Metabolic Diseases of the Bone Flashcards
What is craniorachischisis?
- defects in nuclear protein
- transcription factor (homeobox gene)
- dyostoses
- failure of closure of the spinal canal and skull
What is the pathology in achondroplasia?
- FGFR3 mutation –> no inhibition of cartilage proliferation
- ## abnormal body proportions
What are the features of osteogenesis imperfect and the cause?
- genetic disorder of Type 1 collagen
- four types
- most are autosomal dominant, most spontaneous
- affects all CTs
- decreased osteoblasts
- sparse cancellous bone
- prone to fracture
What are the different types of OI?
Type 1 - 60-80%, normal stature, hyperextendibility, hearing loss, average life expectancy, blue sclera (less collagen, can see underlying colloid)
Subtype B - dentinogenesis imperfecta, affects all teeth, translucent discoloured teeth, enamel fracture short roots, periodical lucencies
Type II - fatal perinatal or intrauterine, abnormal extremities and skull, blue black sclera
What is osteopetrosis?
How is it treated?
(Marble bone disease/Albers-Schonberg disease)
- carbonic anhydrase II deficiency, enzyme required for acidification and excretion of hydrogen ions
- reduced osteoclast bone resorption
- characterised by systemic sclerosis
Treated with bone marrow transplant
What are the causes of primary osteoporosis?
- post menopausal
- disuse
- senile
What are the causes of secondary osteoporosis?
- hyperparathyroidism
- hypothyroidism
- multiple myeloma
Drugs - corticosteroids, anticoagulants, chemotherapy
What is the 5 possible pathogeneses of osteoporosis?
- reduced osteoblastic activity –> low turnover
- reduced physical activity
- genetic factors - polymorphism of VitDR
- nutritional status
- hormonal influence
What is the histological findings in osteoporosis?
- large spaces
- thinned trabeculae
What is Paget’s disease?
- disease caused by osteoclast dysfunction
- caused by paramyxovirus infection
- more osteoclasts than osteoblasts
- osteolysis –> mixed phase –> osteosclerosis
What is the histological appearance of Paget’s disease?
- mosaic pattern
What are the complications of Paget’s disease?
- sarcoma
- metastatic carcinoma
- haematological malignancies
- giant cell tumour
What is osteomalacia?
- poor calcification causing a delay or failure of bone matrix mineralisation usually caused by VitD deficiency or a disturbance in its metabolism
What is rickets?
Osteomalacia happeing before the epiphyses have fused
- tender swollen joints, deformities,
What are the causes of primary hyperparathyroidism?
- adenoma
- hyperplasia
- parathyroid carcinoma
