Metabolic Bone Diseases Flashcards
This deck covers
Paget’s Disease
Rickets/Osteomalacia
Osteogenesis Imperfecta
What is Paget’s Disease?
A localised disease of increased but uncontrolled bone turnover
Resorption increases and leads to increased formation
Typically affects old men
What effect does Paget’s disease have on bone?
It becomes extremely disorganised:
- Bigger
- Less Compact
- More vascular
- More susceptible to deformity & fracture
What bones are most commonly affected in Pagets disease?
Skull
Spine & pelvis
Long bones of lower extremities
Describe the typical presentation of Paget’s disease
Majority asymptomatic with incidental finding of raised ALP
If symptomatic:
- bone pain - deep, boring
- deformity - bowing of tibia or bossing of skull
What are some complications of Paget’s disease?
Note - as its usually asymptomatic, these may be the presentations/first symptoms
Fractures
Deafness
Osteosarcoma
Skull thickening
How do we test for Paget’s disease?
What findings are in keeping with it?
Blood tests:
Raised ALP with normal Ca2+ and Phosphate
LFTs
Can x-ray for lytic lesions and thickened bone cortices
how do we treat Paget’s?
IV bisphosphonates
(Zoledronic acid)
Only indicated when symptomatic, affecting the skull or in area requiring surgical intervention
What are rickets and osteomalacia?
Diseases of insufficient bone mineralisation due to a deficiency of Vit D or Ca
What’s the primary difference between rickets and osteomalacia?
Rickets = in growing kids
Osteomalacia = in adults*
(*following closure of growth plates)
How do Rickets and osteomalacia each affect the structural integrity of the bones?
Rickets - problems are more to do with growth of bones:
- softening
- impaired growth
- malformations
Osteomalacia - affects bones once fully formed:
- weakening - thus more associated with fractures
- softening
What are the typical features of rickets?
Skeletal deformities:
- Bow legged (younger) - varus
- Knocked knees (older kids) - valgus
- (more in another slide)
Growth retardation & failure to thrive
Hypotonia (low Vit D)
What skeletal deformities may be seen in Ricket’s?
Bow legs (varus)
Knocked knees (valgus)
Wide joints (wrists, elbows, ankles)
Kyphoscoliosis
Rickety rosary (deformed ribs)
Frontal bossing of skull
What are the features of osteomalacia?
In adults with:
- Bone pain/tenderness
- Proximal myopathy (waddling gait)
- Increased falls & fractures
How do we test for Rickets & Osteomalacia?
What results would be in keeping?
Bloods:
- 25-OH Vit D - low
- Calcium - low
- Phosphate - low
- ALP - high
- PTH - high
Xray?
Bone biopsy?
How do we treat Rickets & osteomalacia?
Look for any thing that could cause a deficiency e.g. Liver damage, anti-convulsant drugs, renal failure or malabsoption disorders
Assuming it’s a primary deficiency then treat with Ca & Vit D supplements
What is Osteogenesis Imperfecta?
A genetic disorder of absent/defective type 1 collagen that is characterized by incredibly fragile bones - leading to fractures due to mild trauma or activities of daily living
When does OI onset?
Can be from pre-natally fatal all the way up to 40yr olds diagnosed with “Early onset OP”
How does OI present?
Main thing is easy fractures but also:
- Growth deficiency
- Dentigenesis imperfecta
- Hearing loss
- Blue sclera (Vitreous humour is blue, the sclera become see through)
- Scoliosis or barrel chest
- Ligamentous laxity
- Easy bruising
What is ligamentous laxity?
How is this scored?
An effect of OI, essentially its joint hypermobiltiy
Scored using the beighton score
How do we manage osteogenesis imperfecta?
Surgical management of fractures
IV bisphosphonates to prevent fractures
Education & Social adaptations to prevent fractures
Potentially genetic counselling
