6 - childhood growth Flashcards
difference between cumulative height and height velocity
cumulative height = how tall the child is now as a total of all the growth they’ve done from conception
height velocity = how fast a child is growing per year
what constitutes normal growth
growing along a centile - can have short children from tall parents but as long as they continue growing along their centile e.g. 25th (25% of children shorter than 25th centile) its fine
hormonal control of growth (axis and also factors/hormones at different ages)
factors e.g. age, nutrition, health, puberty in to the hypothalamus and affect release of GnRH (+) and SS (-)
these act on the pituitary.
Pituitary release GH in pulses (mainly overnight)
GH causes growth
also acts on liver, bones and muscles –> release IGF-1 –> growth
Infancy - nutritionally dependent before 1year
9-12 months - influence of GH
childhood - nutrition less impact
puberty - sex steroids and GH – pubertal growth spurt and epiphyseal growth plates fuse
factors that influence childhood growth
events before birth e.g. poor foetal growth, low BW, prematurity genetics e.g. inherited growth disorders Malnutrition Malabsorption Randomness
what is abnormal growth
causes of short stature
a child who falls significantly in their centile position
- malnutrition
- genetic illness - achondroplasia (short leg length - use standing height vs sitting height); Turner’s; Down syndrome
- chronic disease e.g. asthma, sickle cell disease, chronic arthritis, IBD, CF, renal failure, congenital HD
- endocrine causes e.g. low GH, thyroid hormone, steroid excess
- psychological stress and neglect (effect pulsatility of GH)
causes of tall stature
- Marfan and Soto syndrome
- tall parents
- GH hormone excess from pituitary tumour
- precocious puberty (early growth spurt)
how obesity is measured in children
complications
having a BMI centile position above 85th centile
T2DM orthopaedic problems PCOS CVS risk Cancer Psychological
Possible genetic factors in obesity (polygenic and monogenic)
polygenic = highly heritable that — FTO gene can affect behaviour and appetite - more likely to gain weight
monogenic = rare — leptin deficiency, leptin R deficiency, POMC deficiency, MC4R deficiency