Bone diseases Flashcards
What is Osteogenesis Imperfecta?
Group of autosomal dominant inherited connective tissue caused by mutations in the gene for type I collagen.
What can excessive levels of Growth hormone cause before puberty?
Gigantism through promotion of epiphyseal growth plate activity.
What can insufficient Growth hormone cause before puberty?
Pituitary dwarfism
What can excessive Growth hormone cause in adults?
Increases bone width by promoting periosteal growth (ACROMEGALY)
What do Sex hormones influence?
Development of ossification centres
How can Precocious sexual maturity develop?
Sex hormone producing tumours retard bone growth due to premature fusion of epiphyses
How can a deficiency in sex hormone cause tall stature?
Epiphyseal growth plates don’t fuse so prolonged bone growth
What can deficiency in thyroid hormone lead to?
Cretinism
What is Osteoporosis?
Metabolic bone disease in which mineralised bone is decreased in mass to the point it can no longer provide support.
What are the 2 types of Primary Osteoporosis?
Type I and II
What group of people does Type I Osteoporosis generally occur in?
Postmenopausal women
What group of people does type II Osteoporosis generally occur in?
Elderly people
What are the risk factors for osteoporosis?
Genetic Lack of calcium or vitamin D Immobilisation Smoking Age
What is Achondroplasia?
Common form of short limb dwarfism
Autosomal dominant point mutation in FGFR3
How can the body get vitamin D?
Dietary
Synthesised by the skin using IV light
What happens to vitamin D in the body?
Hydroxylation in the liver and further ones in the kidney leads to 1, 25 dihydroxyvitamin D3.
What does dihydroxyvitamin D3 do?
Increases calcium absorption by the small bowel
Promotes mineralisation of bone
What causes Rickets?
Lack of vitamin D so bones do not harden
What are the effects of rickets?
Bones become soft and malformed
Distortion of the skull bone
What is Osteomalacia?
Adult counterpart of rickets.
What are symptoms of Osteomalacia?
Bone pain
Back ache
Muscle weakness
What happens to the trabeculae of cancellous bone in Osteomalacia?
An abnormally large amount of non mineralised bone covering the surface so they’re weakened.