Endocrine Flashcards
causes of Cushing’s syndrome
- exogenous steroids: low ACTH, adrenal atrophy
- primary adrenal adenoma: low ACTH, big adrenal w/ c/l atrophy
- ACTH pit adenoma: high ACTH, suppression with dexamethasone
- Ectopic ACTH, (SC lung carcinoma): high ACTH, no suppression
*think carcinoma/ectopic source is a cancer who listens to no one.
what are the ways Cushing’s syndrome produces immunosuppression
dec in phospholipase A2> no arachodonic acid
dec in IL-2> no growth of T cells
dec in histamine> no vasodilation, no increased permeability
Cushing’s presents with moon facies, buffalo hump, truncal obesity (via ____ ____). with HTN and dec K with met alk (via ____).
fat deposits> due to high insulin (via the excess cortisol which has stimulated high glucose)
HTN with met alk> incr a1 receptors on arterioles, making it more sensitive to catecholamines.
pituitary adenoma mass effect
bitemporal hemianopsia= at optic chiasm
types of functional pituitary adenoma
- prolactinoma: produces prolactin (no GnRH, no LH, no FSH)> galactorrhea, 2 amenorrhea in females; dec libido in males. tx: bromocriptine (D2 agonist)
- GH adenoma: produces GH> in kids= gigantism, growth of long bones before epiphyseal plate closes
> in adults, acromegaly. **diagnosed via insulin GF1- produces the symptoms. tx: octreotide (somato anolog) - ACTH adenoma> Cushing’s syndrome. suppressed with dex.
Sheehan syndrome
postpatrum hemm that leads to pit infarct. presents with amennorrhea, difficulty breastfeeding (no prolactin), no pubic hair (no androgens), fatigue
gland grows, but not blood flow.
central diabetes insipidus labs
absent ADH
inc Na, high serum osmolality
dec urine osmolality (highly diluted urine)
*low specific gravity= hyperhydrated urine
water depravation fails to correct osmolality
tx: desmopressin corrects (ADH analog)
nephrogenic diabetes insipidus labs
no response, present ADH (V2R mutation, lithium)
inc Na, high serum osmolality
dec urine osmolality (highly diluted urine)
*low specific gravity= hyperhydrated urine
water depravation fails
desmopressin fails
SIADH labs
excessive ADH= holding onto alot free H2O= diluted serum= “hypotonic hyponatremia”
low Na, low serum osmolality> mental status alter
inc urine osmolality, inc Na urine
tx: free water restriction, demeclocycline (ADH block)
risk: carbamazepine, ecstasy, chloproamide all inc kidney sensitivity to ADH.
Graves Disease labs
inc T4, dec TSH
HYPOcholesteroemia
HYPERglycemia
IgG autoantiboides at TSH receptor (HS II)
thyroid storm
stress/infection> stimulates epi> excesssss T4/T3.
commonly presents as n/v, hypovolemic shock, hyperthermia, arrhythmias.
tx: PTU, B-, steroids. PTU is key to prevent the peripheral conversion of T4 to T3.
thioamide blocks ____
blocks peroxidase (TPO). so prevents organification (thyroglobulin + I2), oxidation of iodine, and coupling to make T3/T4 synthesis.
** so does PTU.
subacute granulomatous de Quervain thyroiditis
presents as tender thyroid
s/p viral infection, makes granuloma inflammtory response
riedel fibrosing thyroiditis
presents as nontender thyroid ~40F
extensive fibrosis & inflame of the thyroid, but not malignant> fibrosis can restrict the airway/local structures
how do you biopsy thyroid
fine needle aspiration.
thyroid is bloody and will not see anything otherwise
how do you differentiate follicular adenoma vs. follicular carcinoma
carcinoma= invasion thru the capsule.
key is that you can’t tell via the fine needle aspiration, need a gross specimen most often.
pathonomic feature of papillary carcinoma
orphan-annie nuclei> papillae are lined by nuclei with white clearing at center.
nuclei grooves> little lines w/in nuclei
psomma bodies> can help, but can be found elsewhere.
*this is most common thyroid cancer
pathonomnic feature of medullary carcinoma
malignant proliferation of parafollicular C cells.
> local amyloidosis stroma
> calcitonin+, they are also neuroendocrine, so perhaps chromogranin+
pathonomnic feature of anaplastic carcinoma
> undifferentitated cells of thyroid of an elderly lady with dysphagia/respiratory compromise.
*often via p53 loss to anaplastic.
21yr M has 1 testis in scrotum. inc FSH, normal LH. what is decr in patient?
inhibin B.
GnRH>FSH/LH release> FSH releases inhibin B
*LH @ leydig> testosterone (neg feedback for GnRH)
the sertoli cells are temp sensitive (incr temp in abdomen)> atrophy from heat damage> low inhibin B> no feedback on FSH> inc FSH.
BUT leydig cells are not as affected by temp> normal LH fxn> normal androgens.
Pt has testicular torsion>u/l orchiectomy. Pt is concerned about sexual dysfxn and infertility. how do they change s/p procedure?
u/l orchiectomy has initial drop in T> + LH secretion> compensatory T production and Leydig hyperplasia in remaining testis> libido, erection, and sexual characteristics normal/unchanged.
loss of inhibin B> inc FSH> + spermatogenesis, but the loss of seminiferous tubules in the u/l testis most pt have decreased net spermatogenesis> reduced fertility.
f/u pt has DM2, on max metformin dose. Pt started on sodium-glucose-cotransporter2 inhibitor. what is the likely additional effect of new med?
decreased BP (lowers intravascular volume, preload reduction, afterload reduction, natriuresis slows glomerular hyperfiltration).
*good for BP, heart failure, diabetic nephropathy
MOA: inhibit PCT absorption of Na and glucose (not one for the other)> giving osmotic diuresis> causing glucosuria> common to get UTIs w/ med
what anti-diabetic med causes fluid retention?
thiazolidinediones= pioglitazone
pit apoplexy> causes loss of ACTH> no cortisol. what kind of shock does this make?
severe hypotension, distributive shock.
tx: glucocorticoids + neurosurgery consult
cabergoline
dopamine agonist (D2+); also bromocriptine
high levels of 17-hydroxyprogesterone indicates
adrenal cortical hyperplasia, specifically 21OH def
17hydroprogesterone–> 11deoxycortisol usually
what is the treatment for 21OH def?
low dose exogenous corticosteroids> will also suppress ACTH> stop the overproduction of androgens
*suppression of LH/Testosterone will help the peripheral conversion of the androgens>feedback on GnRH> but that doesn’t stop the ACTH from leading to more DHEA
insulin> inhibits glucagon. glucagon> stimulates insulin
effects of insulin
inc glucose uptake into cells: muscle, fat, liver
inc glycogen synthesis (store it, prevent glycogenlysis breakdown)
inc protein synthesis in muscle
dec glucagon
dec lipolysis/ketogenesis
congenital adrenal hyperplasia forms:
17a hydroxlyase
21OH hydroxlyase
11OH hydroxlyase
common presentations of them?
starts with the 1: HTN
ends with a 1: female virilization/clitomegaly
17a: impaired sex steroids, cortisol. all aldosterone pathway. HTN & hypokalemia with boys having ambigous genitalia.
21: impaired aldosterone, cortisol. all sex steroids, clitomegaly at birth, hypoBP, hyperkalemia, boys with odor ~3yrs
11: more upstream impairment of cortisol, aldosterone. all sex, but aldo precursor has minimal fxn so will give HTN with virilization
36yr DM1 has recurrent hypoglycemic episodes, difficulty controlling sugars. now at <50mg/dL. Pt has CKD 2/2 with GRF @ 20mL/min. Pt awaiting dialysis. What is the most likely reason for current glycemic disturbances?
dec renal insulin clearance.
declining GFR is unable to filter> unable to degrade insulin>insulin around for longer to push more glucose into cells> hypoglycemic episodes
*originally thought that dec GFR would inc glucose excrete> but in order to get inc excrete would need inc GRF (more filtered, more out), or reach max reabsorb capabilities (DM2). afferent>filter>excrete.
Pt undergoing a total thyroidectomy for papillary carcinoma. During surgery a nearby nerve is injured while ligating the artery running superior and entering the superior portion of the thyroid. What muscle is denervated as a result?
cricothyroid muscle, damage to the superior laryngeal n> leads to dysphonia with changes in pitch/tone
superior thyroid artery> branch of external carotid artery runs with superior laryngral n.
*the recurrent laryngeal n innervates (post, lateral, transverse, oblique cricoarytenoid, thyroartytenoid)> all coming from the 6th phar arch
