Pituitary physiology and disease

Question 1

What hormones are made by what parts of the pituitary gland?

Answer 1

Anterior- FSH/LH, ACTH, TSH, Prolactin, GH Posterior- ADH, oxytocin

Question 2

What are the clinical presentations of pituitary tumours?

Answer 2

Space occupying lesion affect- headache, vision loss. Hormone hypersecretion. Hormone deficiency states. Visual field defects- bilateral hemianopia

Question 3

What is Cushing’s disease?

Answer 3

Excessive anterior pituitary ACTH secretion not to be confused with Cushing’s syndrome. This leads to overproduction of cortisol from the adrenal cortex.

Question 4

What are the signs and symptoms of Cushing’s disease?

Answer 4

Excessive weight, buffalo hump, moonface, abdominal striae, centripetal obesity, glucose intolerance, impotence

Question 5

What test is used to diagnose Cushing’s disease?

Answer 5

Overnight dexamethasone suppression test. Dexamthasone should reduce secretion of corticotrophin from the hypothalamus and ACTH from the anterior pituitary gland. Resulting in a decrease in production of cortisol. High dose dexamethasone should be enough to reduce the cortisol levels in Cushing’s disease. Will do nothing to reduce cortisol in Cushing’s syndrome.

Question 6

What are the signs and symptoms of GH excess?

Answer 6

GH excess leads to acromegaly which presents with: change in appearance, excessive sweating, weight gain, increased hand and foot size, prominent supraorbital ridge, prognathism, interdental separation. thick greasy skin

Question 7

What is the diagnostic test for GH excess?

Answer 7

Oral glucose tolerance test. Glucose should inhibit GH secretion.

Question 8

What impacts do FSH/LH tumours of the pituitary gland have?

Answer 8

Simply space occupying

Question 9

What is the most common pituitary adenoma?

Answer 9

Prolactinoma

Question 10

What are the signs of a prolactinoma?

Answer 10

Hypogonadism, osteoporosis, infertility, oligo/amenorrhea, erectile dysfunction, galactorrhea, reduced facial hair

Question 11

What is the treatment of a prolactinoma?

Answer 11

Dopamine inhibits prolactin and so dopamine agonists can be prescribed

Question 12

What is the arginine test used for?

Answer 12

It is the second line test for GH deficiency. Arginine is administered and a subsequent rise in GH should be noted.

Question 13

What is the clomifene test used for?

Answer 13

To assess gonadotrophin deficiency. Clomifene is a competitive inhibitor of oestrogen binding at the hypothalamus and pituitary, and should therefore trigger LH/FSH release

Question 14

What is the difference between primary and secondary hypopituitarism?

Answer 14

Primary- Issue with pituitary

Secondary- Issue with hypothalamus

Question 15

What is the characteristic sequence of failure in hypopituitarism?

Answer 15

GH-> LH-> FSH-> TSH-> ACTH. PROLACTIN IS RARELY AFFECTED.

Question 16

Give 9 causes of hypopituaritism.

Answer 16

1. Pituitary adenoma
2. Parapituitary tumours
3. Cranial radiotherapy
4. Pituitary infarction- apoplexy, sheehan’s syndrome
5. Infiltration- haemochromatosis, sarcoidosis
6. Empty sella syndrome
7. Infection
8. Trauma
9. Hypothalamic deficiency syndrome (Kallman’s syndrome)

Question 17

What features will be notable in deficiency of the following hormones?

1. GH
2. LH/FSH
3. ACTH
4. TSH
5. Prolactin
6. ADH

Answer 17

1. Short stature in children. In adults- decreased exercise tolerance, decreased muscle mass, depression, increased CVD risk
2. Oligo/amenorrhoea, decreased libido
3. As per secondary hypoaldosteronism
4. Hypothyroidism
5. No lactation
6. Polyuria and polydipsia

Question 18

What are the 3 most important investigations to undertake in hypopituartism?

Answer 18

1. Basal hormone levels
2. Assessing posterior pituitary function
3. MRI + CONTRAST of the pituitary +/- biopsy

Question 19

Does management of hypopituartism usually revolve around replacing the pituitary hormone or its target? What is the important exception to this?

Answer 19

The target hormone

GH

Question 20

What is the management of hypothyroidism due to hypopituartism?

Answer 20

Levothyroxine

Question 21

What is the management of sex hormone deficiency in hypopituartism?

Answer 21

Oetsrogen and testosterone can be administered. Gonadotrophin is required to induce ovulation however.

Question 22

What is the most commonly used steroid in the mangement of ACTH deficiency?

Answer 22

Hydrocortisone TDS

Question 23

What QOL survey is used as criteria in treatment of GH deficiency? What score indicates a requirement to treat?

Answer 23

ADULT GROWTH HORMONE DEFICIENCY ASSESSMENT

>/=11

Question 24

How long does treatment for GH deficiency go on for and how is this divided?

Answer 24

9 months

3 months titration and 6 months therapeutic range

Question 25

What are the investigations for GH deficiency?

Answer 25

Insulin tolerance test is the most widely used test. IV insulin is provided to producea state of hypoglycaemia. This should result in a comcomitant rise in GH.

Measurement of IGF-1. This is non-specific and should not be used to rule out GH deficiency.

Question 26

What is a pituitary apoplexy?

Answer 26

The word apoplexy is defined as a sudden neurologic impairment, usually due to a vascular process. Pituitary apoplexy is characterized by a sudden onset of headache, visual symptoms, altered mental status, and hormonal dysfunction due to acute hemorrhage or infarction of a pituitary gland

Question 27

What is Sheehan’s syndrome?

Answer 27

Sheehan’s syndrome, also known as postpartum pituitary gland necrosis, is hypopituitarism (decreased functioning of the pituitary gland), caused by ischemic necrosis due to blood loss and hypovolemic shock during and after childbirth

Question 28

What are the clinical features of pituitary apoplexy?

Answer 28

Headache (often sudden and severe)
Nausea and vomiting
Diplopia
Changes in vision or visual field
Ptosis

Question 29

What is the management of pituitary apoplexy?

Answer 29

Medical treatment consists of the following:

• Medically stabilize the patient.
• Immediately evaluate electrolytes, glucose, and pituitary hormones.
• Administer high-dose corticosteroids (most patients have hypopituitarism).
• Administer appropriate endocrinologic replacement therapy alone or combined with transsphenoidal surgical decompression of the tumor.
• Avoid the “head down” position, when possible.