Prolactinoma Flashcards
What is a prolactinoma?
Pituitary adenoma (benign lactotroph adenomas) that overproduces prolactin.
Describe the aetiology of prolactinoma
UNKNOWN
99% sporadic
Describe the epidemiology of prolactinomas
Relatively common
Most common type of pituitary adenoma
Higher incidence in premenopausal women
List 5 signs and symptoms of prolactinoma in women
Amenorrhoea/oligomenorrhoea Galactorrhoea Infertility Hirsuitism Reduced libido
List 3 signs and symptoms of prolatinoma in men
Symptoms are subtle + develop slowly
Reduced libido
Reduced beard growth
Erectile dysfunction
Describe the classification of prolactinoma based on size
Microadenomas: < 1 cm
Macroadenomas: > 1 cm
Giant Pituitary Adenomas: > 4 cm
Malignant Prolactinoma (RARE)
List 4 signs and symptoms caused by the size of prolactinoma
Headache
Visual disturbance (bitemporal hemianopia)
Cranial nerve palsies
Signs + symptoms of hypopituitarism
What is the relationship between microprolactinomas and macroprolactinomas?
microprolactinomas rarely expand to become macroprolactinomas
List 4 risk factors for prolactinomas
Female 20-50yrs
Genetic predisposition; MEN-1 mutation
Male 30-60yrs
Oestrogen therapy
List investigations for prolactinoma
Serum prolactin level (extremely high > 5000 mU/L) suggests true prolactinoma
TFTs: hypothyroidism -> high TRH –> stimulates prolactin release
MRI: esp if visual defect is noted
Assessment of pituitary function
What additional investigation should be carried out in women with suspected prolactinoma?
Pregnancy test
What are the goals of treatment of prolactinoma?
Treat cause
Relieve symptoms
Prevent complications
Restore fertility
What drugs are used in treatment of prolactinoma? Why? Give 2 examples
Dopamine Agonists (e.g. cabergoline + bromocriptine) - DOPAMINE IS LIKE THE BRAKE ON PROLACTIN PRODUCTION
Describe the use of dopamine agonists in patients with prolactinoma
Effective in most patients
Cabergoline is used 1st line due to better efficacy + reducing tumour size + better tolerability
Usually need to be continued on a long-term basis
What management approaches are used if medical management is unsuccessful in prolactinomas?
Surgery: transphenoidal hypophysectomy
Radiotherapy: rarely used; only if meds + surgery have failed
List 3 complications of hypogonadism in prolactinoma
Osteoporosis
Reduced fertility
Erectile dysfunction
List 4 complications of tumour size in prolactinoma
Visual loss
Headache
Pituitary apoplexy
CSF rhinorrhoea
What is the prognosis for prolactinomas?
Microprolactinomas spontaneously resolve in ~ 1/3 cases
Dopamine agonist withdrawal is usually attempted after 2-3 years if prolactin levels have normalised + tumour volume is reduced
High rates of recurrence
Describe the physiology of prolactin secretion
Stimulated by: TRH
Inhibited by: Dopamine
Describe the physiological effects of high prolactin
Negative feedback to hypothalamus, increases dopamine release which then decreases prolactin levels.
Decrease secretion of GnRH + thus FSH + LH
