Hypersecretion of anterior pituitary hormones

Question 1

What are bromocriptine and cabergoline used for?

Answer 1

They are D2 dopamine receptor agonists which some secretion of prolactin to tackle hyperprolactinaemia.

Question 2

What is excess ACTH/FSH OR LH/TSH/GH called?

Answer 2

Cushing’s disease
Precocious puberty
Thyrotoxicosis
Gigantism (children)-fusion of epophysial growth plates, Acromegaly (adults)

Question 3

What grows in acromegaly?

Answer 3

Periosteal bone
Cartilage
Internal organs (cardiomegaly, splenomegaly, hepatomegaly)
Fibrous tissue
Connective tissue

Question 4

What are some clinical features of acromegaly?

Answer 4

Excessive sweating and headache
Enlargement of supraorbital ridge, nose, hands, feet, lips
Macroglossia (enlarged tongue)
Growth of mandible so lower jaw protrudes (prognathism)
Carpal tunnel syndrome (median nerve compression)
Barrel chest, kyphosis

Question 5

How does acromegaly persist in a predisposition of diabetes?

Answer 5

Excess growth hormone inhibits insulin signalling -> increased insulin resistance -> impaired glucose tolerance -> diabetes mellitus

Question 6

How does acromegaly persist in a predisposition of hypertension?

Answer 6

Direct effects of GH and/or IGF-1 on vascular tree

GH mediated renal sodium reabsorption

Question 7

How would you diagnose acromegaly?

Answer 7

GH is pulsatile, so measurement of this is useless.
Elevated serum IGF-1
Confirm by a failed suppression of GH following oral glucose load (oral glucose tolerance test)

Question 8

How would you treat acromegaly?

Answer 8

• Trans-sphenoidal surgery
• Somatostatin analogues (inhibitory on GnRH) e.g. Octreotide
• Dopamine agonists e.g. cabergoline. The benign pituitary adenoma may cosecrete prolactin.
• Radiotherapy