2: Endocrine - GH deficiency Flashcards
What is the most common cause of growth hormone deficiency
Cranial radiation
What are two primary causes of GH deficiency
- Congenital hypopituitarism
- Idiopathic
What are 4 secondary causes of GH deficiency
- Cranial radiation
- Craniopharyngioma
- TBI
- Psychosocial deprecation
- Infiltration (eg. sarcoidosis)
What is Laron Syndrome
Individual is insensitive to GH, causing high GH and low IGF-1
What is the problem with Laron Syndrome
Individuals are unresponsive to exogenous GH
How does GH deficiency in infancy present
- Prolonged jaundice
- Hypoglycaemia
- Normal growth
Why will GH deficiency in infancy not impact growth
As infants do not depend on GH from growth, use TH and environment
What are features of childhood GH deficiency
Short-stature
Decreased muscle mass - which is replaced with fat causing obesity
How will children with congenital GH deficiency present
- Hypoplasia mid-facial bone
- Frontal bone protrusion
- Delayed dental eruption
- Delayed closure anterior fontanelle
Where is GH released from
Anterior pituitary
Explain GH secretion
GH is released diurnally - majority release happening at night.
What causes negative feedback om GH secretion
GHRH - stimulates GH secretion
GHIH - inhibits GH secretion
When does GH influence growth
Childhood and Adolescence
What is the gold-standard investigation for GH deficiency
Insulin tolerance-test
Explain the insulin tolerance test
Insulin is injected and BG monitored frequently thereafter. Insulin should cause secretion of GH to maintain levels of glucose. Therefore profound hypoglycaemia indicates GH deficiency
