Disorders of growth Flashcards
What are some factors that cause disorders of growth?
- Growth plate injury or arrest
- Growth plate over stimulation
- Lack of nutrition
- Vitamin deficiency
- Skeletal dysplasia
- Hormonal
What are some causes of growth plate arrest?
Trauma
Infection
Tumours
Irradiation
Surgery
Compression
These can all partially or fully destroy the growth plate, leading to malformation or lack of growth of bone
Describe the Salter Harris classification of physeal trauma
- S - Straight - The injury occurs straight through the physis
- A - Above - The injury comes from above physis and moves into the physis
- L - Lower - The injury comes from below the physis and moves into the physis
- T - Through - The injury comes from either above or below and passes straight through the physis
- R - cRush - The physis is crushed by the trauma
Dys -
Abnormal
- plasia
Growth
Campto -
Bent
Acro-
Peripheral
Meso-
Middle
Rhizo-
Root/Central
Phoco-
Seal like
-melia
Relating to limbs
Thanato-
Death
Diatrophic
Twisting
Brachy-
Short
Spondylo-
Relating to the spine
Meta-
After or behind
-Petrosis
Stone like
What are the 4 main categories of skeletal dysplasia?
- Chondrodysplasias - Cartilage
- Tumour-like conditions
- Altered bone density conditions
- Storage disorders
What are some examples of chondrodyspasias?
- Achondroplasia
- Pseudoachondroplasia
- SED
- MED
- Metaphyseal chondrodysplasia
- Diastrophic dysplasia
What are some examples of tumour-like skeletal dysplastic conditions?
- Multiple hereditary exostoses
- Ollier’s disease
- Fibrous dysplasia
- Trevor’s disease
What are some conditions that alter bone density?
Osteogenesis imperfecta
Osteoporosis
What are some examples of skeletal dysplastic storage disorders?
Mucopolysaccharidoses:
- Morquio’s syndrome
- Hunter’s syndrome
- Hurler’s syndrome
What is achondroplasia?
Achondroplasia is a spontaneous autosomal dominant condition, and is the most common form of skeletal dysplasia
It is the medical term for short stature (Dwarfism is no longer used)
Describe the pathophysiology of achondroplasia
It causes rhizomelic dwarfism, affecting the proliferative zone of physis, leading to reduced longitudinal growth but normal circumferential growth
What are some presentations of achondroplasia?
- Short stature
- Foramen magnum stenosis
- Adenotonsillar hypertrophy
- Hyperlordosis of the lumbar spine
- Macrocephalt
- Trident hands
- Brachydactyly
- Champagne glass pelvis
What causes multiple hereditary exostoses?
Multiple hereditary exostoses is caused by an EXT gene mutation
Describe the pathophysiology of multiple hereditary exostoses?
In this, benign cartilage-covered bony lesions form from the metaphyses, which can put pressure on local structures, cause reduced range of movement and distort growth
The lesions usually stop growing when the physes fuse
What is a possible risk of multiple hereditary exostoses?
These lesions, if the cartilage cap thickens, can undergo malignant transformation
What is osteogenesis imperfecta?
Osteogenesis imperfecta, also known as brittle bone disease, is a rare group of genetic disorders mainly affecting bone
What causes osteogenesis imperfecta?
Oestogenesis imperfecta is caused by a defect in the maturation and orginisation of type I collagen, which accounts for most of the organic composition of bone
The majority of cases are autosomal dominant, however, there are some rarer, autosomal recessive types
How will autosomal dominant osteogenesis imperfecta present?
- Multiple fragility fractures in childhood
- Short stature with multiple deformities
- Blue sclera
- Scoliosis
- Coxa vara
- Mitral valve prolapse
- Dentinogenesis imperfecta (Disorder of tooth development)
How will autosomal recessive osteogenesis imperfecta usually present?
Autosomal recessive osteogenesis imperfecta is usually either fatal during the perinatal period or is associated with spinal deformity
How is osteogenesis imperfecta usually diagnosed?
Diagnosis is usually made using x-ray which will show thin bones with thin cortices
The bones will be osteopenic
In mild cases, x-rays may be relatively normal woth a history of low energy fractures
How is osteogenesis imperfecta usually managed?
There is no cure for osteogenesis imperfecta, however, biphosphonates can be used to inhibit osteoclast activity
Most management is conservative with fracture fixation, deformity correction surgeries and splintage to aid healing and prevent callus formation as fracture heal abnormally
What are muscopolysaccharidoses?
These are a group of conditions, in which there is an accumulation of glycosaminoglycan (GAG) breakdown products in multiple organs
What are GAGs?
GAGs are carbohydrates used in connective tissue formation
What are some examples of mucopolysacharidoses?
- Morquio’s syndrome
- Hunter’s syndrome
- Hurler’s syndrome
What are some signs and symptoms of mucopolysaccharidoses?
- Proportionate dwarfism
- C1-2 cervical instability
- Abnormal epiphyses
- Bullet shaped phalanges
- Genu velgum (Bow legs)
- Orgaomegaly
- Cardiac disease
- Deafness
- Reduced IQ
