Metabolic Bone Disease Flashcards
What are 5 metabolic bone diseases?
Pagets disease Renal Osteodystrophy Osteoporosis Osteomalacia/rickets Hyperparathyroidism (primary)Pagets disease Renal Osteodystrophy Osteoporosis Osteomalacia/rickets Hyperparathyroidism (primary)Pagets disease Renal Osteodystrophy Osteoporosis Osteomalacia/rickets Hyperparathyroidism (primary)
What is the composition of bone?
80% compact/cortical
20 % anellous/spongy80% compact/cortical
20 % anellous/spongy80% compact/cortical
20 % anellous/spongy
What is cancellous/spongy bone important for?
Calcium metabolism, found especially in the vertebra and pelvis
What disease features are seen in osteoporosis?
Decreased bone mass
DEXA scan: Tscore >2.5 SD below normal (1-2.5 = osteopaenia)Decreased bone mass
DEXA scan: Tscore >2.5 SD below normal (1-2.5 = osteopaenia)Decreased bone mass
DEXA scan: Tscore >2.5 SD below normal (1-2.5 = osteopaenia)
What disease features are seen in Osteomalacia/rickets?
Decreased bone mineralization
What disease features are seen in Primary hyperparathyroidism?
Bone changes of osteitis fibrosa cystica
What disease features are seen in Pagets disease?
Both lytic and lerotic lesions
What can cause osteoporosis
Mostly age related
Post-menopause in women
Secondary to systemic disease/drugsMostly age related
Post-menopause in women
Secondary to systemic disease/drugsMostly age related
Post-menopause in women
Secondary to systemic disease/drugs
What can cause rickets?
Decreased Vit D
Decreased dietray Vit D,
decreased sunlight,
malabsoprtion of Vit D (GI causes)
genetic causesDecreased Vit D
Decreased dietray Vit D,
decreased sunlight,
malabsoprtion of Vit D (GI causes)
genetic causesDecreased Vit D
Decreased dietray Vit D,
decreased sunlight,
malabsoprtion of Vit D (GI causes)
genetic causes
Define pagets disease:
Paget’s disease chronically disrupts the normal cycle of bone renewal and repair, causing bones to become weakened and enlarged/deformed
What is the aetiology of primary hyperparathyroidism?
Excess PTH production –> increased calcium reabsorption and increased phosphate excretion
What can cause primary hyperparathyroidism?
Parathyroid adenoma MEN Carcinoma HyperplasiaParathyroid adenoma MEN Carcinoma HyperplasiaParathyroid adenoma MEN Carcinoma Hyperplasia
Define Renal Osteodystrophy
a bone disease that occurs when your kidneys fail to maintain proper levels of calcium and phosphorus in the blood. It’s common in people with CKD and affects most dialysis patients.
What are the symptoms of Pagets disease?
Bone pain Microfractures Nerve compression Skull changes (increased head size) Deafness High output cardiac failureBone pain Microfractures Nerve compression Skull changes (increased head size) Deafness High output cardiac failureBone pain Microfractures Nerve compression Skull changes (increased head size) Deafness High output cardiac failure
What are the symptoms of hyperparathyroidism?
Hypercalcaemia: Moans, Stones, Bones, Groans
Depression/confusion Renal stones Bone pain and fractures Constipation Pancreatitis POlyuria PolydipsiaHypercalcaemia: Moans, Stones, Bones, Groans
Depression/confusion Renal stones Bone pain and fractures Constipation Pancreatitis POlyuria PolydipsiaHypercalcaemia: Moans, Stones, Bones, Groans
Depression/confusion Renal stones Bone pain and fractures Constipation Pancreatitis POlyuria Polydipsia
What are symptoms of Hypercalcaemia?
Moans Stones Bones GroansMoans Stones Bones GroansMoans Stones Bones Groans
What are the symptoms of osteoporosis?
Low impact fractures (hip - NOF, vertebrae, wrists - colles’)
Back painLow impact fractures (hip - NOF, vertebrae, wrists - colles’)
Back pain
What is the difference between rickets and osteomalacia?
Osteomalacia (adults) and rickets (children) are caused by inadequate mineralisation of bone matrix. Vitamin D deficiency causes low calcium and phosphate, which lead to secondary hyperparathyroidism. Osteomalacia results from a loss of skeletal mass caused by inadequate mineralisation of the normal osteoid tissue after the closure of the growth plates. Rickets results from the same underlying process, occurring in children and adolescents before the growth plates have closed.
What are the symptoms of osetomalacia?
Bone pain/tenderness
Proximal muscle weaknessBone pain/tenderness
Proximal muscle weakness
What are the symptoms of rickets?
Bowing tibia Bone pain Frontal bossing Rachitic rosary (expansion of the anterior rib ends at the costochondral junctions and is most frequently seen in rickets as nodularity at the costochondral junctions) Pigeon chest Delayed walkingBowing tibia Bone pain Frontal bossing Rachitic rosary (expansion of the anterior rib ends at the costochondral junctions and is most frequently seen in rickets as nodularity at the costochondral junctions) Pigeon chest Delayed walking
What are the risks factors for Osteoporosis?
Increased age Female Smoking Poor diet Low BMIIncreased age Female Smoking Poor diet Low BMI
What are the risks factors for Osteomalacia/rickets?
Poor diet Malabsorption CLD (chronic liver disease) CKD lack of sunlightPoor diet Malabsorption CLD (chronic liver disease) CKD lack of sunlight
What are the risks factors for Hyperparathyroidism??
Secondary hyperPTH --> CRF Decreased vit D MalabsorptionSecondary hyperPTH --> CRF Decreased vit D Malabsorption
What are the risks factors for Pagets disease?
> 50 years
Caucasian> 50 years
Caucasian
What is seen on X-ray for Osteoporosis?
Usually nothing
What is seen on X-ray for Osteomalacia/Rickets?
Looser’s zones (pseudo fractures)
Splaying of metaphysisLooser’s zones (pseudo fractures)
Splaying of metaphysis
What is seen on X-ray for HyperPTH?
Browns tumours
Salt and pepper skull
Subperiosteal bone resorption in phalangesBrowns tumours
Salt and pepper skull
Subperiosteal bone resorption in phalanges
What is seen on X-ray for Pagets?
Mixed lytic and sclerotic
SKULL: Osteoporosis circumscripta
Cotton Wool
VERTEBRAE: Picture frame
Ivory vertebrae
PELVIS: Sclerosis and lucencyMixed lytic and sclerotic
SKULL: Osteoporosis circumscripta
Cotton Wool
VERTEBRAE: Picture frame
Ivory vertebrae
PELVIS: Sclerosis and lucency
What are browns tumours
The brown tumor is a fibrotic, cystic bony change that arises in settings of excess osteoclast activity, such as hyperparathyroidism. These lesions are termed “Brown Tumors” due to the presence of old hemorrhage in the lesion.
What are salt and pepper skulls?
Salt and pepper sign of the calvaria refers to multiple tiny hyperlucent areas in the skull vault caused by resorption of trabecular bone in hyperparathyroidism. There is loss of definition between the inner and outer tables of the skull and a ground-glass appearance as well as spotty deossification.
What are ivory vertebrae
The term ivory vertebra refers to a single sclerotic vertebra, that stands out due to its very dense white appearances, like the ivory tusks of an elephant. Often seen in pagets
What is the histology of Osteoporosis?
Loss of cancellous bone
What is the histology of Osteomalacia/rickets?
Excess of unmineralized bone (osteoid)
What is the histology of HyperPTH?
Osteitis fibrosa cystica (marrow fibrosis + cysts - aka brown tumour)
What is the histology of Pagets disease?
Huge osteoclasts w > 100 nuclei
Mosaic pattern of lamellar bone (like a jigsaw puzzle)
What is the biochem of Osteoporosis?
Normal Ca
Normal PO4
Normal ALP
What is the biochem of Osteomalacia/rickets?
Normal or low Ca
Decreased PO4
Increased ALP
What is the biochem of HyperPTH?
Increased Ca
Decreased or normal PO4
Increased or normal ALP
What is the biochem of Pagets disease?
Normal PO4
+++ increased ALP
What is the biochem of Renal osteodystrophy?
Decreased Ca
Increased PO4
Secondary hyperPTH
Metabolic acidosis
