Post on 24-Feb-2016
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Prof. Mamoun KremliAlMaarefa College
Metabolic Bone Disorders
ObjectivesBone as an active tissue
Calcium is an important mineral
Calcium metaboism – normal control
DiseasesOsteoporosisRickets and OsteomalaciaHyperparathyroidismScurvy
Functions of bone tissueMechanical:
Support & protect soft tissueLoad transmissionMediate movement
Mineral reservoirLargest reservoir of CaRegulation of Ca
Basic Anatomy of Bone
http://classes.midlandstech.edu/
Bone componentsA: Matrix:
Organic: (40% of dry weight)Collagen fibersCells
Inorganic (Minerals): (60%)Ca hydroxyapetite, Ca phosphateOthers
B: Cells:Osteoblasts, osteoclasts, osteocytes, others
Bone cellsOsteoblasts
Osteoclasts
Osteocytes
Osteone:
a unit, not a cell
Bone is activeContinuous activity and flow
Structure and composition changing all the time
Regulations by regulating cellular activity:Osteoclasts & Osteoblasts
Cellular Activity
Modulation of Bone
Structure & Composition
Changes in mineral ion
concentrations
Hormones & Local Factors
Bone growth & remodellingGrowth:
Epiphyseal: Endochondral ossificationOn surface: Oppositional ossification
In Adults:Remodelling of existing bone (no growth)
Annually: 4% of cortical and 25% of cancellous“old bone” continuously replaced by “new bone”
Initially: formation slightly exceeds resorptionLater: resorption exceeds formation
Bone mass steadily declines
Age related bone changesChildhood – adolescence: Growth ( size & change shape)
Adolescence – 35 (40) years: Bones get heavier and stronger Annual bone mass gain: 3%
35 (40) – 50 years: Slow loss of bone mass annually: Men: 0.3% Women:
0.5% to menopause, then 3% for 10 years - (Why?) (↑ osteoclastic activity by ↓ hormones)
65 years – onwards: Loss of mass slows gradually to 0.5% (↓osteoblastic activity)
Body CalciumMost of Ca in body is present in bone
Release of Ca from bone is a slow process
Serum calcium is essential for cell function, nerve conduction, and muscle contractionNormal level: 8.8-10.4 mg/dl (2.2-2.6 mmol/L)S. levels have to be controlled quickly
Intestinal absorptionRenal reabsorption
Causes of Calcium absorption
intake of phosphates (as in soft drinks)
intake of oxalates (as in tea and coffee)
Drugs: corticosteroids
Intestinal malabsorption syndromes
Players in Ca regulationVit. D is the general crude regulator
Target organs:Small intestinesBones
PTH is the sensitive fine regulatorTarget organs:
Kidneys (v quick)Bones (slow)(indirectly): small intestine
Players in Ca regulationCacitonin: C cells of Thyroid
Opposite PTH on bone and kidneys
Oestrogen:Protects bone from PTH
Corticosteroids:Bad to bone
Local – BMP (Bone Morphogenic Proteins)
Mechanical stress:Strengthens bone
Hormonal regulation of Ca met.
Laboratory investigationsX-rays
Bone mineral density (BMD)DEXA scans: Dual Energy X0ray Absorptiometry
Biochemical tests:Serum Ca, PhosphateSerum Alkalin Phosphatase
Osteoclastic activity, measures bone turnover rateVit. D levelsUrine Ca and Phosphate excretionRenal profileLiver function test
Common DiseasesOsteoporosis
Rickets
Osteomalacia
Hyperparathyroidism (osteitis fibrosa)
OsteoporosisReduction of bone mass
Bone minerals and matrix both reducedMatrix present is normally mineralized
Types:Generalized:
systemic diseaseLocalized:
disuse (e.g. in cast)
http://drcecilia.ca/
OsteoporosisMore in women
Post menopausalOestrogen withdrawal
Increased with:cigarette smokingwhen start menopause with weak bones
In men:15 years later
In elderly, may be associated with osteomalacia
Osteoporosis – clinical featuresWeak bones: easily fractures:
Vertebral compression fractures Backache, kyphosis
Colle’s fractureNeck of femurProximal humerus
Orthopedic Radiology, A Greenspan. lippincott
Osteoporosis – clinical featuresWeak bones: easily fractures:
Vertebral compression fractures Backache, kyphosis
Colle’s fractureNeck of femurProximal humerus
http://library.med.utah.edu
Orthopedic Radiology, A Greenspan. lippincottwww.rcuv.org/tag/health
Osteoporosis – clinical featuresWeak bones: easily fractures:
Vertebral compression fractures Backache, kyphosis
Colle’s fractureNeck of femurProximal humerus
http://library.med.utah.edu
Orthopedic Radiology, A Greenspan. lippincottApley’s System of Prthop & Fractures
Osteoporosis – clinical featuresWeak bones: easily fractures:
Vertebral compression fractures Backache, kyphosis
Colle’s fractureNeck of femurProximal humerus
Loss of cortical thicknessseen on X-rays
http://library.med.utah.edu
Orthopedic Radiology, A Greenspan. lippincottApley’s System of Prthop & Fractures
Risk Factors for postmenopausal osteoporosis
Caucasian (white) or Asiatic ethnicity
F.H. of osteoporosis
H.O. anorexia nervosa or amenorrhea
Low peak bone mass in third decade
Early onset menopause
Very slim built
Oophorectomy and early hysterectomy
Nutritional deficiency
Chronic lack of exercise
Osteoporosis - PreventionGood Ca and Vit. D intake
Good physical activity
Exposure to sun
No smoking
No alcohol
http://dietitians-online.blogspot.com
Osteoporosis - PreventionIf BMD low:
Hormone replacement therapy (oestrogen):Effective earlyFor initial five yearsProblems:
Dysfunctional uterine bleedingRisk of uterine and breast cancer – on long use
Osteoporosis - treatmentTreat the fractures
Maintain good Ca and Vit D intakeMay be associated with osteomalacia
Maintain good physical activity
Trying to reduce rate of further bone lossHormone replacement therapyBisphosphonates
Rickets & Osteomalacia
Rickets & OsteomalaciaSame disease: (children / adults)
Inadequate absorption and/or utilization of Ca
Common causes:Lack of Vit. DSever Ca deficiencyHypophosphatemia
Results in loss of mineralization of bone
Rickets - pathologyMatrix forms, not calcified
In growing physisWidened physis (epiphyseal growth plate)Cupping of metaphyseal end (weak new bone)
In all boneOsteopenia, Thin cortex, Deformity
Harrisons sulcus, frontal bossing
In sever cases: hypocalcaemia:Tetany, convulsions, failure to thrive
Rickets – clinical pictureEnlarged ends of long bones
Wrists, knees
Rickety rosary:costo-chondral junctions
Harrisons sulcus
Frontal bossing
Bowing of legs:Localized – distal tibiae
In sever cases: tetany, convulsions
Orthopedic Radiology, A Greenspan. lippincott
Rickets – clinical pictureEnlarged ends of long bones
Wrists, knees
Rickety rosary:costo-chondral junctions
Harrisons sulcus
Frontal bossing
Bowing of legs:Localized – distal tibiae
In sever cases: tetany, convulsions
http://www.magazine.ayurvediccure.com/
www.thachers.org
Rickets – clinical pictureEnlarged ends of long bones
Wrists, knees
Rickety rosary:costo-chondral junctions
Harrisons sulcus
Frontal bossing
Bowing of legs:Localized – distal tibiae
In sever cases: tetany, convulsions
www.thachers.org
Rickets – clinical pictureEnlarged ends of long bones
Wrists, knees
Rickety rosary:costo-chondral junctions
Harrisons sulcus
Frontal bossing
Bowing of legs:Localized – distal tibiae
In sever cases: tetany, convulsions
www.thachers.org
Rickets – clinical pictureEnlarged ends of long bones
Wrists, knees
Rickety rosary:costo-chondral junctions
Harrisons sulcus
Frontal bossing
Bowing of legs:Localized – distal tibiae
In sever cases: tetany, convulsions
Rickets – clinical pictureEnlarged ends of long bones
Wrists, knees
Rickety rosary:costo-chondral junctions
Harrisons sulcus
Frontal bossing
Bowing of legs:Localized – distal tibiae
In sever cases: tetany, convulsions
N Engl J Med 2009
Rickets – X-raysWidened physis (epiphyseal growth plate)
metaphyseal end of physisCupping of (weak new bone)Irregular
Deformed bones
Orthopedic Radiology, A Greenspan. lippincott
Rickets – X-rays
Orthopedic Radiology, A Greenspan. lippincott
Rickets – X-rays
Orthopedic Radiology, A Greenspan. lippincott
Rickets – lab resultsSerum Ca:
slightly low /or normal
Serum Phsphate:slightly low /or normal
Alk Phosphatase:High – a lot of bone turnover
Vit. D level: low
PTH level: Increased – scondary effect – to keep s. Ca level
Urinary Ca: V. low
Rickets - treatmentVit. D and Calcium
Most deformities correct graduallySever deformities might need surgical correction
Hopophsphataemic ricketsVit. D resistant rickets
Familial, X-linkedImpaired renal tubular reabsorption of phosphate
Lab. Results:Serum Phosphate: lowUrinary phosphate: high
Treatment:High dose Vit. DPhosphate
OsteomalaciaCaused by defective Vit. D:
Deficiency – lack of sun exposureIntestinal malabsorptionDefective formation of active Vit. D:
Liver or Renal disease
Clinical featuresBone aches – backache, hip pain
Compressed vertebral fractureInsufficiency fractures of femur / tibia
Orthopedic Radiology, A Greenspan. lippincott
Osteomalacia – X-raysWeak osteopaenic bone
Biconcave vertebrae & compression fractures
Trefoil pelvis – acetabular protrusion
Typically: Looser’s zones:Poorly healing stress fractures
Neck of scapulaNeck of femurPubic bones
Apley’s System of Prthop & Fractures
Osteomalacia – X-raysWeak osteopaenic bone
Biconcave vertebrae & compression fractures
Trefoil pelvis – acetabular protrusion
Typically: Looser’s zones:Poorly healing stress fractures
Neck of scapulaNeck of femurPubic bones
Apley’s System of Prthop & Fractures
Osteomalacia – X-raysWeak osteopaenic bone
Biconcave vertebrae & compression fractures
Trefoil pelvis – acetabular protrusion
Typically: Looser’s zones:Poorly healing stress fractures
Neck of scapulaNeck of femurPubic bones
Orthopedic Radiology, A Greenspan. lippincott
Osteomalacia – X-raysWeak osteopaenic bone
Biconcave vertebrae & compression fractures
Trefoil pelvis – acetabular protrusion
Typically: Looser’s zones:Poorly healing stress fractures
Neck of scapulaNeck of femurPubic bones
Apley’s System of Prthop & Fractures
http://www.omjournal.org
Osteomalacia – X-raysLooser’s zone
Orthopedic Radiology, A Greenspan. lippincott
HyperparathyroidismPrimary:
Parathyroid adenoma / hyperplasis
Secondary:Hyperplasia due to hypocalcaemia
Tertiary:Autonomous activity after secondary hyperplasis
HyperparathyroidismEffect of PTH
Target organs:KidneysBonesIntestines (indirect)
Bone weakens, resorptionIncreased serum Ca
Orthopedic Radiology, A Greenspan. lippincott
HyperparathyroidismBones
RarefactionSubperiosteal resorption (middle phalanges)Reorption of lateral end clavicleBrown tumors
StonesKidney stones and nephroclacinosis
MoansAbdominal pain, renal pain
GroansPschological depression, stress
Hyperparathyroidism – x-raysBones
RarefactionBone resorption
Subperiosteal resotptionmiddle phalangesTibial shaft
lateral end clavicleBrown tumorsSkull: salt & pepper
Soft tissue calcification
www.eurorad.org
Hyperparathyroidism – x-raysBones
RarefactionBone resorption
Subperiosteal resotptionmiddle phalangesTibial shaft
lateral end clavicleBrown tumorsSkull: salt & pepper
Soft tissue calcificationOrthopedic Radiology, A Greenspan. lippincott
Hyperparathyroidism – x-raysSubperiosteal bone resorption
Orthopedic Radiology, A Greenspan. lippincott
Hyperparathyroidism – x-raysBones
RarefactionBone resorption
Subperiosteal resotptionmiddle phalangesTibial shaft
lateral end clavicleBrown tumorsSkull: salt & pepper
Soft tissue calcification
Orthopedic Radiology, A Greenspan. lippincott
Hyperparathyroidism – x-raysSubperiosteal bone resorption
Orthopedic Radiology, A Greenspan. lippincott
Hyperparathyroidism – x-raysBones
RarefactionBone resorption
Subperiosteal resotptionmiddle phalangesTibial shaft
lateral end clavicleBrown tumorsSkull: salt & pepper
Soft tissue calcification Orthopedic Radiology, A Greenspan. lippincott
Hyperparathyroidism – x-raysBones
RarefactionBone resorption
Subperiosteal resotptionmiddle phalangesTibial shaft
lateral end clavicleBrown tumorsSkull: salt & pepper
Soft tissue calcification
Orthopedic Radiology, A Greenspan. lippincott
Hyperparathyroidism – x-raysBones
RarefactionBone resorption
Subperiosteal resotptionmiddle phalangesTibial shaft
lateral end clavicleBrown tumorsSkull: salt & pepper
Soft tissue calcification
http://www.radpod.org/2008
Hyperparathyroidism – x-raysBones
RarefactionBone resorption
Subperiosteal resotptionmiddle phalangesTibial shaft
lateral end clavicleBrown tumorsSkull: salt & pepper
Soft tissue calcificationOrthopedic Radiology, A Greenspan.
lippincott
Hyperparathyroidism – x-raysBones
RarefactionBone resorption
Subperiosteal resotptionmiddle phalangesTibial shaft
lateral end clavicleBrown tumorsSkull: salt & pepper
Soft tissue calcificationOrthopedic Radiology, A Greenspan. lippincott
Hyperparathyroidism - treatment
Hydration
Reduced calcium intake
If adenoma:Surgical removalBeware of the “hungry bone” syndrome post
operatively – severe hypocalcaemia (why?)
Scurvy – Vit. C deficiencyFirst discovered in sailors
Failure of collagen fibers formation
Weak osteoid matrix
Clinical picture:Child irritable, anemiaBleeding gumsPain and swellings at ends of long bones
Scurvy – Vit. C deficiencyX-rays:
Osteopaenia – more at mataphysisSub-periosteal bleeding
Periosseous calcificationRing epiphysisSclerosis at juxtaepiphyseal metphysis
Treatment:Vit C (large doses)
Scurvy – Vit. C deficiency
Orthopedic Radiology, A Greenspan. lippincott
Scurvy – Vit. C deficiency
Orthopedic Radiology, A Greenspan. lippincott
Scurvy – Vit. C deficiencyX-rays:
Osteopaenia – more at mataphysisSub-periosteal bleeding
Periosseous calcificationRing epiphysisSclerosis at juxtaepiphyseal metphysis
Treatment:Vit C (large doses)
SummaryBone is an active tissue
Continuous absorption and rebuilding
Calcium is an important mineral
Calcium control
DiseasesOsteoporosisRickets and OsteomalaciaHyperparathyroidismScurvy