Hyperprolactinemia Flashcards
What is the most common disturbance of the pituitary
Hyperprolactinemia
What is hyperprolactinemia
Elevated serum prolactin (N levels
How many of women presenting with amenorrhea + galactorrhea are hyperprolactinemic
70%
Actions of prolactin
Acts to stimulate breast cell proliferation and induce milk production
Promotes formation of corpus luteum
Suppressed pulsatile secretion of GnRH
Inhibitory for spermatogenesis and steroidogenesis
How is prolactin secretion controlled
Inhibitory effect of dopamine-> D2 receptors on lactotroph cells
+by estrogen, TRH, VIP and oxytocin
Urgent considerations with prolactinoma
May rarely present as pituitary apoplexy
What is pituitary apoplexy, predisposing factors, clinical features and management
Clinical syndrome->infarction or hemorrhage of pituitary adenoma->extends rapidly to compress neighbouring structures
Predisposing: -ve pituitary blood flow, acute +blood flow (diabetes, HTN), +stimulation of gland through +estrogen states or pituitary testing, anticoagulated states
May be asymptomatic or sudden onset of headache, visual loss, nausea and vomiting, cranial nerve palsies, hemiparesis, and impairment of pituitary function.
If extends into Subarachnoid space, can be accompanied by meningism
Can have shock due to secondary adrenal insufficiency
Mx: supportive->fluids, dexamethasone. If conservative doesn’t work->transphenoidal surgical decompression
Red flags
Prolactinoma Acromegaly Hypothalmic mass compressing pituitary stalk MEN1 Chronic renal failure
Overview of differentials
+Pituitary production
Disinhibition by compression of pituitary stalk
Dopamine antagonist
Physiological: Pregnancy (+estrogen, oxytocin) Breast feeding Stress (+TRH) Hypoglycemia, MI, surgery, exercise, sex, sleep
Drugs: Metoclopramide Haloperidol a-methyldopa estrogens MDMA Antipsychotics
Diseases:
Prolactinoma->micro or macro
Stalk damage->pituitary adenoma, surgery, trauma
Hypothalmic disease->craniopharyngoma, tumors
Hypothyroidism (+TRH)
Chronic renal failure (-ve excretion)
Cirrhosis
Most common causes
Prolactinoma Primary hypothyroidism Drug-induced Macroprolactinemia Pregnancy
Presenting features
Amenorrhea
Galactorrhea
Erectile dysfunction
Headaches
Low libido
Weight+
Vaginal dryness
Hypogonadism
Infertility
Osteoporosis
-ve LH/FSH, testosterone and estrogen
Diagnostic approach on detection of +PRL
Detailed history and examination
Exclude physiological causes
Extensive drug history
Examination: VFD, cranial nerve neuropathies Thyroids CRF Cirrhosis Evidence of metabolic abnormalities Pregnancy
Laboratory investigations: LFTs UEC, renal function Thyroid Pregnancy Prothrombin, albumin
Imaging:
MRI->once physiological, drug induced and secondary hyperPRL excluded
If macroadenoma->investigate for hypopituitarism->ACTH, LH, FSH, GH, TSH, free T4, glucose tolerance test, cortisol, testosterone, estradiol, DHEAS, insulin-like growth factor 1
Why doe women experience decreased libido, sexual dysfunction, hirsutism and vaginal dryness, osteoporosis
Hypoestrogenemia
What are the physiological causes to exclude
Pregnancy (+estrogen, oxytocin)
Breast feeding
Stress (+TRH)
Hypoglycemia, MI, surgery, exercise, sex, sleep
Most appropriate time to measure prolactin levels
At least 1 hour after patient has awaken/eaten
How to avoid pulsatile secretion
2-3 samples separated by at least 15-20 minutes
What is the diagnosis when physiological, drug induced and secondary hyperprolactinemias have been excluded and no lesion is detected on MRI
Idiopathic hyperprolactinemia
Management
Treat underlying cause
Dopamine agonist->bromocriptine= -ve PRL secretion, reduction in tumor size and restoration of mestural cycle
(alternative is cabergoline->less SE, more effective, unknown safety in pregnancy, can cause fibrosis)
If intolerant to dopamine agonist therapy->transphenoidal surgery->risk of permanent hormone deficiency and prolactinoma recurrence
Side effects of bromocriptine
Nausea
Depression
Postural hypotension
When is surgery indicated
Visual symptoms
Pressure effects
Failure of medical therapy
Follow up
Monitor prolactin
If headache/visual loss check fields and consider MRI
Medication is decreased after 2 years
Monitor carefully
