Lecture 23 - 208/2017 Flashcards
What does normal growth depend on?
- Good general health.
- Normal nutrition and genetics.
- Adequate nutrition.
- Caring environment.
What are the causes for abnormal growth?
- Genetic disorders.
- Endocrine disorders.
- Cartilage or bone disorders.
- General chronic disease.
What are the phases of growth?
- Infant - rapid growth during the first two years of life (less GH dependent).
- Childhood - constant annual growth (GH dependent).
- Puberty - rapid growth primarily dependent on sex steroids and increased GH release.
Describe proportion changes in growth?
Human beings follow a cephalo-caudal gradient of brith. From birth to puberty the legs grow relatively faster than other post-cranial body parts.
What is the mid-parental height (MPH) range?
This is what can determine the potential height of the person.
What is the MPH for a boy?
MPH = Father + (Mother +13cm) / 2 +/- 8cm (range)
What is the MPH for a girl?
MPH = (Father - 13cm) + Mother / 2 +/- 8cm (range).
What is a height velocity (HV) chart?
This is the measure of a person’s growth over a period of time (6-12 month interval).
How is a HV chart useful?
It differentiates normal variant short stature from pathological short stature.
Where does the normal HV lie?
25-75th percentile.
What is short stature?
It is when you a short. It is a common clinical presentation - a symptom or a variant (NOT a disease). Normal short stature still grows with normal HV.
What is short stature history?
- Mother and fathers heights - MPH.
- Family history of delayed puberty menarche >14 years in females and continued growth after high school in males.
- Look at other siblings child development records.
- Symptoms of underlying illness.
What are the growth disorder categories?
- Normal HV: normal variants:
- familial short stature.
- constitutional delay in growth and development. - Poor height velocity: usually pathological
- proportionate.
- disproportionate.
What is bone age?
XRAY of your hand to give an estimate of your “biological age”. It is taken in approximately 1 year intervals.
What happens if your bone age is higher than your actual age?
You will be short.
What happens if your bone age is lower than your actual age?
You have growth potential.
What are the features of familial short stature?
- Birthweight - normal.
- Chronic illness - absent.
- Family history - yes.
- Infant growth - X centiles.
- Childhood HV - normal.
- Late childhood HV - normal.
- Bone age - same (<1 year from child’s age).
- Puberty - on time.
- Final height - short.
What are the features of constitutional delay in growth and development?
- Birthweight - normal.
- Chronic illness - absent.
- Family history - yes.
- Infant growth - x centiles.
- Childhood HV - normal.
- Late childhood HV - slow.
- Bone age - delayed (>1 year of child’s age).
- Puberty - delay.
- Final height - normal.
What hormones are important for growth?
- ACTH.
- AVP.
- GH.
- TSH.
- Prolactin.
- Oxytocin.
Adrenal glands and gonadal function are very important.
How is growth hormone secreted?
Pulsatile with a low baseline - primarily at night.
What can increase growth hormone secretion?
- Sleep.
- Exercise stress hypoglycaemia.
- Amino acids.
- Malnutrition.
- Sex steroids.
What can decrease growth hormone secretion?
- Obesity.
2. Psycho-social deprivation i.e. children in abusive environments.
What does growth hormone do?
- Inhibits glucose uptake and promotes glycogenolysis (anti-insulin).
- Stimulates protein synthesis.
- Promotes lipolysis.
What is required for normal hepatic production of IGF-1?
Normal insulin levels and good nutrition.
What happens to IGF-1 production with malnutrition?
There is inhibition of IGF-1 production.
What occurs in laron dwarf syndrome?
A person is lacking an IGF-1 receptor. It is an autosomal condition. Basically the person has normal levels of IGF-1, however, there receptor is not working.
Describe IGF binding proteins?
Almost all circulating IGF is bound to IGF binding protein.
IGF-BP-3: binds to IGF-2, most common, GH dependent.
IGF-BP-1: binds to IGF-1, helps to regulate glucose, circadian rhythm.
What is estrogen responsible for in terms of growth?
Epiphyseal maturation.
What happens if there is too much estrogen?
Epiphyseal closure can occur.
What happens if there are no estrogen receptors on epiphyseal plate?
The person will continue to grow.
What happens to growth with hypothyroidism?
There are low levels of T4 (underactive thyroid gland) so the pituitary detects this and will increase TSH levels. It can lead to swelling of the neck/thyroid.
How does T4 effect growth?
T4 has a facilitatory role in growth. It is necessary for GH secretion and for growth plate development and body proportions.
What are proportionate pathological short stature?
- IUGR.
- syndromes.
- Chronic illness.
- Drugs.
- Psychosocial development.
What are disproportionate pathological short stature?
- Syndromes i.e. Turner Syndrome.
- Hypothyroidism.
- Skeletal dysplasia.
