endocrinology Flashcards
elevated prolactin levels cause amenorrhea because
LH and FSH will decrease
Damage to the pituitary stalk will affect labs how
all levels will decrease except prolactin will increase
prolactin has no stimulatory hormone, it has only
dopamine
hypothyroidism will also cause increased prolactin due to
TRH -thyroid releasing hormone- acts on prolactin and TSH
signs/symptoms of hyperprolactinemia in female
galactorrhea
amenorrhea
infertility
signs/symptoms of hyperprolactinemia in male
impotence
decreased libido
infertility
causes of hyperprolactinemia
hypothalamic dz-sarcoid, pituitary stalk dz,pregnancy, hypothyroid, renal failure, pituitary tumors,cirrhosis, acromegaly, idiopathic, drugs,
drugs assoc with hyperprolactinemia
phenothiazine, metoclopramide,reserpine,methyldopa,, estrogen, opiates,cocaine, TCA, MAO inhib., verapamil, H2 blockers, SSRI’s
prolactin level >150 in nonlactating and nonpregnant, think
prolactinoma
macroadenoma
> 10mm
microadenoma
<10mm
rule out secondary causes hyperprolactinema by
MRI brain
work up suprasellar macroadenoma, infrasellar macroadenomas
visual field testing, eval anterior pituitary function (TSH,ACTH,FSH,LH,IGF1)
infertility or amenorrhea tx with bromocriptine or caberrgoline
if no response to rx, may need surgery
treatment of microadenamas
regular menses-no tx
infertility-bromocriptine
amenorrhea- bromo/cabergoline, OR estrogen/progesterone
most common cause of acromegaly
GH producing tumor of the pituitary
unique sign of acromegaly
enlarging glove and shoe size
S/S acromegaly
enlarging shoe and glove size, widened teeth spacing, incr. soft tissue mass palms/soles, macroglossia, hyperhydrosis, prominent jaw, deep voice, hyperglycemia, arthritis
best screening lab for acromegaly
IGF-1
confirmation of acromegaly diagnosis
failure of growth hormone to suppress <1ug/L within 1-2 hours of 75G oral glucose load
tx of acromegaly
surgery for pituitary adenoma, if no remission after surgery, add somatostatin (octreotide) +/- GH receptor antagonist pegvisomant +/- pituitary irradiation
complications of acromegaly
sleep apnea, carpal tunnel, CHF, LVH, HTN, cardiomegaly, OA, DM, hyperprolactinemia, hypogonadism, visual field defects , giantism
giantism in acromegaly occurs when
GH hyper secretion occurs prior to long bone epiphyseal closure
**Surgery indicated in acromegaly for
pituitary adenomas secreting : ACTH,TSH,GH
adenomas assoc with mass effect, vision field defects or hypopituitarism
prolactinomas unresponsive to dopamine agonists
20 year old presents with impotence, decreased libido, infertility, and anosmia. Lab: decreased testosterone, LH, FSH
Dx & Tx
Kallman’s syndrome-GnRH deficiency
Tx-testosterone
causes of GnRH deficiency
Kallman syndrome, mutation in GnRH receptor gene, hyperprolactinemia
acquired deficiency: long distance runners, anorexia nervosa, starvation, stress
Prolactin levels must be measured in all patients with….
hypogonadism and low LH/FSH
hypopituitarism leads to deficiency of
multiple hormones
hypopituitarism in young children see
growth retardation ( decreased growth hormone)
hypopituitarism in older children see
delayed puberty (decreased LH/FSH)
hypopituitarism in premeopausal see
amenorrhea (decr LH/FSH)
hypopituitarism in men see
hypogonadism (decr libido, infertility, impotence)
hypothyroidism
secondary hypocortisolism
growth hormone deficiency causes
increased fat mass
decreased lean body mass
decreased bone density
decreased quality of life
prolactin deficiency causes
inability to lactate following pregnancy
ACTH deficiency causes
secondary hypocortisolism: hypoglycemis, fatigue, anorexia
thyrotropin deficiency -TSH
wt gain, dry brittle hair, hair loss, dry skin, constipation, fatigue, cold intolerance, cognitive complaints
dx of hypopituitarism
low or inappropriately normal levels of pituitary hormones in the setting of low target hormone ie: low free T4 and normal TSH
initial tests for eval of hypopituitarism
MRI of pituitary
IGF-1,free t4, TSH, am cortisol, ACTH, testosterone, LH, FSH, prolactin
(TSH,LH,FSH may be normal or low in hypopituitarism)
common etiology of hypopituitarism
tumors, brain radiation
hemochromatosis, amyloidosis
sheehan syndrome, empty sella symdrome
lymphocytic hypophysitis
sheehan syndrome
seen after delivery baby, hypotension during labor causes pituitary necrosis
see: failure of lactation, failure to resume regular menses, and fatigue
Empty sell syndrome
decreased pituitary gland volume
10% may have hypopituitarism or increased prolactin
lymphocytic hypophysitis
symmetric and homogeneous sellar mass
usually occurs during or after pregnancy
adrenal insufficiency is common
treatment of hypopituitarism
** cortisol replacement before thyroid replacement
remember stress cortisol dose if ill, stress, surgery
testosterone replacement in males
estrogen/progesterone in females
GH replacement
polyuria, think
central diabetes insipidus
nephrogenic diabetes insipidus
psychogenic polydipsia
with central diabetes insipidus see
> 50% urine osmolality after vasopressin or desmopressin
with psychogenic polydipsia see
hyponatremia
increases urine osmolality after water deprivation
50 y/o male with headache, decreased libido, sparse facial hair, lab:decreased testosterone,LH, and FSH. prolactin 2000. MRI large pituitary adenoma with suprasellar extension. visual exam-bitemporal heminopsia. Dx and Tx
macroadenoma
bromocriptine
in prior pt, if all same except prolactin 50, what dx and tx?
nonsecreting macroadenoma
TX*** nonsecreting large tumors need surgery!!!
same patient but free T4,TSH,am cortisol all decreased, prolactin 2000. Dx & Tx
hypopituitarism
tx: cortisol, thyroid, testosterone if male, bromocriptine
30 y/o female,2mm pituitary adenoma on routine MRI. asymptomatic and menses and prolactin levels are normal. what to do next?
Dx: incidentiloma
Tx: measure IGF-1 and prolactin, if normal, recheck lab and MRI in 6 months
54 y/o male severe headache,nausea, vomiting, hypotension, altered consciousness. MRI show a hemorrhagic mass in the sella.
Dx & Tx
Pituitary Apoplexy (hemorrhage into tumor)
Tx hydrocortisone and surgery
patient to ER after head injury. he is polyuric, elevated BUN, Na 150, urine osmolality of 40.
Dx and how to confirm
central diabetes insipitis
IV desmopressine- should decrease urine volume
38 y/o female with diabetes, amenorrhea, and bronze pigmentation of skin. Lab: neg pregnancy, decreased FT4,TSH,FSH,LH.
Dx and what to do next
dx: hemochromatosis
do iron studies
replace her hormones and thyroid
24 y/o female with polyuria and polydipsia, urine osm is 60 and does NOT change with water deprivation. after vasopressin, osmolality increases to 100. Dx?
central diabetes insipidus
19 y/o female with syncope and has K+ 2.5, HCO3 34, urine K 8
Dx?
dx-bulemia
** #1 cause of metabolic alkalosis in young female- vomiting caues lose of acid from the GI tract
same 19 y/o patient but HCO3 of 20
whats dx now/
laxative abuse, mild acidosis
same 19 y/o but K+ 2.5 and urine K 50
whats diagnosis
diuretic abuse or Barter syndrome (lose K in urine)
most common cause of diabetes insipidus
autoimmune
patient with polyuria and sodium 128, likely cause
psychogenic polydipsia
a few days post op a patient develops Na+ 120. why
pain increases ADH
also use of hypotonic fluids
patient on lithium presents with polyuria
urine osm 50, Na+145
Dx & Tx
lithium induced DI
tx-thiazide or amiloride
** do not stop lithium
patient with thyrotoxicosis and enlarged thyroid
increased: FT4, T3,TSH,RAI
what next
pituitary tumor-do MRI
TSH should be decreased with thyrotoxicosis but since it is increased pituitary is the problem
pt w hashimoto for many yrs now has rapidly enlarging neck mass, engorged neck veins,, hoarseness, dysphagia. ultrasound shows enlarged thyroid and cervical glands. Dx
Primary thyroid lymphoma
high incidence with hashimoto’s
disorders associated with increased risk of thrombosis
prothrombin 20210 mutation ATIII deficiency Protein C deficiency antiphospholipid syndrome resistance to activated protein C
T3 produced by
TSH in pituitary or conversion of T4->T3
conditions that impair peripheral conversion of T4 to T3
systemic illness
malnutrition
old age
drugs:propranolol, PTU, iodine contrast
with impaired conversion of T4 to T3, see
increased rT3
low T3
not used in dx hypothyroidism
low T3 doe not always indicate hypothyroidism
no role in eval of hypothyroidism, so dont measure total T3
only time free T3 us ckecked is eval for
thyroitoxicosis
labs with thyrotoxicosis (hyperthyroid)
^Total T3 &T4, ^ free T3 & T4
decreased TSH
RAI uptake >30%
^except on thyrotoxicosis factitia
hypothyroidism lab
decreased T4 & T3, total and free levels, increased TSH
TPO Ab -thyroid peroxidase antibodies and thyroglobulin antibodies seen in
hashimoto thyroiditis
*presence in euthyroid or subclinical hypothyroidism confer an increased risk of developing overt hypothyroidism
thyroid stimulating immunoglobulin (TSI) seen in
Graves’ disease
TSH binding inhibitor immunoglobulin (TBII)
Graves’ disease or Hashimoto’s thyroiditis
a patient with thyrotoxicosis with enlarged thyroid, incr free T4 and free T3, ^TSH, ^RAI. what test to do next?
do pituitary MRI-pituitary tumor
pt with hashimoto thyroiditis for years presents with rapidly enlg neck mass, engorged neck veins, hoarse, dysphagia.Likely dx
primary thyroid lymphoma-high incident with hashimotos
thyroid binding globulin increased in
pregnancy
estrogen,tamoxifen,methadone
genetic
hepatitis, biliary cirrhosis