Growth In Childhood Flashcards
List some things which can be measured in children as a marker of their growth
Head circumference Weight Height/length Leg length BMI Growth velocity
What does cumulative mean?
Plotting something continually over time
What is the equation for height velocity?
Height now - height of last visit / age now - age of last visit
How often is height velocity calculated?
Every 6 months
What is the unit of height velocity?
Cm/yr
Describe the production of the hormone which controls growth
Hypothalamus - GHRH
Anterior pituitary - GH
GH binds to GH receptor in liver and produces IGF-1
Where does IGF-1 act?
Via the IGF-1 receptor on osteoblasts of growth plate/epiphyses of bones
Which cells exist in the growth plate?
Osteoblasts
What kind effect does IGF-1 have on the bones?
Autocrine and paracrine effect
When is the most rapid phase of growth?
Antenatal (in the womb)
Name some important factors for fetal growth
Maternal health
Placenta
IGF-2 (reason for big babies)
Which parent does IGF-2 come from
The father - it’s paternally imprinted
What is important for growth in the first year?
Nutrition!
What is important for growth after the first year?
GH
What are the axes of the growth chart?
Height
Age
If you saw a plateau on an infant’s growth chart, what would it suggest?
GH deficiency
What drives the growth of children between infancy and adolescence?
GH
IGF-1
(Nutrition has less of an impact)
What drives growth at puberty?
Sex steroids
GH
What do the sex steroids do to bones at the end of puberty?
They fuse epiphyseal growth plates
Compare male and female puberty and growth spurt
Girls hit puberty earlier so their growth spurt is earlier than boys
Boys - 13-14cm higher than males
Which bones fuse first at the end of puberty?
Feet>Long bones
Where does the final part of growth occur?
Spine
Which epiphyses are the last to fuse?
The ones in the pelvis
What is most important about where you are on a centile?
The pattern of growth is more important than the position on a centile
What would be a marker of growth abnormality?
If a child falls from a centile position / cross centiles
List the causes of short stature
Genetics IUGR/SGA Endocrine disorders (GH deficiency) Pubertal/growth delay Dysmorphic syndromes (Down's) Chronic paediatric diseases Psychosocial deprivation
List specific endocrine causes of short stature
Hypothyroidism
GH deficiency
Steroid excess
List three genetic causes of growth stature despite having normal growth hormone levels
Turner syndrome
Down syndrome
Skeletal dysplasia
What is important to know before plotting a growth chart?
Birth history Weight Parental heights Medical history Previous measurements
How can you adjust to genetic differences in height?
Work out mid parental centile
List three things about illness which can interfere with growth?
Inflammation, poor nutrition and effects of drugs e.g. steroids can interfere with growth
List some blood tests you’d do if a child seemed to be growing slowly
FBC CRP Serum iron LFT Kidney function tests TFTs Coeliac screen IGF1
List some examinations done if a child appears to be growing slowly
Bone age
MRI of pituitary
Pituitary function testing
List some chronic paediatric diseases which may cause growth abnormalities and explain how these interfere with growth
Asthma Sickle cell Juvenile chronic arthritis IBD (Crohn's, coeliac) CF Renal failure Congenital heart failure
Inflammation interferes with intracellular IGF-1 production
List four causes of tall stature
Excess growth hormone
Marfan syndrome (connective tissue disorder)
Early puberty
Tall parents
List some complications of obesity
T2DM Orthopaedic problems Polycystic ovarian disease CV risk Psychological problems Cancer Respiratory difficulties
Name some syndromes associated with obesity
Cushings
Prader Willi
Lawrence-Moon-Biedl
List some genetic causes of obesity
Leptin deficiency Leptin receptor deficiency POMC deficiency PC-1 deficiency MC4R deficiency
Discuss the Berka hypothesis
The more underweight you are as a child, the most likely you are to become obese as a child
What is the genetics of obesity?
It’s polygenic, highly inheritable
