Growth Failure

Question 1

Major categories of causes of growth failure

Answer 1

• nutritional causes
• chromosomal abnormalities
• endocrine causes
• skeletal dysplasias

Question 2

What are some nutritional causes of growth failure

Answer 2

• Undernutrition/malnutrition:
	○ In developing countries
	○ Poverty
	○ Child neglect/abuse 
• Micronutrient deficiencies:
	○ Iron deficiency
	○ Vitamin D deficiency 
• Gut malabsorption: 
	○ Coeliac disease (luminal pathology) 
	○ Cystic fibrosis (pancreatic enzyme deficiency) 
	○ Crohn’s Disease (autoimmune chronic inflammatory bowel disease)

Question 3

What are some endocrine causes of growth failure?

Answer 3

• hypothyroidism, GH deficiency, GCS excess

Question 4

What are some signs of hypothyroidism that are seen in kids, not adults?

Answer 4

Low growth rate, drop in height centiles, bone age delay, absence of fidgeting - sluggish behaviour

Question 5

Common features of GH deficiency

Answer 5

○ Height below 3SD's from mean
○ May have 'baby face' - where eyes, nose and mouth are quite close together i.e. crowding of midface structures
○ Delayed bone age
○ Normal body proportions
○ High pitched voice
○ Increased skinfold thickness
○ Small penis/scrotum
○ GH is glycolytic, so GH deficiency -> increased subcutaneous fat, decreased muscle mass

Question 6

What is the GS test for GH deficiency?

Answer 6

• No “gold standard” test
○ Pituitary MRI will demonstrate underlying congenital lesion or tumour
○ A normal MRI indicates underlying one of many genetic defects leading to GH deficiency
○ Cannot diagnose GH deficiency on a single random serum GH measurement

Question 7

What are some ways you can assess GH deficiency?

Answer 7

○ Physiological stimuli: exercise, sleep
○ Indirect: IGF-1, IGF BP-3
○ Non-physiological stimuli: glucagon, arginine, insulin hypoglycaemia
○ GH secretion

Question 8

Pathologically, how does excess GCS cause growth failure?

Answer 8

• attenuates linear growth by inhibition of chondroblastic growth at the growth plate.

Question 9

What is the hallmark of Cushing’s syndrome?

Answer 9

linear growth attenuation, in contrast to constitutional obesity which is invariably associated with linear growth acceleration

Question 10

What is the hallmark of skeletal dysplasias?

Answer 10

• Dysproportionate short stature

Question 11

What must you note about GH secretion and thus how to do the test?

Answer 11

• Released at night in children

- Episodic - need multiple tests