L15 (2): Disorders of Pituitary

Question 1

What is most common cause of dysfunction of pituitary?

Answer 1

Adenoma (non-malignant neoplasm)

Question 2

Even if a pituitary tumour is non-functioning (doesn’t produce hormones) it can still result in inadequete production of hormones- how?

Answer 2

Pressure on surrouding glandular tissue

Question 3

State some symptoms of pressure, on surrounding glandular tissue, from a pituitary tumour

Answer 3

• Nausea/vomitting
• Visual problems (compression of optic chiamsa)
• Headaches

Question 4

State 3 investigations you would do, and why, if you suspect a pituitary adenoma?

Answer 4

• MRI: assess size, anatomy
• Assessment of visual fields
• Blood test or biopsy: is there a hormonal excess or deficiency

Question 5

What is the proper term for tunnel vision? Why may someone get tunnel vision with pituitary tumour?

Answer 5

Bitemporal hemianopia

Pressure on optic chiasma

Question 6

State some common causes of hypopituitarism

Answer 6

• Adenoma
• Radiation therapy
• Inflammatory disease
• Head injury

Question 7

In hypopituitarism there is typically a progressive loss of anterior pituitary function; what hormones are often affected first?

Answer 7

• Growth horomone
• Luteinising hormone

*Note: posterior pituitary not often affected if it is a tumour; inflammatory process may have involvement of posterior

Question 8

Describe what GH deficiency causes in:

• Adults
• Children
• Fetus

Answer 8

• Adults: decreased exercise tolerance, decreased muscle strength, increased body fat, reduced sense of wellbeing
• Children: pituitary dwarfism
• Fetus: jaundice & hypoglycaemia

Question 9

Describe symptoms/signs of gonadotropin deficiency

Answer 9

• Lack of libido
• Infertility
• Impotence (men)
• Oligomenorrhea or ammenorrhea (women)

Question 10

Describe symtoms and signs of ADH deficiency

Answer 10

• Excess dilute urine
• Dehydration
• Polydipsia

= CRANIAL FORM OF DIABETES INSIPIDUS. Causes: hypothalamic tumour, cranial radiotherapy, autoimmune, infections e.g. meningitis

Question 11

Describe symptoms/signs of prolactin excess

Answer 11

• Galactorrhoea (unexplained milk production)
• Gynecomastia (hard breast tissue)
• Hypogonadism
• Ammenorrhoea
• Erectile dysfunction

Question 12

State some causes of hyperprolactinaemia

Answer 12

• Prolactinoma
• Pregnancy
• Suckling
• Stress
• Exercise
• Drug (e.g. antidepressants)

Question 13

How do you treat hyperprolactinaemia?

Answer 13

Cabergoline dopamine receptor agonist

Question 14

Describe signs and symptoms of growth hormone excess

Answer 14

• Headache
• Visual field defects
• Excessive sweating
• Cranial palsises
• Acromegaly in adults (broad nose, thick lips, large extremities, prominent supraorbitla ridge, deepening of voice)
• Gigantism in children
• Diabetes (as GH antagonises actions of insulin)

Question 15

How do you treat excess GH?

Answer 15

• Surgery to remove adenoma (if there)
• Radiation therapy
• Drugs (synthetic somatostain or antagonist of GH receptor)