Pituitary, Adrenal, MEN Flashcards
Location of pituitary gland + structures in proximity
Located in sella turcica in sphenoid bone
optic chiasm is anterior
hypothalamus is above
cranial nerves 3, 4, 5, 6 and carotid arteries are close by
What happens when pit tumor compresses optic chiasm?
Bitemporal hemianopsia (can’t see on side in each eye)
Parts of the pituitary gland
Anterior lobe = adenohypophosis
Posterior lobe = neurohypophysis
Hormones of the anterior pit
Makes its own hormones: FSH LH ACTH TSH Prolactin GH All under the control of hypothalamic hormones that travel directly from hypothal thru portal circulation to the anterior pit, which makes the hormones
Hormones of the posterior pit
These are made in the hypothalamus and then transported to the posterior lobe:
vasopressin (ADH)
oxytocin
T/F most prolactin-secreting tumors are not malignant
True
What is the difference between a prolactinoma that is a macroadenoma and one that is a microadenoma
Macro enlarges the pit gland, micro does not enlarge it.
Macro- more common in men
Micro- more common in women
What is the most common pituitary neoplasm?
Prolactinoma
HPE for prolactinoma
Macroadenomas usu cause headache as tumor enlarges.
Women- irreg menses, amenorrhea, galactorrhea
Extraocular mvmt deficits (3,4,6)
Dx Eval for prolactinoma
Serum prolactin >300ug/L = pit adenoma
if >100 it’s suggestive
Use MRI to see micro vs macro
Rx for prolactinoma
Asx w micro- just follow.
If hyperprolactinemia- trial of bromocriptine or cabergoline
If drugs fail- transsphenoidal resection
If macro w compressive sx- bromocriptine (may decrs tumor size) and/or surgical resection.
Resection has high recurrence rates.
Can give radation for long term control but will get pan-hypo-pituitarism
What hormones does GH stimulate?
Stims production of growth-promoting hormones- somatomedin and insulinlike GH
Overproduction of GH leads to…
acromegaly
almost always dt pit adenoma
HPE of GH overproduction
sweating, fatigue, headaches, voice chg, arthralgia, jaw malocclusion, all over many years.
some pts have kidney stones
physEx for acromegaly- bony overgrowth of face/hands, rough features, increased nose, lips, tongue.
LVH and HTN
Dx eval of acromegaly
Serum GH elevated-
GH is NOT suppressed by insulin challenge- give insulin and GH should go down.. but it doesn’t.
Do MRI to see lesion size.
Rx for acromegaly
Resection of tumor, radiation, and/or bromocriptine.
Surgery is better for pts w lower GH levels pre-op
Radiation can cause panhypopituitarism
Bromocriptine is usu not effective by itself
HPE for FSH and LH tumors
Headache/visual field defect from compression.
Tumors can be large, so may get panhypopituitarism.
Women have no hormonal sx. Men with FSH secreting tumors can have lower libido
Rx for FSH and LH tumors
Surgery to relieve compression- they can grow large.
Where are the adrenal glands located?
just above kidneys
anterior to the posterior diaphragm
R gland- lateral and just posterior to IVC
L gland- inferior to stomach, near pancreatic tail
Blood supply to adrenal glands?
Superior supra-adrenal (comes from inferior phrenic artery)
Middle supra-adrenal (comes from aorta)
Inferior supra-adrenal (comes from renal artery)
Venous drainage of adrenal glands?
R adrenal gland- to IVC
L adrenal gland- to renal vein
Structure of adrenal gland, what each part secretes
Cortex and medulla
Cortex- glucocorticoids (cortisol), mineralocorticoids (aldosterone), sex steroids
Medulla- catecholamines (epi, norepi, dopamine)
What is the precursor for glucocorticoids and mineralocorticoids?
Cholesterol- first it is converted to pregnenolone (rate limiting step)
What states stimulate cortisol production?
hypovolemia
hypoxia
hypothermia
hypoglycemia
How is cortisol secreted?
ACTH from the pituitary signals the adrenal cortex. ACTH was controlled by CRF (corticotropin releasing factor) which is secreted from the hypothalamus.
How does cortisol affect insulin and glucagon?
Stimulates glucagon rls
Inhibits insulin rls
What effects do exogenous (given) corticosteroids have?
immune suppression impaired wound healing block inflam cell migration inhibit Ab production inhibit histamine rls inhibit collagen formation inhibit fibroblast fn (all of these are bad for pts that are on steroids for a long time)
How is aldosterone secretion controlled?
By renin-angiotensin system.
decreased renal bld flow or hyponatremia –> JG cells secrete renin
Renin cleaves ang to ang I
Ang I is cleaved to ang II
Ang II causes vasoconstriction and also causes aldosterone rls.
Aldosterone stims the distal tubule to reabs sodium –> increased water retention, restores circulating blood volume, bld prs
What is cushing’s syndrome?
Overproduction of cortisol.
In 80%, it’s dt ACTH hypersecretion.
In 80% of the ACTH hypersecretion pts, it’s dt a pit adenoma (cushing’s dz); other % is from other tumors- smlcc of lung, carcinoid tumors
Sometimes (10-20%), adrenal adenoma is the cause of the cortisol hypersecretion.
HPE of cushing’s
weight gain, easy bruising, lethargy, weakness
appearance: truncal obesity, striae, hirsuitism
HTN, prox musc weakness, impotence/amenorrhea, osteoporosis, glucose intolerance, ankle edema
Dx Eval for cushings
24hr urine collection shows increased cortisol.
If ACTH levels are low- probably dt adrenal problem (bc cortisol suppresses ACTH)
Dexamethasone suppression (of ACTH) test- in pts w pit microadenomas, dexamethasone CAN suppress ACTH production- but only from the pit. so if the source is adrenal or ectopic, it will not be suppressed.
Rx for cushings
remv source of increased cortisol production
pit- resect
adrenal- adrenalectomy if it’s an adenoma; if carcinoma, resect.
What are the causes of hyperaldosteronism?
Adrenal adenoma in 80%
Idiopathic bilateral hyperplasia in 15%
adrenal carcinoma, ectopic production (rare)
HPE for hyperaldosteronism
Usu mild sx- fatigue and nocturia
HTN most common finding
Dx Eval for hyperaldosteronism
Hypokalema- bc sodium is absorbed in the distal tubule preferentially- so there is kaluresis (peeing out potassium)
Aldo lvls in serum and urine are increased
Serum renin is decreased.
CT or MRI to evaluate adrenals- if mass >1cm, probably neoplasm.
Rx for hyperaldosteronism
Surgical excision for adenoma
For carcinoma- excision and/or debulking + chemo.
If idiopathic bilat hyperplasia, give K+ sparing diuretics and dexamethasone.
T/F if an adrenal neoplasm secretes excess sex steroids and virilization occurs, this suggests malignancy.
True- Rx is surgical removal.
What pts are at risk for adrenal insufficiency?
Long-term steroid use.
HPE of adrenal insufficiency
abd pain, vomiting
obtundation, hypotension, hypovolemia, hyperkalemia –> shock, cardiac arrhythmias
If a surgical pt is at risk for adrenal suppression/insufficiency, what should you do?
Perioperative steroids.
Continue after surgery if pt is in critical condition.
MUST id pts before surg!
What is a pheochromocytoma?
Tumor that produces excess catecholamines (epi, ne, dopamine)
HPE for pheochromocytoma
headaches, tachycard, palpitations, anxiety, sweating, chest/abd pain, nausea
Dx eval for pheo
SBP can reach 300mmHg
Urine- elevated epi and ne, also their metabolites are elevated- metanephrine, normetanephrine, VMA.
CT/MRI for tumor location/size
If extra-adrenal tumor- use radioactive meta-iodo-benzyl-guanidine scan.
Rx for pheochromocytoma
Surgical removal- but prep pt first so no HTN crisis-
give Ablockers, then B blockers
Always give alpha first!! to prevent cardiovascular collapse
When should an incidental adrenal mass be excised?
if there is sxtic or biochemical evidence of activity
or if it’s >4cm
What kind of lab workup should you do for an incidental adrenal mass?
24hr urine (for cortisol)
dex suppression test
serum Na, K
serum epi, ne and their metabolites
MEN I
3 Ps:
Parathyroid hyperplasia
Pancreatic islet cell tumors
Anterior pituitary adenomas
MEN IIa
MTC (med thyroid carc)
Pheo
Parathyroid hyperplasia
MEN IIb
MTC
Pheo
mucosal neuromas
+body habitus w thick lips, kyphosis, pectus excavatum
