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Rickets and osteomalacia
- 2. Outline Introduction Clinical feature Etiology Pathology and pathophysiology Imaging 2
- 3. Introduction Zones of bone growth 1. Zone of resting cartilage contains normal, resting hyaline cartilage. 2. Zone of proliferating cartilage chondrocytes undergo rapid mitosis, leading to proliferation and form distinctive looking stacks. 3. Zone of maturation / hypertrophy – Chondrocytes enlarge and begin to secrete alkaline phosphatase which triggers calcification 3
- 4. Cont’d… 4. Zone of calcification – Chondrocytes die as they do not receive nutrition leaving cavities that will later become invaded by bone-forming cells. 5. Zone of ossification - Osteoprogenitor cells invade the area and differentiate into osteoblasts, which elaborate matrix that becomes calcified on the surface of calcified cartilage. 4
- 5. Normal bone growth 5
- 6. Normal X-ray of Lt Knee 6
- 7. Rickets The term is derived from ancient English term “wricken” which means “to bend”. It is the interruption of orderly development and mineralization of growth plate. Found in children prior to closure of growth plate The essential pathologic alteration involves deficiencies of vitamin D, calcium, or phosphate. 7
- 8. VITAMIN D AND RICKETS Vitamin D promotes differentiation of enterocytes and the intestinal absorption of calcium and phosphorus. This helps in bone mineralization. In conditions of hypocalcemia or hypophosphatemia, vitamin D stimulates bone resorption, thereby maintaining serum levels of calcium and phosphorus. vitamin D deficiency or resistance thus causes hypocalcemia and hypophosphatemia. 8
- 9. Cont’d… Hypocalcemia stimulates the release of PTH, which, through its actions on bone and kidney, partially corrects the hypocalcemia but enhances urinary phosphate excretion, leading to hypophosphatemia and osteomalacia. 9
- 10. Ca++ and phosphate metabolism 10
- 11. Vitamin D 11
- 12. Hx & P/E The classic vitamin D-deficient presentation develops 6-12 mths of age. Sx: muscle tetany & pain (commonest syptm.), irritability, weakness, delayed development, small stature, bone deformities and pain. Soft tissue swellings occur around the growth plates Multiple costochondral bumps at anterior rib cage (rachitic rosary). Enlargement of the wrists and costocartilage are most suggestive of the disease, with a specificity of 81% and 64%, respectively. Lab: ALP, Ca++ & phosphorus may be normal to slightly diminished. 12
- 13. Cf of Rickets 13
- 14. P/E 14
- 15. Ex The mineralization defects can be classified as Calcipenic (hypocalcemic) rickets caused by calcium deficiency or more commonly Vitamin D Phosphopenic (hypophosphatemic) rickets caused by phosphate deficiency & commonly caused by renal phosphate wasting Deficiency of vitamin D is usually more common than either isolated calcium or phosphorus deficiency 15
- 16. Causes 16
- 17. Pathology Decrease in the quantity of calcified osteoid and an increase in uncalcified osteoid (osteoid seams) generalized radiolucency The cartilage cells at the physis grow normally but fail to calcify and degenerate. the growth plate is occupied by enlarged masses of overgrown cartilage, (widening the region-- x-ray) Absent metaphyseal zone of provisional calcification (X-ray) The first sign of healing is restitution of this opaque metaphyseal line. 17
- 18. Terminology widening and irregularity of the growth plate ("fraying"). widening of the metaphyseal end of the bone ("splaying"). concavity of the metaphysis ("cupping") 18
- 19. Radiologic Features All bones will appear more radiolucent, with coarsened trabecular patterns. Widened growth plate (earliest radiographic mfn.)with irregular, frayed, and cupped metaphyseal margins ( paintbrush metaphyses) No distinct white line of the zone of provisional calcification. Epiphyses also appear frayed at the borders. 19
- 20. Cont’d… Bowing deformities, fractures, decreased bony length, scoliosis, and pseudo-fractures are other notable findings. Bulbous enlargement of the costochondral junctions (rachitic rosary) can be seen adjacent to cupped anterior rib ends, which can indent the pleural interface or even the thymic shadow. 20
- 22. 3 yr/F (A & B) 22
- 23. Cont’d… 23
- 24. Rickets 24
- 25. RICKETS: RACHITIC ROSARY 25
- 26. Other Imaging manifestations of Rickets MRI Though MRI is clearly unnecessary for the diagnosis of rickets, it is important that the typical features are not misinterpreted as other pathology. Findings include T2: wide physis of the secondary ossification center (SOC) absent zpc increased signal intensity of the physis 26
- 27. MRI 27
- 28. Radionuclide Radionuclide bone scanning is a useful aid in suspected cases. (preterm) It offers advantages over conventional radiology in terms of sensitivity, radiation dose and extent of examination. Unsuspected fractures of clinical or medicolegal significance may be detected. 28
- 29. DEXA Reduced aBMD, which are more pronounced in the diaphyseal than in the metaphyseal regions of the radius and ulna. CT data not available 29
- 30. Imaging differentials The differential for leg bowing Developmental or congenital bowing Blount disease osteogenesis imperfecta 30
- 33. The differential for widening of the growth plate Schmid-type metaphyseal chondrodysplasia Hypovitaminosis C (scurvy) Delayed maturation due to illness Endocrine disturbances Growth hormone excess Hyperparathyroidism Hypothyroidism 33
- 35. Scurvy 35
- 36. The differential for flaring of the metaphysis anaemia(s) fibrous dysplasia storage diseases chronic lead poisoning bone dysplasias 36
- 37. Mnemonic “RICKETS” Reaction of the periosteum (may occur) Indistinct cortex Coarse trabeculation Knees, wrists, and ankles affected predominantly Epiphyseal plates, widened and irregular Tremendous metaphysis (cupping, fraying, splaying) Spur (metaphyseal) 37
- 38. Osteomalacia Metabolic disorder that alters the quality of bone characterized by a lack of calcium salts being deposited in osteoid tissue. “soft bones.” s a condition that usually is overlooked and neglected B/C of wide spectrum of nonspecific clinical, radiographic, and biochemical manifestations 38
- 39. Causes 39
- 40. Clinical Features Often masked by its varied causes Asymptomatic Bone pain/tenderness Muscular weakness Lab: Inc. ALP, PTH, hydroxyproline Ca++ & P marginally diminished 40
- 41. Pathology Abnormal relative increase in uncalcified osteoid that coats the surfaces of trabeculae and linings of the Haversian canals (osteoid seams). Pseudo-fractures linear regions of unmineralized osteoid Occur bilaterally and symmetrically Either insufficiency fractures or vascular pulsations acting on the softened bone 41
- 42. Radiologic Features Decreased bone density may show characteristic “erased” or “fuzzy” type of demineralization. Coarse trabecular pattern Loss of cortical definition cortex reveals it to be thinner and altered in structure. 42
- 43. Cont’d… The only reliable sign for the diagnosis of osteomalacia is the presence of the Looser zone It is a radiolucency that runs perpendicular to the cortex of the bone and may have a sclerotic margin and be indistinguishable from the now frequently encountered stress fracture. 43
- 44. Pseudo-fractures linear radiolucencies that usually occur bilaterally and symmetrically The most common sites for them to occur are the femoral necks, pubic and ischial rami, ribs, and axillary margins of the scapulae. 44
- 45. Other causes of pseudo fractures Paget’s disease Fibrous dysplasia Rickets 45
- 46. Deformities In the pelvis, inferior displacement of the sacrum produces a triradiate shape to the pelvic canal Medial acetabular migration forms a protrusio acetabuli deformity Bowing of the femur and tibia also are seen Bellshaped thoracic cage 46
- 47. OM… 47
- 48. Cont’d… 48
- 49. Cont’d… 49 Kyphoscoliosis and increased endplate concavity
- 50. Articular manifestations (uncommon) Protrosio acetabuli Rheumatoid arthritis like changes Osteogenic synovitis Ankylosing spondylitis 50
- 52. om 52
- 53. CT Multidetector CT is well suited to demonstrate the intraspinal ossification, which is a rare, but recognized, complication of the enthesopathy associated with XLH osteomalacia 53
- 54. MRI MRI has been widely used for the evaluation of various disease processes, such as Pelvic insufficiency fractures and Oncogenic OM to detect the causative neoplasm Metastasis of the pelvic skeleton 54
- 55. Insufficiency fractures on MR The insufficiency fractures appeared as hypointense lines or fissures in both T1 & T2 Hyperintensity on T2WI adjacent to these hypointense fissures suggest acute insufficiency fracture 55
- 56. DEXA Low BMD in 70% of cases Bone scintigraphy May benefit to aid the location of pseudo fracture. 56
- 57. Reference 57
- 58. 58
Editor's Notes
- The matrix makes up about 30% of the bone and the other 70% is of salts that give strength to it. Matrix= collagen(90-95%) + other salts like CaPO
- Bone=matrix + cells Bone matrix consists of organic and inorganic components. Organic(Osteoid)= collagen type I (95%) + amorphous material, including glycosaminoglycans that are associated with proteins. Inorganic matter represents about 50% of the dry weight of bone matrix, composed of abundant calcium and phosphorus, as well as smaller amounts of bicarbonate, citrate, magnesium, potassium, and sodium. Calcium forms hydroxyapatite crystals with phosphorus but is also present in an amorphous form.
- 4. (zone of provisional calcification)
- Normal pattern of the left knee on a frontal plain radiograph (a) and a drawing (b). Routine radiograph of a healthy 9-year-old boy. The physis (arrows) appears as a radiolucent flat disc between the epiphysis and the metaphysis. The normal zone of provisional calcification (ZPC) (arrowheads) is a continuous, regular, thin (<1 mm thick) radiodense band.
- 25(OH)D also plays an important role in extraskeletal health. vitamin D deficiency may be associated with certain immunological conditions such as multiple sclerosis, type 1 diabetes, rheumatoid arthritis, inflammatory bowel disease, mood disorders, and cancers such as breast, prostate, and colon cancer. In adolescents, low serum vitamin D levels are associated with increased risk of hypertension, hyperglycemia, metabolic syndrome, and higher risk of upper respiratory infections. This chapter focuses on the skeletal manifestations of vitamin D deficiency
- Diagram of the calcium homeostasis pathway. Ingested calcium is absorbed in the gastrointestinal tract, and vitamin D is either absorbed in the gastrointestinal tract or generated from 7-de-hydrocholesterol through exposure to UV light (UVB). Vitamin D is further processed in the liver and kidney, where it is converted to its fully active form, which promotes calcium absorption in the gut. Parathyroid hormone acts on the bones and the kidneys to increase serum calcium levels, and high serum calcium levels in turn suppress parathyroid hormone secretion. But it also promotes urinary phosphate excretion resulting hypophosphatemia. Parathyroid hormone, calcium, and phosphorous also modulate vitamin D metabolism in the kidney (21). 25(OH)D= 25-hydroxy-vitamin D, 1,25-(OH)2D= 1,25-dihydroxy-vitamin D.
- Soft tissue swellings occur around the growth plates owing to hypertrophied cartilage.
- As in osteomalacia, histopathologic examination of rachitic bone demonstrates a decrease in the quantity of calcified osteoid and an increase in uncalcified osteoid (osteoid seams).
- (a)Anteroposterior radio-graph of the skull shows a partially patent frontal suture (arrow). (b)Posteroanterior radiograph of the chest shows wide and rounded anterior rib ends (circles). This finding is often called a “rachitic rosary” because the chain of rounded rib ends resembles rosary beads at physical examination. C. Anteroposterior radiograph of both lower extremities obtained 2 years later than a–d shows diffuse osteopenia, bowing of the tibiae and fibulae, flared metaphyses, and widening of the growth plates with sclerosis and irregularity on the metaphyseal side. Transverse sclerotic metaphyseal bands (arrows) parallel to the growth plate reflect periods of intermittent adequate mineralization followed by poor mineralization
- A. Posteroanterior radiograph of both hands shows diffuse osteopenia, age-indeterminate fractures of several metacarpals (solid arrows), and cupped fragmented frayed metaphyses of the distal radii and ulnae (ovals). A peripheral rim of bone along the metaphysis (dashed arrow) occurs by membranous ossification. B. Anteroposterior radiograph of both knees shows a fracture of the patient’s right distal femur (black arrow), as well as age-indeterminate fractures of her right tibia and both fibulae (dashed white arrows). The metaphyses are fragmented, frayed, and fractured (solid white arrow)
- Radiographs of the knee of a 3.6-year-old girl with hypophosphatemia depict severe fraying of the metaphysis. Radiograph in a 4-year-old girl with rickets depicts bowing of the legs caused by loading. rachitic rosary
- Observe the opaque, bulbous indentations of the lung adjacent to the enlarged costochondral junctions (arrows).
- 1: sagittal T2-weighted image with fat suppression(TR 4000/TE 110) of the femur shows a healing pathologic fracturewith periosteal reaction and marrow edema (curved arrow). Additionally, widening and increased T2 signal are seen in the main physis (large straight arrow) and the physis of the SOC (small straight arrow) 2: coronal T2-weighted image with fat suppression(TR 3200/TE 102) of the left hip reveals widening and increased signal of the physis of the SOC (open arrow) as well as loss of the zpc. There is no evidence of slippage of the femoral head
- aBMD—area bone mineral density
- B. Bilateral varus deformity (bowing). Medial spur from the tibial metaphysis evident on the right side Disturbed defective growth of the medial proximal tibial epiphysis.Irregularities of the physis on both sides. Dfn: local disturbance of growth of the medial aspect of the proximal tibial metaphysis and/or epiphysis that results in tibia vara. The condition is commonly bilateral.
- All bones are over-transparent suggesting osteopenia. Long bones are deformed due to muscles growth, which osteopenia cannot correct. Multiples fractures of different ages are seen Dfn: a heterogeneous group of congenital, non-sex-linked, genetic disorders of collagen type I production, involving connective tissues and bones. Radiographic findings: head, neck and spine basilar invagination wormian bones kyphoscoliosis vertebral compression fractures codfish vertebrae platyspondyly chest pectus excavatum or carinatum pelvis acetabular protrusio coxa vara general severe osteoporosis deformed, gracile (over-tubulated) bones cortical thinning hyperplastic callus formation popcorn calcification: the metaphyses and epiphyses exhibit numerous scalloped radiolucent areas with sclerotic margins 1 zebra stripe sign: cyclic bisphosphonate treatment produces sclerotic growth recovery lines in the long bones formation of pseudarthrosis at sites of healing fractures
- AP radiograph of knees. Note irregularity, sclerosis and widening of the metaphyses with normal epiphyses
- White line adjacent to epiphyseal plate. Wimberger's ring sign. Trummerfeld zone. Pelken spurs. Subperiosteal haemorrhage. Osteoporosis. Wimberger sign: presence of a sclerotic rim around epiphysis White line of frankel: dense zone of provisional calcification at the growing metaphysis Trumerfeld zone: a lucent zone below white line due to lack of mineralisation Pelkan spur:as the area is prone to fractures manifesting at cortical margin Osteoporosis Subperiosteal haemorrhage.
- Loss of cortical definition: Close examination of the cortex reveals it to be thinner and altered in structure. Usually, the endosteal surface is blurred and indistinct. Coarsened Trabecular Pattern. A decrease in the overall number of bony trabeculae within all bones enhances the contrast of those remaining. As a result, the texture of the spongiosa may appear coarse and mottled. Fig: The trabecular pattern is fuzzy, coarse, and has a ground-glass appearance
- Other name for Looser zone are: pseudofractures Increment fractures Milkman’s syndrome Umbau zonen
- Pseudo-fractures occur in other bone-softening disorders, including Paget’s disease, fibrous dysplasia, rickets, and hyperphosphatasia. Paget’s disease extensive bone remodeling expanded bone with coarse trabecular pattern. Fibrous dysplasia localised defect in osteoblastic differentiation and maturation, with the replacement of normal bone with large fibrous stroma and islands of immature woven bone expansile ground glass appearing/ lytic bone lesion Hyperphosphatasia
- OSTEOMALACIA: PSEUDO-FRACTURES. AP Pelvis. Note the true subtrochanteric fracture(arrowhead) and the pseudofractures (arrows) of the pubes. B. AP Pubis. Note that the bulbous appearance is caused by callus formation at the pseudo-fracture site (arrows). Additional pseudo-fractures can be seen through the body of the pubis (arrowheads)
- C and D. Scapular Axillary Borders. E. PA Forearm. Note the pseudofractures in the radius and ulna (arrows) These defects are recognized by their bilateral symmetry and perpendicular orientation to the cortex
- OSTEOMALACIA: DEFORMITY. A. Lateral Thoracic Spine. Observe the increased biconcave endplate contours. The trabeculae are coarsened. B. Acute Fracture Lateral Elbow. Note that after trivial trauma a fracture has occurred through the distal humerus. Note the pseudofracture in the proximal radius
- Protrusion of acetabulum in case of osteomalacia Dfn: Acetabular protrusio (also known as acetabular protrusion) is intrapelvic displacement of the acetabulum and femoral head, so that the femoral head projects medial to the ischioilial line.
- Triradiate appearance of the pelvis with bilateral acetabula protrusio. Osteopenic texture of the examined bones with coarse trabeculae. Right superior and inferior pubic rami Looser's zones. Subchondral bone absorption of acroiliac joints (more on the right). Red arrows: represent stress fractures (looser's zones) Yellow arrows: represent subchondral bony resorption at the sacroiliac joint.
- X-linked hypophosphatemia (XLH), also called X-linked dominant hypophosphatemic rickets, X-linked vitamin d-resistant rickets, is an X-linked dominant form of rickets (or osteomalacia) that differs from most cases of rickets in that ingestion of vitamin D is relatively ineffective
- Figure 2 53-year-old female woman who presented with chronic pelvic pain and history of decreased sun exposure (she was wearing long garments and veils). (a) Pelvic radiograph reveals insufficiency fractures at the superior and inferior pubic rami (white arrowheads). No pathological lesion was seen in the iliac and sacral bones. (b) Coronal T2-weighted MRI shows insufficiency fractures as hypointense fissures (arrows) without pathological signal intensity (sequel or healed fractures) at the pubic rami. (c) Coronal T1 and (d) T2-weighted MRI demonstrate a hypointense fissure line (white arrow) with pathological signal intensity (white arrowhead) at the right iliac bone (active type of insufficiency fracture). (e) Second-year follow-up coronal STIR MRI depicts the hypointense fissure and disappearance of the pathological signal intensity (white arrowhead). (f) Follow-up MR coronal STIR image also depicts a new hyperintense lesion at the left ramus pubis (arrowhead). Note the sequel or healed fracture lines at the pubic rami on this image (white arrows).
- A whole-body 99m Tc- methylene diphosphonate bone scintigraphy showed increased uptake in the chest, both femoral heads, sacrum, left knee and left ankle, consistent with multiple pseudo-fractures