Condition- Prolactinoma

Question 1

List two functions of Prolactin

Answer 1

1. Stimulates lactogenesis from the breast
2. Decreases LH secretion from the pituitary = natural contraceptive

Question 2

What are prolactinomas?

Answer 2

• Pituitary adenoma that overproduces prolactin
• Usually microadenomas (<10mm)

Question 3

List some causes of hyperprolactinaemia?

Answer 3

• Physiological: pregnancy, breastfeeding, stress
• Drugs (most common cause): metoclopramide, haloperidol, alpha-methyldopa, oestrogens, ecstasy, antipsychotics
• Disease:
  
  • Prolactinoma (pituitary tumour), craniopharyngioma
  • Stalk damage: pituitary adenoma may compress the stalk reducing dopamine inhibition, or stalk damage from surgery or trauma
  • Hypothyroidism causing high TRH levels

Hypoprolactinaemia is not much of a problem – no physiological consequences

Question 4

List the 4 different types of prolactinomas (classified on size)

Answer 4

• Micoadenomas: <1cm (most common)
• Macroadenomas: >1cm
• Giant Pituitary Adenomas: >4cm
• Malignant Prolactinoma (RARE)

Question 5

With which cancer syndrome is Prolactinoma associated?

Answer 5

MEN1 (Multiple Endocrine Neoplastic Syndrome)

Question 6

Explain how Hyperprolactinaemia causes reproductive symptoms?

Answer 6

• Raised prolactin inhibits LH and FSH (Natural contraceptive)
• This leads to lowered oestrogen and testosterone
• –> Amennorrhea, impotence and loss of libido

Question 7

State one major risk factor for prolactinomas?

Answer 7

Tumour may enlarge during PREGNANCY

Question 8

List some of the signs and symptoms of a prolactinoma in a Woman…

Answer 8

• Amenorrhoea/ oligomenorrhoea
• Galactorrhoea
• Infertility
• Hirsuitism
• Reduced libido
• Weakess (osteoporosis)
• Dry Vagina => dyspareunia
• Headache, visual field loss

Question 9

List some of the presenting symptoms of a prolactinoma in men

Answer 9

• Subtle + gradual onset
• Impotence
• Loss of libido
• Infertility
• Reduced beard growth
• Erectile dysfunction
• Sometimes: Galactorrhoea

Question 10

List some the symptoms (apart from the reproductive ones) that might be experienced by a patient with a macroprolactinoma instead of a microprolactinoma?

Answer 10

• Headache
• Visual field disturbance: if it affects the optic chiasm=> reduced acuity, diploplia, opthalmoplegia, visual field loss, optic atrophy
• Cranial Nerve palsy
• Signs and symptoms of hypopituitarism

Question 11

List some appropriate investigations for prolactinomas…

Answer 11

• Exclude pregnancy
• Bloods:
  
  • TFTs: Hypothyroidism–> high TRH –> increased prolactin release
  • Serum Prolactin levels (high levels (>5000mU/L)= true prolactinoma
• Imaging: MRI pituitary if other causes ruled out

Question 12

What prolactin levels indicate a true prolactinoma? (as opposed to excess TRH causing Prolactin release)

Answer 12

5000mU/L

Question 13

What pharmacological agent can be used to treat prolactinomas?

Answer 13

D2 Agonists (cabergoline and Bromocriptine)

Question 14

List some of the side-effects of Bromocriptine and Cabergoline and which of these is the preferred medication for Prolactinomas?

Answer 14

• Cabergoline is favoured. But bromocriptine used for pregnancy
• Side effects:
  
  • Nausea
  • Depression
  • Postural Hypotension

Question 15

If pharmacological therpay does not treat a prolactinoma what other management procedures could be used?

Answer 15

• Surgery- transphenoidal hypophysectomy
• radiotherapy

Question 16

Describe the prognosis of prolactinomas…

Answer 16

• Spontaneously resolve in 1/3 cases
• D2 agonist withdrawn after 2-3 years but high rates of recurrence