Endo 2 - Hypersecretion of APG Hormones

Question 1

What is hyperpituitarism?

Answer 1

Symptoms associated with excess production of APG hormones

Question 2

What can cause hyperpituitarism?

Answer 2

Pituitary tumour

Can also be ectopic (ectopic = non-endocrine tissue)

Question 3

What is hyperpituitarism often associated with?

Answer 3

Visual field defects (& cranial nerve defects)

Question 4

What is the optic chiasm?

Answer 4

The place where the fibres of the nasal retinae cross.

Compression of Optic chiasm = loss of temporal fields of vision

Question 5

Excess ACTH (corticotrophin) can cause?

Answer 5

Cushings disease

Question 6

Excess TSH (thyrotrophin) can cause?

Answer 6

Thyrotoxicosis

Question 7

Excess LH/FSH (gonadotrophins) can cause?

Answer 7

Precocious puberty in children

Question 8

Excess prolactin can cause?

Answer 8

Hyperprolactinaemia

Question 9

Excess GH can cause?

Answer 9

Gigantism (children/teenagers) or acromegaly (adults)

Question 10

Physiological reasons why prolactin may be high?

Answer 10

Pregnancy or breastfeeding

Question 11

Pathological reasons why prolactin may be high?

Answer 11

Prolactinoma (micro adenoma in the pituitary - <10mm)

Question 12

What is the most common functioning pituitary tumour?

Answer 12

Prolactinoma

Question 13

What can high prolactin levels suppress?

Answer 13

High prolactin suppresses GnRH pulsatility - potentially causing secondary hypogonadism

Question 14

How can hyperprolactinaemia present in women?

Answer 14

1. Galactorrhoea (milk production outside of lactation)
2. Secondary amenorrhoea (or oligomenorrhoea)
3. Loss of libido
4. Infertility

Question 15

What is oligomenorrhoea?

Answer 15

Infrequent periods

Question 16

What is secondary amenorrhoea?

Answer 16

When menstruation has started then it switches off

Question 17

How can hyperprolactinaemia present in men?

Answer 17

1. Infertility
2. Erectile dysfunction
3. Loss of libido
4. Galactorrhoea uncommon (men don’t have enough oestrogen usually to prime the breast)

Question 18

What is secreted by the hypothalamus that inhibits prolactin secretion?

Answer 18

Dopamine.

Question 19

How can hyperprolactinaemia be treated?

Answer 19

D2 receptor agonist

Question 20

Usually, pituitary tumours involve neurosurgeons, etc to treat. What is different about a prolactinoma.

Answer 20

Medical treatment is first line. D2 receptor agonists decrease prolactin secretion and reduce tumour size

Question 21

Name 2 D2 receptor agonists.

Answer 21

1. Bromocriptine

2. Cabergoline (1st line D2 receptor agonist - taken 1/2 a week for 3 years)

Question 22

What are the side effects of D2 receptor agonists?

Answer 22

1. Nausea and vomiting (moreso Bromocriptine)
2. Postural hypotension
3. Dyskinesias
4. Depression

Question 23

What is excess GH usually due to?

Answer 23

Benign pituitary adenoma which secretes GH

Question 24

Is acromegaly identified easily?

Answer 24

No.
It can be insidious in onset and also signs and symptoms progress gradually.

Untreated, excess GH can cause increased morbidity and mortaility

Question 25

Excess GH can cause?

Answer 25

CV Disease Respiratory complications Cancer

Question 26

What grows in acromegaly?

Answer 26

1. Periosteal bone 2. Cartilage 3. Fibrous tissue 4. Connective tissue 5. Internal organs (cardiomegaly, splenomegaly, hepatomegaly, etc)

Question 27

What are the clinical features of acromegaly?

Answer 27

1. Excessive sweating 2. Headache 3. General coarseness of features (e.g. nose, hands and feet bigger, lips thicken), enlargement of supraorbital ridges 4. Enlarged tongue 5. Mandible grows (protrusion of lower jaw) 6. Carpal tunnel syndrome (can squash median nerve) 7. Enlarge chest

Question 28

What are the metabolic effects of acromegaly?

Answer 28

Excess GH causes increased endogenous glucose production & decreased muscle uptake. This means increased insulin production which increases insulin resistance - causing impaired glucose tolerance and predisposition to T2DM

Question 29

What are the complications of acromegaly?

Answer 29

1. Increased cancer risk (e.g. colonic cancer - screening done) 2. Obstructive sleep apnoea - bone/soft tissue changes surrounding upper airway causes narrowing/collapse during sleep 3. Hypertension (GH/IGF-1 directly on vascular tree / GH mediated renal sodium absorption) 4. Cardiomyopathy - hypertension, DM, toxic effects of excess GH on myocardium

Question 30

Acromegaly often involves co-secretion of what hormone in addition to GH?

Answer 30

Prolactin. Hyperprolactinaemia will cause secondary hypogonadism

Question 31

What is the gold standard in diagnosing acromegaly?

Answer 31

"paradoxical rise" in GH following oral glucose load (GH should actually decrease)

Question 32

How is acromegaly treated?

Answer 32

1. Surgery (trans-sphenoidal) - FIRST LINE 2. Medical - Somatostatin analogue (e.g. Octreotide) / D2 receptor agonists (e.g. cabergoline) 3. Radiotherapy (can be slow)

Question 33

Somatostatin analogues may cause side-effects in?

Answer 33

The GI system. Nausea, diarrhoea, gallstones may occur