Pituitary 3 Flashcards
5 physiologic functions of PRL (prolactin)
- Milk production
- Steroidogensis in adrenals
- Metabolism of fats/carbs
- Vit D metabolism
- Fetal development
2 main functions of PRL?
- Mammary gland development (puberty)
- Initiation of lactation post-partum (pregnancy)
PRL is secreted by what?
Where are they secreted?
What is the manner?
- Lactotrophs
- Anterior pituitary
- Pulsatile
PRL is inhibited by what??
Prolactin Inhibitory Factor
(Dopamine)
PRL is stimulated by what??
High Thyrotropin Releasing Hormone
PRL is increased by what 2 things?
Smaller increases occur w/ what 6 things?
- CW motion & nipple stimulation
- After sleep
- Exercise
- Intercourse
- Stress
- Pregnancy
- Lactation
PRL suppresses which 3 hormones?
Suppression of this hormone leads to what sxs?
- Gonadotropin Releasing Hormone (GnRH)
- LH and FSH are lowered too as result
- –> altered menses & fertility
PRL stimulates adrenal androgen production leading to what 2 sxs?
- Weight gain
- Hirsuitism (esp women)
What are 4 S/S of Hyperprolactinemia in ONLY women?
◦Irregular menstruation
◦Menopausal symptoms
◦Weight gain
◦Signs of increased androgens (hirsuitism)
What are 2 S/S of Hyperprolactinemia in ONLY men?
◦Impotence
◦Gynecomastia
What are S/S of Hyperprolactinemia in BOTH men/women?
- Infertility
- HA
- Loss of libido
- Peripheral Vision Problems
- Moods changes/ depression
- Galactorrhea
What 2 sxs are indicative of MACROadenoma when PRL levels are elevated?
- HA & Vision Changes
Fasting Serum Prolactin Levels should be measured in ALL pts w/ what 3 sxs?
- galactorrhea
- gynecomastia
- hypogonadism
What does “further work up” for Hyperprolactinemia entail?
MRI (with or without contrast)
What are some causes of Hyperprolactinemia?
}Prolactinoma (autonomous production)
}Other pituitary tumors (GH, ACTH)
}Hypothalamic disease
}Chronic Kidney Failure (decreased clearance by kidneys)
}Cirrhosis or Liver Disease
}Spinal cord damage
}Chest wall injury (such as in herpes zoster or surgery)
}Severe Primary Hypothyroidism (high TRH)
}Anti-psychotic medications
}Radiation, Surgery
}Idiopathic
1st and 2nd MC cause of Pituitary Adenomas?
Least common?
- PRL (40-45%)
- GH (20%)
LC: TSH (1-2%)
What type of PRL level if above 200 is HIGHY suggestive of a PRL secreting adenoma?
Basal (fasting serum) PRL level
What types of adenomas are MC in men vs women?
Women: MICROadenomas
Men: MACROadenomas
(Women are smaller than men)
90% of women w/ hyperprolactinemia have what 3 sxs?
- Amenorrhea
- Glactorrhea
- Infertility
(GIA)
Men c/o what 5 sxs most commonly w/ hyperprolactinemia?
- dec. libido
- HA
- vision changes
- impotence
- infertility
(men need an ID to get HIV checked)
- Medications may cause hyperprolactinemia w/ PRL levels at what range?
- Which drugs? (try to remember 7)
- ≤50-100 ng/mL
- Dopamine-receptor “antagonists” (1st gen. anti-psychotics and Reglan)
Dopamine-”depleting” agents (methyldopa, reserpine)
Others (INH, danazol, tricyclic antidepressants, verapamil, estrogens, antiandrogens, cyproheptadine, opiates, H2-blockers)
Work up for Hyperprolactinemia:
- H&P
- identify autonomous prolactinoma / other etiologies
- Serum assays (which 8?)
- MRI of which 2 structures?
- Visual field exam (if mass suspected)
- Neuro testing (if mass effect suspected)
- Fasting PRL
- FSH
- LH
- Estradiol
- Tesosterone
- TSH
- Renal/Hepatic
- HCG (in females)
- Pituitary & Brain MRI
T/F
- MOST microadenomas DO NOT progress to macroadenomas
True
T/F
- Most macroprolactinomas DO NOT require therapy?
False,
- Dopamine agonists: Bromocriptine twice daily w/ food
- +/- surgical resection
3 tx options for Prolactinemia & Prolactinoma
- Transsphenoidal resection
- Surgical resection
- Radiation therapy
Definition:
- Inability to lactate
Hypoprolactinemia
Hypoprolactinemia
- Lactotrophs are at risk for what 2 things (esp w/ what comorbidity)
Infarction & Necrosis (HTN)
Hypoprolactinemia
- What is post-partum hemorrhage called?
- Pts w/ which comorbidity are more susceptivle to Post-partum pituitary infarction?
- Sheehan’s Syndrome
- Diabetics
What is the Autoimmune Destruction associated w/ Hypoprolactinemia?
- Lymphocytic Hypophysitis
What test is used for Hypoprolactinemia?
What are the results which would be +?
Stimulation test:
◦Administration of TRH (chlorpromazine and others)
◦Rise in PRL levels <200% = Hypoprolactinemia
Functions of ADH
- Synthesized where?
- Secreted by what?
- Increase in serum osmolarity or a decrease in intravascular volume
- Hypothalamus
- Posterior Pituitary Gland
Abnormalities in ADH
- Absent/too little/receptor issues w/ ADH leads to what?
- Too much ADH leads to what?
- Too little: Diabetes Insipidus
- Too much: SIADH
2 types of DI?
- Central / Neurogenic (rare)
- Nephrogenic
MC etiology of Neurogenic/Central DI?
Idiopathic (30%)
2nd MC etiology of Neurogenic/Central DI?
Tumors (25%)
◦Primary (gliomas, craniopharyngiomas)
◦Secondary (lung cancer, breast cancer, leukemia or lymphoma)
◦Pituitary or Hypothalamus
3 lesser common etiologies of Neurogenic/Central DI from greates to least?
- Neurosurgery
- Trauma
- Familial disease (defect in gene that codes for ADH precursor)
MC cause of Nephrogenic DI?
Lithium (20%)
Which 2 etiologies of Nephrogenic DI block the action of ADH?
}Hypercalcemia and/or hypokalemia
Which etiology of Nephrogenic DI?
◦Defective expression of ADH receptors or aquaporin-2
Congenital / Hereditary
3 diseases which cause Nephrogenic DI?
Sickle cell disease,
PCKD,
pyelonephritis
Nephrogenic or Neuro/Central DI?
- relatively common
- Almost all patients: elderly, sick,
Nephro
Both Nephro and Neuro DI have what sxs?
◦*New onset nocturia in the absence of drinking before sleep or prostatic enlargement (in men over age 50)
S/S of DI
- Frequent passage of large volumes of dilute urine
- Excessive/intense thirst (predilection for cold or iced drinks)
- Increased fluid ingestion
- 24 hour urine volumes range from ___ to ___ L
2.5 - 20 L!!!
Clinical Manifestations of DI
- Water balance maintained IF thirst intact & adequate ingestion of fluid
- IF access to water is interrupted, the pt may develop what??
Hypertonic volume depletion:
-
CNS manifestations:
- irritability
- mental dullness
- coma
