Gigantism

Question 1

What is gigantism?

Answer 1

A rare hormonal disorder in children where there is excess growth hormone.

Question 2

What effects are seen in children with gigantism?

Answer 2

Rapid growth of long bones (humerus and tibia).

Question 3

What glands release what hormones?

Answer 3

Hypothalamus - growth hormone releasing hormone - hypophyseal portal system - anterior pituitary gland - growth hormone.

Question 4

What is the effect of growth hormone?

Answer 4

Causes increased IGF1 (insulin growth factor 1):
promotes cellular metabolism
prevents cell death
stimulates lengthening of long bones.

Question 5

What are the direct effects?

Answer 5

liver - increased glucose release
body - retains nitrogen (muscle growth)
increased insulin resistance
Thickened bones (stimulation of osteoblasts)

Question 6

What are the symptoms?

Answer 6

excessively fast growth and height
rapid weight gain
macrocephaly 
projection of lower jaw
increased size of hands and feet 
increased size of organs 
diabetes
carpal tunnel syndrome
decreased menstruation 
gynaecomastia

Question 7

How is it diagnosed?

Answer 7

MRI - pituitary tumour

Increased IGF-1 (IN spite of a large dose of glucose).

Question 8

What is the treatment?

Answer 8

Surgery
Medication (somatostatin analogues, GH receptor agonists)
Radiation therapy (rarely used due to risks).

Question 9

What is the main cause of gigantism?

Answer 9

The most common cause of too much GH release is a noncancerous (benign) tumor of the pituitary gland