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Metabolic Bone disease: Things I didn’t understand as a Medical student/ FY1/ SHO/ SPR. James Bateman Arthritis Research UK Educational Research Fellow. Aims and Objectives. Aims Understand the definition and spectrum of metabolic bone diseases Objectives - PowerPoint PPT Presentation
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Metabolic Bone disease:
Things I didn’t understand as a Medical student/ FY1/ SHO/ SPR
James Bateman
Arthritis Research UK Educational Research Fellow
Aims and Objectives
• Aims– Understand the definition and spectrum of
metabolic bone diseases
• Objectives– demonstrate understanding of epidemiology,
aetiology, clinical features and management of osteoporosis, osteomalacia, Paget’s disease and renal osteodystrophy
Case 1
• 72 year old lady • Acute onset severe thoracic pain• Keeping her awake at night• Radiates around ribs• No history of trauma• PMH – COPD• DH - Inhalers
• What other questions would you ask?
Case 1 - contd
• On examination – – Frail lady– Apyrexial– Thoracic kyphosis– Tender over spinous processes T7/8– No neurological deficit
– differential diagnosis?
Diff. Diagnosis of Back Pain
• Simple mechanical eg ligamentous strain• Degenerative disease with/without neural, cord
or canal compromise• Metabolic – osteoporosis, Pagets • Inflammatory – Ankylosing spondylitis• Infective – bacterial and TB• Neoplastic• Others, (trauma,congenital)• Visceral
Case 1
• Investigations
• HB 12.9, WCC 9.0, Plts 245
• Na 139, K 4.4, U 7.3, Cr 96
• Alk Phos 297, ALT 32, Bil 13, Ca 2.41
• CRP 8
Osteoporosis
Reduction in bone mass leading to increase risk of fracture
Ratio of mineralised bone: “matrix is normal”
Imbalance of bone remodelling
• Risk factors for osteoporosis?
• Measurement and definition of OP?
T scores
• Typical OP # ?
OP fractures
250,000 # / yr in UK
• Treatment for OP ?
Osteoporosis
• Lifestyle factors– Falls prevention– Hip protectors
• Ca and Vit D
• Bisphosphonates
• Strontium
• SERMs
• Teriparatide- PTH
Preventing steroid induced osteoporosis
• All: lifestyle advise, calcium and vit D
• Age <65 DEXA- if T score -1.0 or less then alendronate
• Age >65 alendronate
NICE guidance
• http://guidance.nice.org.uk/TA87/?c=91524
• www.sheffield.ac.uk/FRAX/tool
Case 2
• 33 year old Asian lady• Presents with 3 /12 history of generalised
bony pain• PMH – depression• DH – sertraline
• O/E – generalised bony tenderness• Joints – normal ROM, no inflammation
Investigations
• Hb 12.9 (11.5-16.5) Calcium 2.18 (2.2-2.6)
• WCC 4.7 (4.9-11.0) Phosphate 0.79 (0.85-1.45)
• Plt 253 (150-400) Albumin 39 (35-50)• ESR 12 Alk Phos 172 (25-96)• Clotting Normal Total protein 72 (60-80)• Urea 4.2 (3.0-6.5) LFTs normal• Creat 85 (35-120)
• Diagnosis?
Osteomalacia
• Rickets of adulthood• Deficiency OR resistance to Vit D OR Phosphate
handling problem• Defective mineralization of bone• Proximal myopathy, Bony pain, malaise
– Deformities much less common than with rickets
• AP raised, Ca and Vit D low or normal• PO4 low or normal
What I didn’t understand as a medical student…
• Bone remodelling is a continuous process with uptake and laying down of new matrix (osteoid) and its mineralisation (Ca&PO4)
• In osteomalacia: the osteoid is normal (the matrix laid down by the osteoblasts)
• Normally calcium and phosphate are then ladi down some 15 dyas later, and converted to hydroxyapatite)
What I didn’t understand as a medical student…
• You need enough phosphate to mineralise bone:
• PTH stops you the renal re-absorbtion of phosphate
• So that’s why osteomalacia happens with vitamin D deficiency
Causes?
Causes of osteomalacia/rickets
• Reduced availability of Vit D
– Diet: oily fish, eggs, breakfast cereals
– Elderly individuals with minimal sun exposure
– Dark skin, skin covering when outside
– Kidney failure
– malabsorption
• malabsorption– Coeliac– Intestinal bypass– Gastrectomy– Chronic pancreatitis– Pbc
• Epilepsy: phenytoin, phenobarbitones
• Defective metabolism of Vitamin D– Chronic renal failure, Vit D dependent rickets,– Liver failure, anticonvulsants
• Receptor Defects
• Altered phosphate homeostasis– Malabsorption, RTA, hypophosphatasia (rare,
low levels of alk phos)
Loosers zones
Treatment
• Vitamin D –usually oral- HIGH DOSE
• Calcium supplements
Case 3
• 62 year old lady referred with generalised muscular pain
• PMH – hypertension• DH – bendrofluazide• Examination – largely unremarkable• Routine bloods all normal except Calcium of
2.95• She has come back to clinic for results• What would you do now?
Symptoms of hypercalcaemia
• Stones,
• Bones,
• Moans,
• Psychic Groans
An approach to hypercalcaemia
• Stones, Renal colic
• Bones, Joint, bone, muscle pain, Muscle weakness
• Moans, Constipation Abdominal pains
• Psychic Groans Depression, confusion, altered mental state, Fatigue, lethargy
• Dehydration, polyuria
Causes of Hypercalcaemia?
Causes of Hypercalcaemia
• Malignancy
• Hyperparathyroidism – primary or tertiary
• Increased intake
• Myeloma
• Sarcoid
• Adrenal failure
Treatment of acute hypercalcaemia?
Treatment of acute hypercalcaemia
• Hydration, IV if Ca very high
• Bisphosphonates
• Treat cause
Hyperparathyroidism
• Primary hyperparathyroidism:– Often an incidental finding
– May be part of MEN I, MEN II
• Secondary hyperparathyroidism– Compensates for chronic low Ca eg. Renal failure or malabsorption
– [Ca2+] and [PO42-] normal PTH high
• Tertiary hyperparathyroidism– Hyperplasia in longstanding secondary disease
Multiple endocrine neoplasia
• Aut dom
• MEN 1 parathyroid tumours, ant pituitary, pancreas
• MEN 2A thyroid tumour, phaeochromocytomas, parathyroid hyperplasia
• MEN 2B thyroid tumours and phaeos
Hypoparathyroidism
Causes
• Destruction of gland- surgical (thyroidectomy- may be transient)
• Autoimmune- polyglandular autoimmune glandular syndrome
• Irradiation or infiltration (cancer, wilsons)
• Abnormal gland development
Case 4
This 73 year old lady was referred from her GP to ENT with deafness.
They asked her to see the rheumatologist
Why?
Paget’s Disease
• Disease of bone remodeling
• Accelerated bone resorption and formation
• Disorganised mosaic pattern bone with increased vascularity and fibrosis
• Cause unknown
– paramyxovirus, canine distemper
– Genetics- susceptibility loci
• More common in caucasian
• M:F ratio 3:2 10% in over 70’s
Paget’s Disease: clinical manifestations
• Bone pain
• Joint pain
• Deformity
• Spontaneous fractures
Pagets Disease: complications
• Fractures
• Deafness
• Nerve entrapment
• Spinal stenosis
• Cardiac failure
• Osteogenic sarcoma
• Hypercalcaemia (only if immobilized)
Paget’s Disease: investigations
• Raised serum alk phos
• (Urinary hydroxyproline, pyridinoline cross-links)
• Radiology:
Normal
• Radiology
– cortical thickening
– osteolytic, osteosclerotic and mixed lesions
– osteoporosis circumscripta
– bone scan
Paget’s Treatment
• Bisphosphonates– calcitonin
• Indicated if – Complications– Pain– Deformity– AP 2-3X Upper limit– Skull disease
Questions?