1. Metabolic bone disease Flashcards
What is osteomalacia a dysfunction of?
Mineralisation
Recall 3 features of osteomalacia
Bone pain due to softness
Proximal weakness
Bone deformity
What are the 2 most likely causes of osteomalacia
- Vit D deficiency
2 Phosphate deficiency
Recall the 3 main functions of vit D
In intestine: increase Ca++ and PO4— absorption
In bone: increase resorption
In kindeys: increase Ca++ resorption and PO4— excretion
What is the most likely cause of a phosphate deficiency?
CKD
Recall the 5 key biochemical features of osteomalacia
Hypocalcaemia Hypophosphataemia High ALP Low calcitriol Secondary hyperPTHism
Summarise the pathophysiology of Paget’s disease
- Renal failure:
a) impairs ability to excrete phosphate, leading to hyperphosphataemia
b) leads to 1-alpha-OHase failure so Vit D left inactivated, leading to hypocalcaemia - Raised serum ALP –> increased bone turnover
In what population is Paget’s most common?
Caucasians >40
Describe the genetic component of Paget’s
Autosomal
Incomplete penetrance
Recall the stages of Paget’s disease
- Osteolytic
- Osteolytic-osteosclerotic
- Quiescent osteosclerotic
Recall 3 unobvious clinical features of Paget’s
Deafness
Nerve compression
Risk to medulla from skull changes
Recall the 2 chief causes of primary hyperPTHism and their relative influence
Parathyroid adenoma (85%-95%) Chief cell hyperplasia (5%-15%)
Where is bone biopsy usually performed?
ASIS
Recall 4 indications for bone biopsy
Investigation of: Unexplained infection X ray abnormality Bone tumour Therapy efficacy
Recall the 2 methods of performing a bone biopsy
Closed: use Jamshidi needle
Open: under general anaesthetic
