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Flashcards in endocrine Deck (57)
1

thyroid hormone fxn

T4 = 90%, T3 = 10% of production, also calcitoninaffects almost all body tissuesmaintains metab stability by regulating O2 reqs & metabprotein synthesis & catabolism (if x hormone)temp regimpacts CHO metab: enhances epi to stim glycogenolysis & gluconeogenesisaffects lipid metabolism (accelerates degradation of LDL)↑s AV node depol to ↑ HR↑s resp drive, mental alertness, GI motility

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when hypothalamus releases TRH x2

in resp to ↓ circulating T3 & T4cerebral cortex resp to ↓ body T or cold

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TRH & TSH impact

* TRH: anterior pituitary → release TSH * TSH stimulates thyroid to release T3 & T4

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thyroid hormones: secreted most vs active hormone

T4 secreted 90%unbound T3 is most active (90% from T4 deiodination)

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hormone ↑ in primary hypothyroidism

TSH

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hormone ↓ in primary hyperthyroidism

aka Graves DiseaseTSH

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hormone ↑ in primary hyperthyroidism

FT4 (false if on heparin)T4

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hormone ↓ in primary hypothyroidism

FT4T4

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palpable thyroid nodules: mgmt

#1. thyroid fxn tests (TSH, FT4, thyroid antibodies)#2. imaging – US (assess if more than 1 nodule, if it is a cyst or solid)#3. Fine Needle Aspiration bx

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thinning of outer third of eyebrows sign of

hypothyroidism

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primary vs secondary hypothyroidism

primary: gland dysfxnsecondary: pituitary or hypothalamus dysfxn (normal or ↓TSH)

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most common cause of hypothyroidism

Hashimoto's (autoimmune)- evidence of ab to thyroid ags

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Hashimoto's Thyroiditis

transient hyperthyroidism w/ an ↑in antibodies fol↓ed by hypothyroidism

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Graves Disease

autoimmune disease w enlarged thyroid goiterthyroid eye disease (opthalmoptosis)↓TSH↑ T4 or Ft4↑ antithyroglobulin ab, alk phos, thyroid radioactive iodine uptake)hypercalcemia

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hypothyroidism tx

Levothyroxine (Synthroid, Levoxyl)

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Graves Disease tx

- inderal (Propranolol)- thiourea drugs: PTU, methimazole (Tapazole)- radioactive I- surgery

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thiourea drugs

block synthesis of T3 & T4PTU, methimazole (Tapazole)call NP: fever, infection, agranulocytosis (abs neut count lt 500)

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hypothyroidism: monitor & goal

TSH (barometer vs T4 for dx)maintenance dosage levothyroxine 100 - 200 ug/d

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if thyroid replacement too rapid

↑HR, dyspnea, orthopnea, angina, palpitations, nervousness, insomnia

20

thyroid crises + s/s

myxedema or thyroid stormAMS, altered thermal reg, precipitating event/illness

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* myxedema *

Severe HYPOTHYROIDISM- ↓ thyroid fxn + subsequent ↓T3 & T4 → alteration F/E - ↑ capillary permeability, fluid retention- non-pitting edema hands/feet- 50-80% mortality rate d/t hypercapnia & hypoventilation

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* myxedema presenting s/s *

* resp depression, hypotension *stupor, coma, hypothermia

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thyroid storm

Extreme form of HYPERTHYROIDISMMay be brought on by stressful illness or trauma, radioactive iodine, or thyroid surgery↑ mortality rate

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* thyroid storm s/s *

* CV collapse *↑ feverSevere agitationConfusionResp distress if thyroid enlargedVomiting & Diarrhea

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thyroid storm tx

Inderal (monitor carefully: HF)Thiourea Drugs (PTU, Tapazole)HydrocortisoneSodium Iodine (radioactive I) - 1 hr after Thiourea- goal: destroy thyroid parenchyma

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adrenal layers - what secretes what?

outer: aldosteroneinner: cortisol

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cortisol

major glucocorticoid, counters insulin → inhibits insulin secretion, ↑ hepatic gluconeogenesis

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* ↑ skin pigmentation cardinal sign of *

Addison's disease

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Addison's dx

Cosynthropin Stimulation Test → give ACTH (corticotropin) & check serum cortisol levels in 30 & 60 minutes,eval for plasmas cortisol rise, in Addison’s level ↓

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Cosynthropin Stimulation Test

Addison's dx test

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Addison's tx

replacement tx: mineralocorticoidsglucocorticoids- hydrocortisone- prednisone (alternate)- fludrocortisone

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fludrocortisone

for insufficient salt retention during Addison's, stimulates renal tubules to reabsorb Na/excrete K

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adrenal crisis

acute adrenal insufficiencyresult of insufficient cortisol either from insufficient intake or ↑d need

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* adrenal crisis s/s *

* hypotension s/t ↓ vascular tone (shock-like state), hyperpigmentation *HA, confusion, coma, n/v/d, abd pain, fever, dehydration

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addison's + infections

must be tx immediately & vigorously: ↑ hydrocortisone - w major stresses, surgery, trauma, ↑ dose, MediAlert bracelet!

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adrenal crisis mgmt

hydrocortisone IV STAT3L bolus NS or D5NS over 2-3 hrtx precipitating factors & hypoglycemiaone resolved, determine degree of insufficiency - cosynthropin stimulation test

37

Cushing's Sydrome causes x3

exces intake glucocorticoids (Prednisone)if spontaneous (rare):- excess ACTH by pituitary (70%)- lung cancer (SCLC = ectopic source, 15%)- adrenal tumor (15%)

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Cushing's tests x3

screening: 1mg dexamethasone (Decadron) @ 2300 + check serum cortisol @ 080024 hr urine test (cortisol & creatinine; cort/cr gt 95mcg = hypercort)suppression test (further testing)- give decadron, collect urine day 2- urine free cortisol gt 20 = Cushing's

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* the key to Cushing's mgmt *

DETERMINE CAUSE/SOURCE- ACTH normal or ↓: ot pituitary- ACTH ↑ = Cushing's

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Cushing's tx

treat the causetransphenoidal resection if pituitary tumor +/- radunilateral adrenalectomy + hydrocort replacement tx until remaining gland recovers

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ADH

works in tubules: ↑ H2O reabsorptionreleased: serum Na ↑(hyperosmolar) or hypovolemiaunder influence of neural input (CNS) & baroreceptors in the chest

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diabetes insipidus causes

familialpituitary or hypothalamus damagenephrogenic DI (inability of kidney to respond to vasopressin)

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* DI dx *

* 24 hour urine ** vasopressin challenge: desmopressin (IN) = measure UOP & intake *clinical s/sMRI: pituitary tumor

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DI tx

desmopressin (IN, PO, IV)mild: adeq fluid intake

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SIADH s/s

- euvolemic & not osmolality dependent- hyponatremia- serum osm lt 280 mOsm/kg + inappropriate ↑ urine osm gt 900mOsm/kg- no cardiac, liver, lung dz- urine Na gt 20mEq/L- no edema or HTN bc ↑ H2O evenly distributed

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SIADH causes

CNS structural (basilar skull fx) or metabolic disorderSCLC (ectopic source)drug induced: antidepressants (amitriptyline), carbamazepine, haloperidol, chlorproamide

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SIADH tx

drug induced? dcmild-mod H2O intox? restrict fluid 800-1000 mL/daysevere hypoNa + neuro changes: 250 - 500 mL 3% NaCl over 2-4 hr and Lasix- avoid rapid correction d/t risk of demyelination of pons!

48

somogyi phenomenon + mgmt

morning REBOUND hyperglycemia & ketouria responding to NOCTURAL HYPOGLYCEMIA (stims counter-reg hormones)monitor: 3AM glucoses (expect ↓)tx: ↓ insulin qH 10% or + ↑ CHO @ qHS

49

dawn phenomenon + mgmt

AM fasting hyperglycemia, no sx nocturnal hypoglycemia Normal or ↑BG @ qHS blood glucose checkd/t circadian rhythm & release of growth hormone → ↑ BG btw 5 & 8AMtx: ↑qHS insulin 2-3 units

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non-ketotic hyperglycemic hyperosmolar coma: serum osm 310 manifestation

lethargy & confusion

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non-ketotic hyperglycemic hyperosmolar coma: serum osm 320 - 330 manifestation

coma

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non-ketotic hyperglycemic hyperosmolar coma: dx

hyperglycemia 600+serum osm 310+pH 7.3+HCO3 15+anion gap lt 14

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non-ketotic hyperglycemic hyperosmolar coma

partial/relative insulin insufficiency triggering gluconeogenesis but NOT ACIDOSIS= profound volume depletion (6-10 L) resulting in RENAL INSUFFIENCY = ↓ glucose excretion & contrib to ↑BGpoorly recognized until profound volume depletion

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* cornerstone of non-ketotic hyperglycemic hyperosmolar coma therapy *

* FLUID REPLACEMENT! *- hypotn: NS 1-2L first hr- normotn: 0.45% NS 4-6L in 1st 8 hrs- glucose @~250 = D5W or D1/2NSgoals- glucose: 250-300 (↓ risk cerebral edema)- UOP 50cc +monitor for HF esp elderly

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critically ill: target glucose

140 - 180monitor q 30 w 2 hr IV infusions

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non-critically ill: target glucose

fasting lt 140random checks lt 180preferred insulin: scheduled SQ + basal, nutritional, correction components

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basal insulin requirement

0.01 u/kg/hr