Pathoma: Skeletal System Flashcards
(55 cards)
What is achondroplasia?
impaired proliferation on the growth plate…dwarfism
Genetic mutation cause of achondopliasia?
Activating mutation in fibroblast growth factor receptor 3 (FGFR3)
Process of endochondrial bone formation?
Formation of cartilage matrix which is then replaced by bone
Process of intramembranous bone formation?
Bone formation without preexisting cartilage matrix
What are the clinical features of someone with achondroplasia?
Short extremities with normal sized head and chest
Normal mental function, lifespan and fertility
What is osteogenesis imperfecta?
Congenital defect of bone formation resulting in structurally weak bone
What is the mutation found in osteogenesis imperfecta?
Collagen type I mutation
Is the OI mutation usually AR, AD, or x linked?
AD
Clinical features of OI?
Multiple fractures of bone
Blue sclera
Hearing loss
What is osteopetrosis?
Inherited defect of bone resorption…thick, heavy bone that fractures easily
Which type of cells are poorly functioning in osteopetrosis?
Osteoclasts
Clinical features of osteopetrosis?
Bone fractures, bone marrow under production, extramedullary hematopoiesis, vision and hearing impairment, hydrocephalus, renal tubular acidosis
Why is there renal tubular acidosis in osteopetrosis?
because it is associated with a CA II mutation (which decreases reabsorption of bicarb and results in a metabolic acidosis)
What is the defect in rickets or osteomalacia?
Defective mineralization of osteoid
Which cells produce osteoid?
osteoblasts
What is the main cause of rickets or osteomalacia?
low vit D–> low Ca and PO4
What are the 3 main actions of vitamin D?
Increase intestinal absorption of Ca and PO4
Increase renal reabsorption of Ca and PO4
Increase bone resporption of Ca and PO4
What are the lab findings in osteomalacia?
Ca, PO4, PTH, alkaline phosphate
decreased Ca
decreased PO4
increased PTH
increased AP
When does someone have their peak bone mass?
30 yo
What is osteoporosis?
reduction in trabecular bone mass leading to porous bones with an increased risk of fracture
What is Paget disease of the Bone?
Imbalance between osteoblast and osteoclast function
THICK, SCLEROTIC BONE that fractures easily
What are the 3 clinical stages of paget disease of the bone?
osteoclastic
Mixed osteoblastic- osteclastic
osteoblastic
What is the histology pattern in Paget disease on biopsy?
Mosaic pattern of lamellar bone
What are the clinical features of Paget disease?
Bone pain, increasing hat size, hearing loss, lion-like facies, isolated elevated alkaline phosphatase
