Pituitary Disorders Flashcards
What part of the pituitary gland synthesizes and secretes hormones?
Anterior pituitary
Does the anterior pituitary respond to negative or positive feedback?
Negative
ACTH comes from what cells?
Corticotrophs
TSH comes from what cells?
Thyrotrophs
LH and DSH comes from what cells?
Gonadotrophs
GH comes from what cells?
Somatorophs
Prolactin comes from what cells?
Lactotrophs
What 6 hormones does the anterior pituitary release?
- ACTH
- TSH
- LH
- FSH
- GH
- Prolactin
What hormones stimulates production and release of cortisol by adrenal cortex?
ACTH
What hormones
stimulates the thyroid to produce T3/T4 → stimulates metabolism of many tissues in the body?
TSH
What hormone triggers ovulation and development of corpus luteum in females?
LH
What hormone stimulates Leydig cell production of testosterone in men?
LH
What hormone stimulates growth of ovarian follicles?
FSH
What hormone stimulates formation of secondary spermatocytes?
FSH
What hormone Stimulates growth, cell reproduction, and cell regeneration?
GH
What hormone stimulates milk production?
Prolactin
What hormone works with LH and testosterone to increase reproductive function
Prolactin
What part of the pituitary only secretes hormones synthesized in the hypothalamus?
Posterior pituitary
What are the 2 hormones of the posterior pituitary?
- ADH
2. Oxytocin
What hormone is released in response to hypertonicity and causes the kidneys to reabsorb solute- free water producing concentrated urine and reduced urine volume?
ADH
What hormone increases uterine contractions?
Oxytocin
What hormone is released via positive feedback loop?
Oxytocin
What hormone promotes stretching of cervix and uterus during labor and stimulates milk release?
Oxytocin
What part of the pituitary synthesizes and secretes MSH?
Intermediate pituitary
What is the most common place to develop brain masses?
Sellar turcica
Visual impairment and diplopia, +/- HA are sx of what?
Sellar mass
What is the most common type of visual impairments associated with a sellar mass due to midline compression/lesion of the optic chiasm?
bitemporal hemianopsia
What is the most common type of benign sellar tumors?
Pituitary adenoma
Other: craniopharyngioma, meningioma, cysts
What is the most common pituitary adenoma?
Prolactinoma (60%)
How are pituitary adenomas generally classifed?
Size and cell of origin from anterior pituitary
Is a microadenoma bigger or smaller than 1 cm?
Smaller (< 1 cm)
Is a macroademona bigger or smaller than 1 cm?
Bigger (> 1 cm)
Are the following benign or malignant causes of sellar masses?
- primary-germ cells tumor
- chordoma
- lymphoma
- metastatic breast or lung cancer
Malignant
When and why would you check the following once a sellar mass has been identified?
- Serum prolactin
- serum IGF-1
- 24-hour urine cortisol, 4. T3/T4/TSH
You would check the following if the mass is symptomatic or causing hormonal abnormalities to determine a treatment plan
30 y/o F presents with amenorrhea, galactorrhea, and concerns of infertility. What disease are you concerned about?
Prolactinoma ( serum prolactin is > 30 ng/mL)
60 y/o F presents with headache and impaired vision. On exam her serum prolactin in > 20 ng/mL. What disease are you concerned about?
Prolactinoma
35 y/o M presents with decreased libido, gynecomastia and concerns of impotence/infertility. What disease are you concerned about?
Prolactinoma (serum prolactin > 20 ng/mL)
Penothiazine, halperidol, benzodiazepines can all cause hyper secretion of what hormone?
Hyperprolactinemia
What 2 meds do you used to treat prolactinoma?
- Cabergoline (prolactin antagonist)
2. Bromocriptine
What is the standard of care for treating prolactinoma?
Transphenoidal resection
What is recommended to do prior to a tansphenoidal resection to make the treatment more effective?
Radiotherapy to shrink the size of the tumor
Acromegaly is a result of an excess of what hormone?
GH
Acromegaly is most commonly caused by what?
Benign pituitary macroadenoma
Serum levels of what hormone are an important marker for excess GH?
IGF-1 (released from the liver)
On exam of 40 y/o M pt you find enlargement of hands, feet, and jaw. What disease are you concerned about?
Acromegaly.
Also will have enlargement of internal organs, specifically the heart
Pts w/ acromegaly are at an increased risk of developing what 3 diseases?
DM, HTN, CAD
When evaluating a pt w/ suspected acromegaly, what lab do you check first?
Serum IGF-1 (if low, no GH excess)
If serum IGF-1 is normal/elevated in pt w/ suspected acromegaly. What test should you order 2nd to help make a dx?
2 hr OGTT
What test is gold standard for dx of acromegaly?
2 hr OGTT
If 2 hr OGTT is preformed on pt w/ suspected acromegaly, what are the expected results?
Failure of GH to decrease (definitive dx)
Is a random serum GH an accurate test for diagnosing acromegaly?
No. Levels fluctuate
What imaging will show a prolactinoma?
MRI
What imaging would you order in pt w/ acromegaly to ID a pituitary tumor?
MRI
What is the medication tx for acromegaly?
Somatostatin analogs (octreotide, lanreotide) → inhibitory and may decrease tumor size
What is surgical tx for a pituitary tumor?
Transsphenoidal microsurgery
When will Transsphenoidal microsurgery be most successful for pt w/ acromegaly? (2)
- GH levels are low
2. Small tumor
What long term follow up is needed in pts with acromegaly?
Measure IGF-1 every 3-6 mos
What is the #1 cause of adult onset GH deficiency?
Pituitary ademona
Sheehan syndrome is a rare disease that will cause what hormonal deficiency?
GH deiciency
Hx of GH deficiency in childhood is a RF for what disease?
Adult onset GH deficiency
A 30 y/o M pt presents with:
↓ Lead body mass & ↑ fat mass
↓ bone mineral density
↓ QoL.
What disease are you concerned for?
Adult onset GH deficiency
What is the tx for GH deficiency if onset in childhood?
GHRT - daily subQ injections
What are the possible SEs of GH therapy? (4)
- peripheral edema
- arthralgia
- paresthesia
- worsening of glucose tolerance (DM risk)
Low T and high FSH/LH levels are diagnostic for primary or secondary hypogonadism?
Primary (hypergonadotropic hypogonadism)
What is the cause in secondary hypogonadism?
Defects in the HPT axis levels
30 y/o M presents w/ hot flashes, ED and decreased libido, muscle mass and body hair. What disease should you be concerned about?
Secondary hypogonadism (hypogonadotropic hypogonadism)
Low T and normal to low FSH/LH levels are diagnostic for primary or secondary hypogonadism?
Secondary
LH/FSH levels are low b/c no feedback loop due to ↓ ant. pituitary
Hx of prostate cancer is a contraindication for what HRT?
Testosterone
What two tests do you need to conduct before starting hypogonadic male on T therapy?
- DRE
2. PSA
What is the initial T regimen for male w/ hypogonadism?
IM injections Q 2 wks
Other: Transdermal patch/cream/gel applied daily
Once T levels are back w/in normal range, how does the tx regimen change for T replacement therapy in male w/ hypogonadism?
Pellets placed subQ Q 3 months
How does testosterone therapy place you at an increased coagulation risk?
T increases RBC production (erythrocytosis)
In addition to lifelong monitoring of free and total T and free estradiol in a M w/ hypogonadism, what tests do you need to preform annually? (2)
DRE
PSA
Global anterior pituitary dysfunction that leads to decreased ant. pituitary hormones is what disease?
Pan-hypopituitarism
What are the two most common causes of pan-hypopituitarism?
- radiation therapy
2. sheehan syndrome
What disease is caused by postpartum pituitary gland necrosis due to blood loss and hypovolemic shock during/ after childbirth?
Sheehan syndrome
What is the most common initial sx of Sheehan syndrome?
Agalactorrhea/difficulties with lactation
Decreased serum levels of ACTH, TSH, LH, FSH, GH, and prolactin are concerning for what disease?
Pan-hypopituitarism
Extensive hormone replacement therapy & Ca + Vit. D supplementation is the tx for what ant. pituitary disease?
Pan-hypopituitarism
What is the most common cause of central diabetes insipidus?
idiopathic
Will ADH levels be high or low w/ CDI?
low
Pt presents to you with polyuria, polydipsia, nocturia/ enuresis. Do you expect them to have concentrated or dilute urine?
Dilute (central diabetes insipidus)
Labs for a pt show:
Hypernatremia (Na > 135)
Serum osmolality = N/↑
Urine osmolality = ↓ (< 250 mOSM/kg)
24 hr urine collection (polyuria > 3L/day)
What disease are you concerned about?
central diabetes insipidus
What is the drug therapy for central diabetes insipidus?
Desmopressin (DDAVP) intranasal
Nephrogenic DI is due a lack of production of ADH or a defect in the kidney’s sensitivity to ADH?
kidney defect (insensitive to ADH)
What is the tx for nephrogenic DI?
- Diuretics (ADH antagonist)
- Low salt/ low protein diet (correct hyponatremia)
An ↑ in release of ADH due to CNS disorders, ectopic ADH by malignancies, drugs, surgery/stress, pain is concerning for what disease?
SIADH
PT presents with N/V and lethargy. Their labs show:
24 hr urine collection = ↓
Serum Na = ↓
Serum osmolality = ↓
Urine osmolality = ↑
What disease are you concerned about?
SIADH
A pt presents w/ hyponatremia, concentrated urine and decreased urine volume. Do you expect their urine osmolality to be increased or decreased?
Increased (SIADH)
What is the TX for SIADH?
fluid restriction (< 800 mL/day)
What physiologic conditions can cause an increase in prolactin? (4)
- Pregnancy
- Breast feeding
- Exercise
- Stress
Will ADH levels be high, low, or normal w/ nephrogenic DI?
Normal