Lecture 23 - 208/2017 Flashcards

1
Q

What does normal growth depend on?

A
  1. Good general health.
  2. Normal nutrition and genetics.
  3. Adequate nutrition.
  4. Caring environment.
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2
Q

What are the causes for abnormal growth?

A
  1. Genetic disorders.
  2. Endocrine disorders.
  3. Cartilage or bone disorders.
  4. General chronic disease.
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3
Q

What are the phases of growth?

A
  1. Infant - rapid growth during the first two years of life (less GH dependent).
  2. Childhood - constant annual growth (GH dependent).
  3. Puberty - rapid growth primarily dependent on sex steroids and increased GH release.
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4
Q

Describe proportion changes in growth?

A

Human beings follow a cephalo-caudal gradient of brith. From birth to puberty the legs grow relatively faster than other post-cranial body parts.

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5
Q

What is the mid-parental height (MPH) range?

A

This is what can determine the potential height of the person.

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6
Q

What is the MPH for a boy?

A

MPH = Father + (Mother +13cm) / 2 +/- 8cm (range)

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7
Q

What is the MPH for a girl?

A

MPH = (Father - 13cm) + Mother / 2 +/- 8cm (range).

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8
Q

What is a height velocity (HV) chart?

A

This is the measure of a person’s growth over a period of time (6-12 month interval).

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9
Q

How is a HV chart useful?

A

It differentiates normal variant short stature from pathological short stature.

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10
Q

Where does the normal HV lie?

A

25-75th percentile.

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11
Q

What is short stature?

A

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.

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12
Q

What is short stature history?

A
  1. Mother and fathers heights - MPH.
  2. Family history of delayed puberty menarche >14 years in females and continued growth after high school in males.
  3. Look at other siblings child development records.
  4. Symptoms of underlying illness.
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13
Q

What are the growth disorder categories?

A
  1. Normal HV: normal variants:
    - familial short stature.
    - constitutional delay in growth and development.
  2. Poor height velocity: usually pathological
    - proportionate.
    - disproportionate.
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14
Q

What is bone age?

A

XRAY of your hand to give an estimate of your “biological age”. It is taken in approximately 1 year intervals.

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15
Q

What happens if your bone age is higher than your actual age?

A

You will be short.

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16
Q

What happens if your bone age is lower than your actual age?

A

You have growth potential.

17
Q

What are the features of familial short stature?

A
  1. Birthweight - normal.
  2. Chronic illness - absent.
  3. Family history - yes.
  4. Infant growth - X centiles.
  5. Childhood HV - normal.
  6. Late childhood HV - normal.
  7. Bone age - same (<1 year from child’s age).
  8. Puberty - on time.
  9. Final height - short.
18
Q

What are the features of constitutional delay in growth and development?

A
  1. Birthweight - normal.
  2. Chronic illness - absent.
  3. Family history - yes.
  4. Infant growth - x centiles.
  5. Childhood HV - normal.
  6. Late childhood HV - slow.
  7. Bone age - delayed (>1 year of child’s age).
  8. Puberty - delay.
  9. Final height - normal.
19
Q

What hormones are important for growth?

A
  1. ACTH.
  2. AVP.
  3. GH.
  4. TSH.
  5. Prolactin.
  6. Oxytocin.

Adrenal glands and gonadal function are very important.

20
Q

How is growth hormone secreted?

A

Pulsatile with a low baseline - primarily at night.

21
Q

What can increase growth hormone secretion?

A
  1. Sleep.
  2. Exercise stress hypoglycaemia.
  3. Amino acids.
  4. Malnutrition.
  5. Sex steroids.
22
Q

What can decrease growth hormone secretion?

A
  1. Obesity.

2. Psycho-social deprivation i.e. children in abusive environments.

23
Q

What does growth hormone do?

A
  1. Inhibits glucose uptake and promotes glycogenolysis (anti-insulin).
  2. Stimulates protein synthesis.
  3. Promotes lipolysis.
24
Q

What is required for normal hepatic production of IGF-1?

A

Normal insulin levels and good nutrition.

25
Q

What happens to IGF-1 production with malnutrition?

A

There is inhibition of IGF-1 production.

26
Q

What occurs in laron dwarf syndrome?

A

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.

27
Q

Describe IGF binding proteins?

A

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.

28
Q

What is estrogen responsible for in terms of growth?

A

Epiphyseal maturation.

29
Q

What happens if there is too much estrogen?

A

Epiphyseal closure can occur.

30
Q

What happens if there are no estrogen receptors on epiphyseal plate?

A

The person will continue to grow.

31
Q

What happens to growth with hypothyroidism?

A

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.

32
Q

How does T4 effect growth?

A

T4 has a facilitatory role in growth. It is necessary for GH secretion and for growth plate development and body proportions.

33
Q

What are proportionate pathological short stature?

A
  1. IUGR.
  2. syndromes.
  3. Chronic illness.
  4. Drugs.
  5. Psychosocial development.
34
Q

What are disproportionate pathological short stature?

A
  1. Syndromes i.e. Turner Syndrome.
  2. Hypothyroidism.
  3. Skeletal dysplasia.