Endocrine Pt. 1 Flashcards
(84 cards)
1
Q
cAMP mechanisms
A
ACTH LH, FSH, TSH ADH (V2 receptor) HCG B1 & B2 receptor a2 receptor Calcitonin PTH Glucagon
2
Q
IP3 mechanisms
A
GnRH TRH GHRH ADH (V1 receptor) Oxytocin a1 receptor Angiotensin II
3
Q
Steroid Hormone mechanisms
A
Glucocorticoids Estrogen Testosterone Progesterone Aldosterone Vit. D Thyroid hormone
4
Q
Activation of tyrosine kinase
A
Insulin
IGF-1
5
Q
cGMP
A
Nitric oxide
atrial natriuretic peptide (ANP)
6
Q
In embryogenesis, _______ is a depression in the roof of the developing mouth in front of the buccopharyngeal membrane that gives rise to the anterior pituitary
A
Rathke’s pouch
7
Q
What 2 hypothalamic nuclei syntheisze posterior pituitary hormones for release into the circulaiton?
A
Supraoptic and paraventricular nuclei
8
Q
Where is the pituitary gland located?
A
Sella turcica of the sphenoid bone
9
Q
Which lobe of the pituitary gland is linked to the hypothalamus by the hypothalamic-hypophysial portal system?
A
Anterior
10
Q
MCC of hypopituitarism
A
Pituitary tumors
11
Q
Anterior pituitary infarct during childbirth d/t post partum hemorrhage
A
Sheehan’s syndrome
12
Q
Clinical features a/w hypopituitarism
A
- Growth failure/ ⬇️ muscle mass in adults (⬇️ GH)
- Adrenal insufficiency (⬇️ ACTH)
- Failure to lactate (⬇️ Prolactin)
- Hypothyroidism (⬇️ TSH)
- Impotence & testicular atrophy in male; amenorrhea & sexual organ atrphy in female (⬇️ FSH/LH)
- Decrease skin & hair pigmentation (⬇️ MSH)
13
Q
Dx & Tx for hypopituitarism
A
Low level of target hormones & MRI;
Hormone replacement
14
Q
Hormones of the anterior pituitary
A
GH, Prolactin, TSH, LH, FSH, ACTH
15
Q
ACTH, MSH, B-lipoprotein & B-endorphin are derived form what single precursor?
A
pro-opiomelanocortin (POMC)
16
Q
Hormones of posterior pituitary
A
ADH & oxytocin
17
Q
GH secretion is increased by?
A
Sleep, stress, puberty, starvation, exercise, & hypoglycemia
18
Q
GH secretion is decreased by?
A
Somatostatin, obesity, hyperglycemia, & pregnancy
19
Q
Actions of GH
A
⬇️ glucose uptake into the cells (diabetogenic)
⬆️ lipolysis
⬆️ protein synthesis, lean body mass, & organ size
⬆️ protein synthesis in chondrocytes and linear growth (puberty growth spurt)
20
Q
Failure to grow, short stature, mild obesity, & delayed puberty.
A
GH deficiency
21
Q
Caused by pituitary adenoma.
Causes enlargement of hand & feet, facial features, & internal organs.
Anti-insulin effect —> HYPERGLYCEMIA
A
GH excess
22
Q
How do you tx GH excess?
A
Somatostatin analogs (Octreotide)
23
Q
Hypersecretion of GH before puberty causes what?
A
Gigantism
24
Q
Hypersecretion of GH after puberty causes what?
A
Acromegaly
25
Why is tunnel visions (bitemporal hemianopia) a/w pituitary adenoma/acromegaly?
Compresses optic chiasm
26
Major hormone responsible for lactogenesis & breast development
Prolactin
27
Prolactin secretion is tonically inhibited by ____ secreted by the hypothalamus and is increased by _____ using negative feedback control
Dopamine (PIF); TRH
28
Prolacitn inhibits ovulation in women by decreasing synthesis and release of _______. How does this affect men?
Gonadotropin-releasing hormone (GnRH) (no FSH/LH); impotence & loss of libido
29
Prolactin excess leads to? Tx?
Glactorrhea & amenorrhea;
| Bromocriptine (dopamine agonist to reduce prolactin secretion)
30
Factors ⬆️ prolactin secretion
```
Estrogen (pregnancy)
Breast feeding
Sleep
Stress
TRH
Dopamine antagonists (antipysch)
```
31
Factors ⬇️ prolactin secretion
Dopamine
Bromocriptine
Somatostatin
32
Where are ADH (vasopressin) & oxytocin synthesized?
In hypothalamic supraoptic & paraventricular nuclei
33
_____ serum osmolarity increases ADH, while _____ serum osmolarity decreases ADH
Increased; Decreased
34
ADH regulates serum osmolarity by ___ H2O reabsorption (aquaporin 2, AQP2) from late distal tubules and collecting ducts via what receptor and mechanism?
⬆️; V2 receptor and cAMP
35
Through what mechanism is ADH a potent vasoconstrictor?
V1 receptor and IP3/Ca mechanism
36
______ is d/t an ADH deficiency. 50% idopathic, the other d/t trauma during neurosurgery
Central Diabetes Insipidus
37
ADH secretion is normal but renal tubules do not respond to ADH. A/w CKD. Sicklers, & drugs (lithium)
Nephrogenic diabetes insipidus
38
What is the Desmopressin challenge test?
⬆️ urine osmolarity after test dose = Central DI;
| No change in urine osmolarity = Nephrogenic DI
39
Tx for Central DI
Desmopressin
| Chlorpropamide (oral hypoglycemic drug) ⬆️ ADH secretion
40
Tx for Nephrogenic DI
Thiazide diuretics (depletes body of Na which leads to ⬆️ reabsorption of Na and Water in PT —> less pee)
41
Overproduction of ADH.
CF: acute hyponatremia (reabsorb too much H2O),
Urine osmolarity > serum osmolarity, signs of brain swelling (lethargy, weakness, seizures, coma, death)
SIADH
42
Tx for SIADH
Remove underlying cause, fluid restriction, demeclocycline (antagonizes ADH on renal tubules), lithium (use for its side effects), 3% NaCl, loop diuretics, non-peptide vasopressin antagonists
43
Causes ejection of milk from breats “let down reflex”.
| Contraction of myoepithelial cells in the breast and contraciton of uterus
Oxytocin
44
Increase oxytocin secretion
Suckling, dilation of cervix, orgasm
45
Oxidation of iodide (I-) to iodine (I2) is catalyzed by ____ enzyme. This enzyme is inhibited by ______?
Peroxidase (PO); propylthiouracil (PTU)
46
Coupling of monoiodotyrosine (MIT) and diodotyrosine (DIT) result in production of?
T4 (thryoxine 93%) and T3 (more potent)
47
In circulation, most of the T4 and T3 is bound to?
Thyroxine-binding globulin (TBG) or thyroglobulin
48
In _____ TBG levels decrease leading to decrease in total T3 and T4 level, but normal levels of free T3 and T4
Hepatic failure
49
In ____ TBG levels increase leading to an increase in total T3 and T4 level, but normall levels of free T3 and T4. Also a normal TSH level
Pregnancy
50
What controls TRH and TSH
Hypothalamic-pituitary
51
IgG type. Release form reticuloendothelial system.
| Bind to TSH receptor on thyroid & act like TSH by stimulating the thyroid to secrete T3 & T4
Thyroid stimulating immunoglobulins
52
Actions of thyroid hormone
1. Thermogenic (⬆️ heat production, BMR, O2 consumption)
2. Growth, bone formation/maturation
3. Maturation of CNS (TH deficiency cause mental retardation)
4. Beta stimulating actions (bblocker for hyperthyroid)
5. ⬆️ CO
6. ⬆️ glucose production & oxidation
7. Catabolic effect on proteins & fats
53
Autoimmune antibodies to TSH receptors (TSI)
Grave’s dz (hyperthyroidism)
54
Autoimmunie thyroiditis or myxedema
Hashimoto’s (hypothyroidism)
55
S/Sx of hyperthryoidism
```
THYROIDISM:
Tremor
Heart rate up
Yawning (fatigability)
Restlessness
Oligomenorrhea & amenorrhea
Intolerance to heat
Diarrhea
Irritability
Sweating
Musle wasting & weight loss
```
56
S/sx of hypothyroidism
```
SLUGGISH:
Sleepiness, fatigue
Loss of memory
Unusually dry skin
Goiter
Gradual personality change
Increase in body weight
Sensitivity to cold
Hair loss, sparseness of hair
```
57
Labs & Tx with hyperthyroidism
⬆️ T3 and T4, ⬇️ TSH;
| Propylthiouracil (PTU), thyroidectomy, radioactive iodine, B blockers
58
Labs and Tx with hypothyroidism
⬇️ T3 and T4, ⬆️ TSH;
| Levothyroxine (T4) replacement
59
Preop hyperthyroidism
No sx until pt is euthyroid.
| PTU, high dose of sodium iodide (⬇️ size of gland and risk of bleeding), bblockers, benzos for sedation
60
Drug of choice intraop for hyperthyroidism? Drugs to avoid?
Drug of choice: thiopental (has anti-thyroid activity in high doses)
Avoid: Ketamine, pancuronium, & indirect acting adrenaergic agonists. (Stimulate SNS and ⬆️ BP & HR). Prone to hepatic injury with halothane
61
Most important threat postop with hyperthyroidism? Tx?
```
Thryoird storm (excessive release of T3 & T4);
Hydration & cooling, BB, PTU, sodium iodide (⬇️ release of TH), cortisol (⬇️ relase, synthesis, & conversion of T4 to T3 (active form))
```
62
Intraop considerations with hypothyroidism
More susceptible to hypotensive effect of anesthetics (⬇️ CO, baroreceptor reflex, IV volume); no change in MAC. May have hypoglycemia, anemia,hyponatremia, difficult intubation d/t large tongue!!, hypothermia
63
Postop considerations with hypothyroidism
Delayed recovery d/t hypothermia, resp depression, & slow drug biotransformation. Prolonged mech ventilaiton. Non-opioids (ketorolac) for postop pain
64
Secretion of adrenocortical hormones by different zones
Zona Glomerulosa - aldosterone
Zona Fasiculata - Cortisol
Zona Reticularis - Androgen
GFR = salt (Na), sugar (glucocorticoids), and sex (androgen)
65
Actions of glucocorticoids (cortisol)
Stimulation of gluconeogensis,
Anti-inflammatory effect (inhibits PG, IL-2, histamine, & serotonin),
Suppression of immune response (IL-2 & T lymophocytes),
Upregulates a1 receptors (⬆️ sensitivy to vasoconstrictor effect)
66
Glucocorticoid secretion is highest at ___ and lowest at _____
8am; midnight
67
Controlled by ACTH byt separately regulated by the renin-angiotensin system
Mineralocorticoids (aldosterone)
68
Actions of mineralocorticoids (aldosterone)
⬆️ renal Na reabsorption “saves Na”
⬆️ renal K secretion “gets rid of K”
⬆️ renal H secretion “gets rid of H”
69
Primary adrenal insufficiency d/t autoimmune destruciton of the adrenal cortex (adrenal crisis)
Addison’s dz
70
S/Sx of Addison’s dz
Hypotension (hyponatremic volume contraction),
⬆️ ACTH (low cortisol stimulates ACTH secreation),
Hypoglycemia, wt loss, weakness, N/V, Hyperpigmentation,
Hyperkalemia/hyponatremia & met acidosis
71
Anesthesia considerations for Addison’s Dz
Steroid coverage during perioperative period
72
How is secondary adrenal insufficiancy different than primary?
Caused by deficiency of ACTH (chronic steroid use casuing atrophy of adrenal cortex);
Does not exhibit hyperpigmentation, volume contraction, hyperkalemia, or met acidosis.
Aldosterone levels are NORMAL
73
Excess of glucocorticoids, (MCC prolonged intake of steroid) vs pituitary adenoma that releases excessive ACTH
Cushing’s syndrome vs Cushing’s disease
74
S/sx of cushings
```
⬆️ cortisol & androgen
⬆️ ACTH if dz, ⬇️ ACTH if prolong steroid use
Hyperglycemia
⬆️protein breakdown/muscle wasting
Central obesity (moon face, buffalo hump)
Poor wound healing
Virilization of women
Na/H20 retention -> HTN
Hypokalemia
```
75
Dexamethasone suppresion test
Normal: 1mg Dex inhibits pituitary & adrenal gland by - feeback > suppression of cortisol
Cushing’s: only with 8mg Dex will pituitary shut off (pituitary adenoma producing too much ACTH)
Adrenal gland tumor: Dex does NOT suppress but there is ⬇️ ACTH
Ectopic ACTH (small cell Ca): Dex does not suppress, but there is ⬆️ ACTH
76
Conn’s Syndrome
Primary hyperaldosteronism d/t aldosterone-secreting tumors.
| HTN, Hypokalemia, Hypernatremia, Met alkalosis, & low plasma renin (- feedback inhibition by high BP & ECF)
77
Caused by CHF. Kidney misperception of low intravascular volume, resulting in an overactive renin-angiotensin system. A/W high plasma renin
Secondary hyperaldosteronism
78
Tx for hyperaldosteronism
Spironolactone (aldosterone antagonist)
79
D/t an enzymatic deficiency in cortisol syntheis.
Congenital Adrenal Hyperplasia (CAH)
80
MC type of CAH.
⬇️ cortisol & aldosterone level (enzyme block);
⬆️ ACTH (by decreased feedback inhibition by cortisol)
⬇️ mineralocorticoids, hypotension, hyperkalemia.
⬆️ 17 a-hydroxyprogesterone (above block) —> ⬆️ adrenal androgens. Ambiguous genitalia in girls + virilization
21 b-hydroxylase defeciency
81
```
Block that ⬇️ cortisol & androgen.
⬆️ aldosterone
Lack of pubic hair,
Hypoglycemia, hypertension, hypokalemia, met alkalosis
⬆️ ACTH
```
17 a-hydroxylase deficiency
82
Anesthetic considerations with cushing’s syndrome
Tend to be volume-overloaded & have hypokalemic met alkalosis.
Supplement K. Osteoporosis = risk of fractures.
⬆️ sensitivity to muscle relaxant.
May need supplemental steroids if syndrome d/t exogenous steroids
83
5 P’s of pheochromocytoma
1. Pressure (paroxysmal HTN)
2. Pain (headache)
3. Perspiration
4. Palpitation
5. Pallor
84
Why should droperidol be avoided in pheochromocytoma?
It inhibits dopamine release & dopamine inhibits release of catecholamines…. No dopamine = lots of catecholamines —> hypertensive crisis
