NMS pathology section Flashcards
What is the normal mechanism of Achondroplasia?
Activation of FGFR3.
What is the pathologic mechanism of achondroplasia?
mutation leads to r/c being in constant state of activation
What disease is also caused by a defect in FGFR3?
Thanatophoric dwarfism
What will the FGFR3 do once activated?
Inhibit cartilage proliferation.
What fails to grow in achondroplasia?
longitudinal bone growth, leads to short limbs
What kind of trait is Achondroplasia?
Autosomal-dominant
What is the prognosis in achondroplasia?
normal life span and fertility
What is osteopetrosis?
thick bones resulting from defect in the function of osteoclasts
Is membranous ossification affected in achondroplasia?
no
Osteopetrosis is caused by what?
A genetic deficiency of carbonic anhydrase II.
what is the most common lethal form of dwarfism?
Thanatophoric dwarfism
What is the prevalence of T.D?
1/20,000
What are some physical characterisitics of a person with TD?
micromelic limbs, frontal bossing with relative macrocephaly, small chest cavity, bell shaped abdomen. (Gummi bear)
what leads to death at birth in TD?
underdeveloped thoracic cavity leads to respiratory insufficiency
What is osteopetrosis AKA?
marble bone disease, and Albers-Schonberg disease
What is osteopetrosis a failure of?
failure of normal bone resorption → thickened, dense but brittle bones
What would levels of serum Ca, P and alkaline phosphatase be like in Osteopetrosis?
normal
What can x-rays of osteopetrosis show?
Erlenmeyer flask bones.
Erlenmeyer flask bones that flare out can result in what?
Cranial nerve impingment, and palsies due to narrowed foramina.
What is the most common fracture with aseptic bone necrosis?
Femoral head.
What are some known causes of aseptic bone necrosis?
trauma, emboli, drugs, radiation
What is the most common fracture with aseptic bone necrosis in the carpal bones?
Navicular (scaphoid).
What are patients with autoimmune rheumatic disorders at increased risk of?
atherosclerosis
What is the cause of EF?
Unknown.