Hypersecretion of anterior pituitary hormones

Question 1

What are the signs of GH hypersecretion in adults?

Answer 1

Acromegaly:

• Slow, insidious onset
• Increased growth in periosteal bone, cartilage, fibrous tissue, connective tissue and internal organs (splenomegaly, cardiomegaly, hepatomegaly)
• Prognathism
• Enlarged supraorbital ridges, nose, hands, feet
• Thickening of lips
• Macroglossia
• Barrel chest, kyphosis
• General coarseness of features
• Increased plasma insulin response to oral glucose load
• Increased insulin resistance
• Impaired glucose tolerance test
• DM

Question 2

What are the symptoms of GH hypersecretion in adults?

Answer 2

• Hyperhidrosis
• Headache
• Joint pain
• Carpal tunnel syndrome

Question 3

What are the symptoms of GH hypersecretion in children?

Answer 3

Gigantism:

• Very tall
• Don’t stop growing in late puberty

Question 4

How is acromegaly diagnosed?

Answer 4

• Failed suppression test of GH following oral glucose load (oral glucose tolerance test shows paradoxical rise in GH)
• Elevated serum IGF I

Question 5

How is acromegaly treated?

Answer 5

• Transphenoidal hypophysectomy
• Somatostatin analogues (octreotide) - reduce GH secretion + tumour size
• D2R agonists (cabergoline)
• Radiotherapy

Question 6

What are the individual pituitary hormone excess states that can occur?

Answer 6

ACTH --> Cushing's
TSH --> thyrotoxicosis
LH, FSH --> precocious puberty
Prolactin --> hyperprolactinaemia
GH --> gigantism (children), acromegaly (adults)

Question 7

What are the symptoms of hyperprolactinaemia?

Answer 7

In women:

• Galactorrhoea (milk production)
• Secondary amenorrhoea (or oligomenorrhoea)
• Loss of libido
• Infertility

In men:

• Galactorrhoea uncommon
• Loss of libido
• Impotence
• Infertility

Question 8

How is hyperprolactinaemia diagnosed?

Answer 8

High prolactin + clinical features

MRI to look for pituitary tumour (prolactinoma)

Question 9

How is hyperprolactinaemia treated?

Answer 9

• D2R agonists
• Decrease prolactin secretion, reduce tumour size
• Side effects = n+v, postural hypotension, dyskinesias, depression, pathological gambling

Question 10

What is hyperpituitarism?

Answer 10

Symptoms associated with excess production of adenohypophysial hormones

Question 11

What is the usual cause of hyperpituitarism?

Answer 11

Isolated pituitary tumours

Question 12

What is the common first symptom of pituitary tumours?

Answer 12

Visual field defect - bitemporal hemianopia

Question 13

What is hyperprolactinaemia?

Answer 13

Excess circulating prolactin when not due to a physiological cause, e.g. pregnancy, breast feeding

Question 14

How can excess GH cause diabetes?

Answer 14

Excess GH
Increased endogenous glucose production (liver)
Reduced muscle glucose uptake
Increased insulin production - increased insulin resistance
Impaired glucose tolerance
Diabetes mellitus