Growth in childhood Flashcards
What is commonly plotted in centile charts?
- head circumference
- weight
- height/length
- leg length
- BMI
- growth velocity
How is height velocity calculated and what are its units?
- (height now - height last visit) / (age now-age last visit)
- cm/yr
Describe the hormonal growth axis
- Hypothalamus releases Somatostatin (-) or GHRH (+)
- Acts on somatotrophs of the anterior pituitary
- Releases growth hormone
- Acts on GH receptors to have its action and to stimulate IGF-1 production
- IGF-1 acts on IGF-1 receptor to have its action
In what manner is GH released?
Pulsatile
What influences GH secretion?
- Nutrition
- Sleep
- Exercise
- Stress
What kind of hormone is GH?
Single chain polypeptide
What is infant growth dependent on?
- Nutritionally dependent
- GH dependent for 9-12 months
What is childhood growth dependent on?
- Less dependent on nutrition
- GH/IGF-1 axis main driver of growth
Explain this height velocity graph
- Growth is highest in the antenatal phase
- Decreases during infancy into childhood
- Spikes again during puberty (driven by GH and sex steroids)
- girls puberty is earlier than boys
- Decreases again to a standstill after puberty
What happens to the bones when we stop growing?
- The bones mature and epiphyses fuse at the end of puberty.
- The final part of growth occurs in the spine
- The final epiphyses to fuse are in the pelvis.
What is the use of centiles?
- Centiles are not a “normal range”
- Most children set out on a centile by about 2 years and grow on the same centile during childhood.
- Pattern of growth is more important than position on the centiles.
- A child who falls significantly in centile position is not growing normally, whatever their height.
What are some causes of short stature?
- Genetic (main one)
- Pubertal and growth delay
- IUGR/SGA
- Dysmorphic syndromes
- Endocrine disorders
- Chronic paediatric disease
- Psychosocial depravation
What can be the consequence of IUGR on growth?
- Not all children with intrauterine growth restriction catch up completely.
- Growth will be normal in childhood but they have “lost” some height in the antenatal period.
What endocrine problems can cause short stature?
- hypothyroidism
- growth hormone deficiency
- steroid excess
What syndromes can casue short stature?
- Turner syndrome XO
- Down syndrome T21
- skeletal dysplasias
Why do significant childhood illnesses cause short stature?
Significant illnesses can interfere with growth because of:
- Inflammation
- Poor nutrition
- The effects of drugs such as steroids.
Give some examples of chronic paediatric diseases that cause short stature
- Asthma
- Sickle cell
- Juvenile chronic arthritis
- Inflammatory bowel disease
–Crohns disease
–Coeliac disease
- Cystic fibrosis
- Renal failure
- Congenital heart disease
What are the causes of tall stature?
- tall parents
- early puberty
- syndromes eg Marfans
- growth hormone excess
What are the negative impacts of obesity?
Emotional:
- Stigmatism
- Bullying
- Low self-esteem
School absence
Health:
- High cholesterol
- High bp
- Diabetes
- Bone and joint issues
- Breathing difficulties
What conditions does obesity pre-dispose you to?
- Type 2 diabetes
- Orthopaedic problems
- Polycystic ovarian disease
- Cardiovascular risk
- Psychological problems
- Cancer
- Respiratory difficulties
How is obesity assessed in children?
Position on the BMI centile for their age
What syndromes are associated with obesity?
- Cushings
- Prader-willi
- Lawrence-moon-biedl
What are the genetics of weight?
Polygenic inheritance
Weight is highly heritable
List examples of monogenic obesity syndromes
- Leptin deficiency
- Leptin receptor deficiency
- POMC deficiency
- PC-1 deficiency
- MC4R deficiency
