Hypothalmic Pituitary Axis

Question 1

What cells make up the anterior pituitary?

• what do they secrete?

Answer 1

Question 2

Hypothalmic pituitary dysfunction?

Answer 2

Question 3

What is the most common form of pituitary tumour?

Answer 3

Prolactinoma

Question 4

Function adenomas of the Pituitary can cause what conditions?

Answer 4

Acromegaly

Cushing’s

Prolactinoma

TSHoma

Question 5

Acromegaly involves excess secretion of what hormone?

Answer 5

GH

Question 6

How does Growth hormone act?

Answer 6

Growth hormone acts on the liver causing release of IGF-1 and IGF-BPI.

IGF-1 stimulates femur and muscle growth.

Stimulates glucose release, can also lead to insulin resistance.

Question 7

What inhibits release of GH?

Answer 7

Somatostatin

Question 8

What causes acromegaly?

Answer 8

Pituitary adenoma of the somatotroph cells.

Note: Is a benign tumour.

Question 9

Multiple endocrine neoplasia type 1 aka Wermer syndrome affects what organs?

Answer 9

Parathyroid

Pancreas

Pituitary

Question 10

Symptoms of acromegaly

Answer 10

Growth of the bones of the hands, feet and lower jaw.

Protrusion of forehead.

Soft tissue swelling in the hands face feet.

Increased size of organs.

Excessive sweating.

These can lead to complications such as:

Carpal tunnel.

Diabetes (diabetogenic effect of GH).

Congestive heart failure (due to heart enlargement).

Gastro intestinal cancers.

Question 11

Cushing’s

Answer 11

Excess ACTH secretion from pituitary leads to excess cortisol release.

Question 12

Symptoms of Cushings

Answer 12

Question 13

High index symptoms of Cushings

Answer 13

Question 14

Diagnosis and Management of Cushing’s

Answer 14

Question 15

What effect does dopamine have on the AP?

Answer 15

Dopamine inhibits release of prolactin.

Question 16

Effects of Prolactin:

Answer 16

• Mammary Gland Development
• Levels increase significantly during pregnancy
• Induce and maintain lactation of the primed breast.
• Lactational Amenorrhea
• Immunomodulatory effectsstimulates lymphocyte growth factor

Question 17

Diagnosis and management of Prolactinoma

Answer 17

Question 18

Non-functioning pituitary adenoma’s include:

Answer 18

Null cell adenomas

Gonadotroph adenomas

Clinically silent adenomas

Question 19

What are NFPA?

Answer 19

• Benign pituitary neoplasms that do not cause hypersecretion of pituitary hormones.
• NFPA is the most common type of pituitary macroadenomas.

Question 20

What is the treatment for NFPA?

Answer 20

Treatment: Observe if static and patients are asymptomatic. Needs surgery if compressive symptoms on the optic chiasm.

Question 21

Hypopituitarism:

Answer 21

Question 22

What is diabetes insipidus?

Answer 22

Diabetes insipidus is a rare condition where you pee a lot and often feel thirsty. Diabetes insipidus is not related to diabetes, but it does share some of the same signs and symptoms. The 2 main symptoms of diabetes insipidus are: extreme thirst (polydipsia) peeing a lot, even at night (polyuria).

Question 23

What is the treatment for diabetes insipidus?

Answer 23

Vasopressin analogues (Desmopressin)

Question 24

Cranial/pituitary Radiotherapy: has what effect on the pituitary?

Answer 24

Hypopituitarism

Question 25

Cranial/pituitary Radiotherapy:

Answer 25

Cranial/pituitary Radiotherapy: * Hypopituitarism can occur up to 10 years after treatment * Late effects of cancer treatment * Observed in childhood cancer survivors * Low dose radiation- primarily GH deficiency and impaired linear growth and precocious puberty I * Higher dose radiation -LH/FSH, TSH and ACTH deficiency

Question 26

Pituitary apoplexy

Answer 26

Haemorrhage and/or infarction of the pituitary gland.

Question 27

What are the symptoms of pituitary apoplexy?

Answer 27

Clinical features * Sudden onset of headache * Vomiting * Visual impairment * Decreased consciousness * Acute hormonal deficiency (ACTH)

Question 28

Lymphocytic hypophysitis

Answer 28

**Autoimmune inflammatory disorder of pituitary.** Lymphocytic hypophysitis (LH) is a condition in which the pituitary gland becomes infiltrated by lymphocytes , resulting in pituitary enlargement and impaired function. It most often occurs in women in late pregnancy or the postpartum period, but can also occur in prepubertal or post-menopausal women, and in men.

Question 29

Lymphocytic hypophysitis symptoms:

Answer 29

Question 30

What is the most common cause hypoprolactinaemia? Other causes?

Answer 30

Sheehan's syndrome - where lactotroph cells die in women due to **postpartum haemorrhage**. Note: Pituitary tumour can damage lactotroph cells due to inflammation. - Note only causes symptoms in pregnant breast feed mothers.

Question 31

Hyperprolactinaemia causes:

Answer 31

Other causes:

Question 32

Symptoms of hyperprolactinaemia in men?

Answer 32

Galactorrhoea / Gynecomastia ED

Question 33

Carpal tunnel syndrome and sleep apnoea are classic complications of what endocrine condition?

Answer 33

Carpal tunnel syndrome and sleep apnoea are classic complications of acromegaly.

Question 34

Acromegaly

Answer 34

Acromegaly is the clinical manifestation of excessive growth hormone (GH). Growth hormone is produced by the anterior pituitary gland.

Question 35

Most common cause of acromegaly

Answer 35

pituitary adenoma

Question 36

Paraneoplastic causes of acromegaly

Answer 36

Rarely, acromegaly can also be secondary to a cancer, such as lung or pancreatic cancer, that secretes ectopic growth hormone releasing hormone (GHRH) or growth hormone.

Question 37

Acromegaly symptoms

Answer 37

**Space Occupying Lesion** * Headaches * Visual field defect (“bitemporal hemianopia”) **Overgrowth of tissues** * Prominent forehead and brow (“frontal bossing”) * Large nose * Large tongue (“macroglossia”) * Large hands and feet * Large protruding jaw (”prognathism”) * Arthritis from imbalanced growth of joints **GH can cause organ dysfunction** * Hypertrophic heart * Hypertension * Type 2 diabetes * Colorectal cancer **Symptoms suggesting active raised growth hormone** * Development of new skin tags * Profuse sweating

Question 38

Investigations for acromegaly

Answer 38

A random growth hormone level is not helpful as it will fluctuate, giving false positives and false negatives **Insulin-like Growth Factor 1 (IGF-1) is the initial screening test (raised)** Oral glucose tolerance test whilst measuring growth hormone (high glucose normally suppresses growth hormone) MRI brain for the pituitary tumour Refer to ophthalmology for formal visual field testing

Question 39

Treatment of acromegaly

Answer 39

Transpehenoidal surgery Pegvisomant (GH antagonist given subcutaneously and daily) Somatostatin analogues to block GH release (e.g. ocreotide) Dopamine agonists to block GH release (e.g. bromocriptine)