMD predicts vertebral fractures

8. T-score and Z-score   BMD can be expressed as a T-score and a Z-score, which represent the number of standard deviations (SDs) with respect to a reference average value. T-scores are calculated by taking the difference between a patient’s measured BMD and the mean BMD in healthy young adults, matched for gender and ethnic group, and expressing the difference relative to the young adult population standard deviation (SD):

9. Z-score Z-scores is the BMD of the patient compared with the mean BMD expected for the patient’s peers

10. Groups That Should Be Tested for BMD All women over the age of 65 All w omen during the menopausal transition with risk factors for fracture All Postmenopausal women All individuals over the age of 50 who suffer an osteoporotic fracture

11. Groups That Should Be Tested for BMD All individuals who are taking long term corticosteroids(7.5mg of prednisone daily for 3m) All men over the age of 65 Men with hypogonadism Patients with diseases associated with bone loss and fracture.

12. Methods of BMD measurement Common methods include Dual-energy x-ray absorptiometry (DXA) Quantitative ultrasonography (QUS), Other methods Conventional radiography, Quantitative CT (QCT), Single-photon absorptiometry (SPA), Dual-photon absorptiometry (DPA), MRI

13. 1 -Dual-energy x-ray absorptiometry (DXA)

14. DXA DXA is the “gold standard” and the most precise method for bone densitometry. Spine, femur , forearm

15. DXA R equires well-trained personnel C orrect patient positioning

16. DXA

17. DEXA scan: interpretation Some experts use Z-score of < -2 to view for secondary causes of osteoporosis; also can be used in young patients to assess for peak bone density 23

18. Advantages of DXA scan The most accurate and precise method available for the diagnosis of osteoporosis. It is one of the best methods to estimate the fracture risk. Non-invasive procedure Rapid, safe and very low radiation dose.

19. 2 -Qualitative ultrasound (QUS) Broadband ultrasound attenuation (BUA) in the calcaneus of th e dominant foot (which is related to BMD and structure ) as a potential indicator of hip fracture risk.   

20. Advantages of QUS it is radiation-free, cheap easy to use portable    and it has the possibility of predicting fracture risk.

21. Disadvantage of QUS Different B MD between left and right f ee t. In individuals with intellectual disabilities it c ould be difficult to determine which foot is dominant. Validity and sensitivity has not been established for all kinds of populations N ot validated as a screening method for osteoporosis.

22. Recent advances in QUS B oth lumbar spine and femoral neck.

23. 3 - C onventional R adiography Changes on plain radiographs can be seen only after approximately 30% of the bone is lost. Lesions less than 2cm may escape detection.

24. Radiographic manifestations of osteoporosis include the following: Increased radiolucency of bones Decreased number and increased thickness of trabeculae

25. Cortical thinning

26. Bone bars (reinforcement lines) Radiograph of the femur reveals trabecular bars (bone bars) perpendicular to the long axis of the bone, seen en face on the frontal view. BB are associated with lower BMD

27. Dowager’s hump

28. Note the overall reduction in the bone density and moderate kyphosis of the dorsal spine.

29. Vertebral Imaging Is indicated to rule out asymptomatic vertebral fractures

30. Vertebral fractures Compression deformities associated with protrusion of intervertebral disks and prominence of end plates .

31. Grading of vertebral fractures

32. Shape of fractured vertebral bodies in osteoporosis. A) Wedge shaped fracture of the vertebra. B) Concave fracture of the upper endplate of a thoracic vertebra . C) Biconcave vertebral fracture. Both endplates are fractured centrally. D) Crushed (black arrow) and wedge shaped (white arrow) vertebral bodies. Note Increased radiolucency of bones, Cortical thinning

33. 4-Single x-ray absorptiometry (SXA) O nly with the radius and calcaneus. The equipment is relatively compact and mobile, and scanning usually takes about 5 minutes with the forearm in a standard position.

34. 5 -Qualitative computerized tomography (QCT)

35. 6 -Single-photon absorptiometry (SPA) Single-energy source of gamma rays (iodine-125). It examines BMD of the radius and calcaneus.

36. 7 -Dual photon absorptiometry (DPA) 2 distinct photon energies, usually gadolinium-153. long scanning time, (1 hr) very expensive

37. Biochemical investigations in osteoporosis: Laboratory studies are used to establish baseline conditions before starting treatment or to exclude secondary causes of osteoporosis. Not used in diagnosis of osteoporosis.

38. Standard Laboratory Tests Calcium, P hosphate, Alkaline phosphatase, A lbumin, Kidney and liver functions. 25-OH Vitamin D 24-hour Urine calcium

39. Additional Laboratory Tests PTH TSH Serum protein electrophoresis (SPEP)/urine protein electrophoresis  ( UPEP) with immunofixation: These are used to identify multiple myeloma Testosterone In men with osteoporosis 24 hour urine cortisol In patients with cushingoid features and unexpected osteoporosis

40. 1- Markers of bone formation (osteoblast products ) : Bone-specific alkaline phosphatase (BSAP ) Osteocalcin (OC ) Carboxyterminal propeptide of type I collagen (PICP ) Aminoterminal propeptide of type I collagen (PINP) 2-Urinary markers of bone resorption (osteoclast products ): Hydroxyproline Deoxypyridinolines N- telopeptide of collagen cross-links ( NTx ) C- telopeptide of collagen cross-links ( CTx ) Tartrate-resistant acid phosphatase

41. Indications for biochemical markers Biochemical markers of bone turnover may: Predict extent of fracture risk reduction when repeated after 3-6 months of ttt Predict magnitude of BMD increases with FDA-approved therapies. Predict rapidity of bone loss Help determine adequacy of patient compliance and persistence with osteoporosis therapy

42. Before initiation of therapy, monitoring the response to therapy after 3-6 months (C-telopeptide of collagen cross-links (CTx) decreases) Aminoterminal propeptide of type I collagen (PINP) is preferred to monitor the effect of osteoanabolic drugs (teriparatide) which rapidly increases bone formation.

43. Quiz 1. Which of the following four BMD measurement sites is the best for assessing a patient’s risk of hip fracture? (A) Lumbar spine (B) Calcaneus (C) Femoral neck (D) Radius

44. Quiz The gold standard for diagnosis of osteoporosis is: Quantitative CT Dual-photon absorptiometry Quantitative ultrasonography Dual-energy x-ray absorptiometry