Postnatal Growth Flashcards
What do you need to grow?
- Good general health
- normal nutrition and genetics
- adequate nutrition
- Caring environment
you can be short normally or due to growth restrictions>
Abnormal Growth can be due to what disorders/diseases
- Genetic disorders
- Endocrine (hormone) disorders
- Cartilage/bone disorders
- General Chronic DIsease
Early detection and treatment of underlying conditions can enable many children experiancing abnormal growth to reach their potential
What are the 3 post-natal phases of growth?
The Karlberg model
- Infancy you achieve half your height by age 2
- Rapid Growth at birth, which declines over the first 2 years of life; less GH dependent
- So if you have a condition of an impaired liver, you will be really short as no GH
- School age
- Constant annual Growth- GH dependent!
- Adolescant
- Rapid growth primarily dependent on sex steroids and increased GH release
Humans follow a _________ gradient of growth.
From birth to puberty, the ____ grow relatively faster then other pot-cranial body segments.
Humans follow a Cephalo-caudal gradient of growth.
From birth to puberty, the legs grow relatively faster then other pot-cranial body segments.
- Why you have such a big head as a baby!
How to calculate Mid parental Height.
MPH= M(cm) + F(cm) +/-13cm /2
MPH range +/- 8cm
The MPH can be plotted on a growth chart to estimate the centile the baby should be growing along.
What does crossing the centile line mean?
Everyone should following along a line on a growth chart. “crossing the centile” is when you drop off that line and this means there’s abnormal growth issues occuring.
What does height velocity tell us?
Differntiates between normal short stature and pathological short stature
- Calculates over a 6-12 month interval (to reduce measurement errors), tracks over time
- ‘Normal’ HV: within 25-75th centile
What does this graph show us?
Early Bloomers: peak in year 7, have a massive growth sport and be really good at sport and then stop growing by 13-16
Delayed Growth: Don’t have growth spurt till later, could still be growing in university
Differences between girls and boys height velocities?
Girls: earlier growth spurt ~12yrs
Boys: Grow more, later ~14yrs
SO around a 2 year difference due to hormones made. Eostrogen primary driving for growth, and because girls mainly only have that they grow and fuse epipihysis earlier.
Boys also do everything but eostrogen, but can convert Testosterone to eostrogen. This takes longer, so they grow later.
The primary hormone for growth spurts?
Oestrogen!
**why boys get man boobs during puberty
Short Stature is?
- A common clinical presentation
- A symptom, or a varient (so doesn’t have to be bc of disease)
- but may indicate pathology
- Short statured people can grow with normal velocity
- Is one of the commonest manifestations of chronic illness
What do you take in a short stature history?
- Mother and Father Heights
- MPH= M(cm) + F (CM) +/-13/2 (MPH range +/- 8 cm)
- Delayed Puberty:
- Girls >14yrs menarche in females
- Males continued growth after high school
- **also look at other siblings growth patterns
How do you differentiate between Growth Disorder and normal?
Normal Height Velocity= normal variance
Familial short stature or
Constitutional delay in growth and development (‘late bloomer’)
Poor Height Velocity= usually pathological
Proportionate
Disproportionate (off sitting height vs arm span)
What does bone age tell us about Growth?
- Gruelich and Pyle Standards (xray atlas)
- Take lots of pictures, and estimate an ‘age’ via 1 yr intervals
- Allows estimation for final height prediction
- Predicted Adult Height (PAH) from bone age
- If it’s too high or too low in comparison to normal age you know there’s an issue!
Normal variant short stature and how do you know it is normal?
Either familial short stature or have delyaed growth/development.
Account for 95% of children who present with short stature
HALLMARK is NORMAL HEIGHT VELOCITY and look at the bone age (very delayed is >2yrs younger then should be)
use the differentials between them to diagnose
What’s the difference between FSS and CDGD in
Bone age
Puberty
Final Height
Why are hormones important?
Remember every hormone is within its own loop (feedback)
What is Growth Hormone secretion like and whats it increased/decreased by?
- Pulsatile with a low baseline
- Episodic and Pulsatile
- Primarily at night (stages III-IV sleep)
- So no point in measuring during the day
- Make heaps when you’re young, and decreasing with age
Increased by: sleep, exercise, stress, hypoglycaemia, aminoacids, malnutrtion, sex steroids
Decreased by: Obesity, psychosocial deprivation (kids in bad homes are short)
How does Nutrition link in with the Growth Hormone Axis?
For normal hepatic IGF-1 production you need
- Normal levels of insulin
- Normal nutrition
Malnutrition (inadequate calories) or poorly controlled diabetes (inadequate insulin) inhibits hepatic IGF-1 production.
Why liver failure ⇒ very short kids
Actions of Growth Hormones
Metabolic:
- Inhibits glucose uptake and promotes glycogenolysis (anti-insulin)
- Stimulates protein synthesis
- Promotes lipolysis
Can be endocrine, paracrine and autocrine.
Very similar receptor to insulin
Makes you make an IGF-1
IGFs (somatomedins)
- IGF-1 (somatomedin C) and IGF 2
- IGF-1 (lots of levels you go hypoglycaemic), IGF 2 and insulin (lots makes you grow) hae significant hormonology
- Each receptor has cross reactivity with the other receptors (weak)
IGF-1 Receptor Defect: live a normal life, normal fertility, just veeeeeery short: “Laron Dwarf”
Different alleles of IGF1 makes you grow different
IGF binding proteins?
All circulating IGFs are bounf to IGFBPs (>6 characterised)
What does eostrogen affect in terms of growth?
- Effects on skeleton and body composition
- Estrogen has a greater effect then testosterone on the skeleton!
- Responsible for epiphyseal maturation/closure in both sexes!
- If someone gave a girl the pill during her growth spurt she’ll stop growing!!!!!
- Treatment for extremely tall people
- If you can’t make estrogen you’ll keep growing! But bones will be osteoporotic and weak!
Hypothyroidism?
And what’s the role of thyroid hormones?
- You make tons of TSH → goitre
- Very malnourished, short and slow
Thyroid Hormones (Y3 an T4) have a ‘facilitatory’ role in growth
Not enough → slow growth
Too much → too fast growth
- Neccessary for normal GH secretion
- Neccessary for growth plate development
- and body proportions
What does insulin provide?
A substrate for growth. (amino acidd uptake, glycogenesis and lipogenesis)
Has a facilitatory role in growth
We know this from the malnutrition/poor growth from babies/kids with Type 1 diabetes!
So what Growth Promoting Hormones are important in the Fetus
Important:
- IGF II
- Insulin
Less important
- Human placental lactogen
- T4/3, IGF-I
**GH only has asmall role to play in growth promotion during fetal life and early infancy
So what Growth Promoting Hormones are important in Children
Important:
- GH
- IGF I
- T4/3
Less Important
- Insulin
IUGR: Intra uterine growth restriction
- Intra uterine growth retardation or SGA
- Very common
- Birthweight <10th centile for gestational age
- Catchup growth above the 3rd centile usually occurs by 6 months but may drag on to 2 years.
- Short stature by 2 years = indicates short final height
- DOn’t usually reach MPH
Turners Syndrome
- Missing X chromosome usually (Karyotype XO)
- abnormal/absent ovaries
- Consider in all girls with unexplained short stature of height below MPH range
- Commonest feature is short for MPH (100%)
- 50% will only have short stature as clinical feature
- can also have poor HV or delayed puberty
- Low Bone age
- Have elevated FSH and LH (primary gonadal failure)
Treatment for Turners Sydrome?
Hormonal Therapy: effective at getting girls upto around 5ft
Untreated: around 4 ft
But some girls with tanners syndrome are ‘normal height’ due to genetics!
Achondroplasia
- Defect of Growth Plate receptor → dwarfism
Growth Hormone Excess: Acromegaly
- TOo much GH
- Makes you tall when you’re a kid
- Makes your jaw massive when you’re an adult
- Lots of bony overgrowth
Low growth hormone, but nothing can be done by 17/18 years
