introduction to common bone disorders

Download Introduction to Common Bone Disorders

Post on 16-Jul-2015




0 download

Embed Size (px)




ObjectiveBy the end of this seminar, we should beable to understand:Bone and its importanceDivision of bone disordersBrief characteristics of each bone disease

What is Bone?Bone is living tissue that provides shape and support for the body, as well as protection for some organs.

Bone also serves as a storage site for minerals and provides the medium(marrow) for the development and storage of blood cells.

Bone diseaseRefers to the medical conditions which affect thebone. Itis a condition that damages the skeleton and makes bones weak and prone to fractureCongenital Disease of BoneDysostoses (Congenital Malformations)Due to mutations in homeobox genes affecting localized migration and condensation of primitive mesenchymal cells.

Result in the absence of bones, supernumerary bones, or abnormal fusion of bones. Dysplasias (Abnormalities in bone organogenesis)Mutations that interfere with bone or cartilage growth and maintainance of normal matrix components.

Result in achondroplasia, osteogenesis imperfecta and osteopetrosis.

1. Osteogenesis ImperfectaBrittle Bone Disease

Caused by abnormal type I collagen synthesis

resulting in bone fragility and susceptibility to fractures.

The words "osteogenesis imperfecta" mean bone that is imperfectly made from the beginning of life7

2. AchondroplasiaPoint mutation in the fibroblast growth factor receptor 3 (FGFR3) that results in its constitutive activation.

Inhibits chondrocyte proliferationSuppress expansion of normal epiphyseal growth plateSeverely stunted long bone growth Normal epiphyseal growth plate expansion is suppressed and long bone growth is severely stunted83. Osteopetrosis A group of rare genetic disorders characterized by reduced osteoclast-mediated bone resorption defective bone remodelling

Result in dense but architecturally unsound bone

Acquired/Metabolic Bone DiseaseDisorders of bone strength, usually caused byabnormalities of minerals (such as calcium orphosphorus), vitamin D, bone mass or bonestructure.

OsteoporosisPaget Disease (Ostitis Deformans)Rickets and OsteomalaciaHyperparathyroidism

1. OsteoporosisThe most common bone disease.

This condition is caused by a reduction in bone density, which leads to more fragile bones and a higher risk of fractures.

112. Paget Disease (Ostitis Deformans)The bone remodeling is disturbed and not synchronized.

The net effect of this process is a gain in bone mass ; however, the newly formed bone is disordered and lacks strength

This unique skeletal disease is characterised by repetitive episode of frenzied, regional osteoclastic and bone resorption (osteoclastic stage), followed by exuberant bone formation (mixed osteoclastic-osteoblastic stage), and finally by an apparent exhaustion of cellular activity (osteosclerotic stage).123. Rickets and OsteomalaciaManifestations of vitamin D deficiency or its abnormal metabolism

Defective bone mineralizationoverabundant non-mineralised osteoid

This contrasts with osteoporosis, where the mineral content of the remaining bone is normal, but the total bone mass is decreased. 134. HyperparathyroidismPrimary or secondary over production of PTH (hyperparathyroidism)

Increased osteoclast activity and bone resorption

fractures and deformitiesArthritis Arthritisis one of the most common conditions in the world.

Arthritis literally means joint inflammation.

CONCLUSION Importance of bones:SupportProtection Storage siteMediumDivision of bone disorders:Congenital Acquired

References Robbins Basic Pathology, 8th Edition, Kumar, Elsevier

THANK YOU Any Question?