Chapter 26: Bones Disorders of the Growth Plate and Remodeling Flashcards
Child presents with limbs disproportionately short in relation to the trunk and with an unusually large head.
Cretinism resulting from maternal iodine deficiency.
TH regulates chondrocytes, osteoblasts, and osteoclasts through production of cytokines and other factors involved in bone development and growth.
Linear development impaired.
Delayed closure of frontanelles of skull -> Large head
Delay closure of epiphyses and stippling of these zones.
Shedding of deciduous teeth and eruption of permanent teeth are retarded.
**Maturation of the hypertrophied zone is retarded, the zone of proliferative cartilage is narrow. Therefore Endochondral ossification does not proceed appropriately, transverse bars of bone in metaphysis seal off the growth plate. Radiography will show incomplete penetration of the secondary centers of ossification into the epiphysis.
Child prevents with severe dwarfism, dental defects, mental retardation, corneal opacities, and increased urinary excretion of keratin sulfate.
A defect is discovered in a mucopolysaccharide gene.
Morquio Syndrome (Mucopolysaccharidosis type IV)
Patient presents with short-limbed dwarfism and macrocephaly.
Biopsy shows greatly thinned growth plate with absent zone of proliferative cartilage, and a transverse bar of bone seals off the growth plate.
Secondary centers of ossification and the articular cartilage are normal.
Achondroplasia. Caused by an activating mutation in FGFR3 gene, which constitutively inhibits chondrocyte differentiation and proliferation, which retards growth plate development.
Because intramembranous ossification is undisturbed, the periosteum functions normally and bones become short and thick.
A patient presents with impaired wound healing and bone growth. Widespread capillary bleeding is observed, as well as joint and muscle pain.
The patient’s diet suggests a vitamin deficiency.
Scurvy - Vitamin C deficiency.
Lack of hydroxyproline and hydroxylysine, which stabilize collagen and cross-link tropocollagen. Lack of osteoblastic function. Lack of Woven bone, Chondrocytes continue to proliferate.
A patient presents with abnormal lateral curvature of the spine.
Scoliosis.
For an unknown reason, one portion of a vertebrae endplate grows faster than the other, producing lateral curvature.
A patient presents with abnormal anteroposterior curvature of the spine.
Kyphosis.
A patient presents with a cartilaginous mass extending into surrounding soft tissue that is in direct continuity with the parent bone. It lacks an underlying cortex and is surrounded by perichondrium.
Osteochondroma - arises from a defect at the ring of Ranvier of the growth plate.
Usually guides growth plate cartilage growth towards the metaphysis.
Hereditary multiple osteochondromatosis caused by loss of EXT1 or EXT2.
Patient presents with asymmetric limbs, one much longer than the other. A history of the metaphyseas of the longer limb is obtained.
Hemihypertrophy - one limb’s growth plate stimulated to undergo rapid and prolonged endochondral ossification.
Caused by infection, AV malformation, fractures and tumors. Isolated hemihypertrophy increases neoplasm risk.
A patient presents with arm pain. A radiograph is obtained and shows this. The lesion is removed. What is it?
Osteochondroma
A child presents with pancytopenia, splenomegaly, and abnormal vision and hearing. An X-ray shows the following findings. What is the disease, and what is the treatment?
Osteopetrosis. GIve a bone marrow transplant - functional osteoclasts.
Due to defects in osteoclastic bone resorption. Usually due to poor bone acidification - proton pump, carbonic anhydrase II gene.
Pancytopenia due to overgrowth of bone destroying the marrow space.
AKA “Marble Bone DIsease”, AlbersSchonberg
A child presents with pain, fatigue, muscle wasting, atrophy, and gait abnormalities.
Investigation reveals symmetric thickening and increased diameter of the diaphyses of long bones.
Progressive diaphyseal dysplasia (Camurati-Engelmann disease).
AD disorder of children, cylinderization does not proceed appropriately. Increased bone formation linked to TGF-beta propeptide.
