Tutorial 1

Question 1

Relationship between glucose and growth hormone

Answer 1

Growth hormone works to increase blood sugar. Thus, if glucose is high, GH levels would be low and if glucose is low, GH levels would be high.

Question 2

Why is acromegaly associated with high GH

Answer 2

Because it’s caused by a GH secreting pituitary tumour

Question 3

Why does acromegaly cause thirst

Answer 3

Increase GH will mean blood sugar will be caused to go up. Eventually, this will be above the reabsorptive capacity of the kidneys, so you’ll get sugar being lost in the urine. Osmolarity will increase due to the sugar, which is picked up by osmoreceptors in the hypothalamus and thirst is caused

Question 4

Why could patient with acromegaly get tingling in fingers

Answer 4

Because of compression of the median nerve because the connective tissue of the carpal tunnel expands

Question 5

How does a pituitary tumour affect vision?

Answer 5

Light rays from the periphery are reflected onto the nasal part of the retina. Fibres from the nasal part of the retina cross over at the optic chiasm. The optic chiasm is above the pituitary gland, and can be compressed if there is a pituitary tumour, thus rendering patient effectively blind in peripheral visual field

Question 6

How does a normal person vs person w acromegaly respond to oral glucose tolerance test

Answer 6

usually, increase blood sugar will reduce GH.

In acromegalic patients, the GH stays the same or increases with increasing sugar.

Question 7

Which investigations other than OGTT can be performed

Answer 7

Measure IGF1 (which GH stimulates the release off- you wouldn’t look at GH because it’s pulsatile)

Question 8

Treatment for acromegaly

Answer 8

Brain surgery to take out the tumour
In the mean time, give somatostatin agonists to increase SS which surpresses GH release, dopamine agonists may also help
Radiotherapy