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Pathophysiology II > The Endocrine System > Flashcards

Flashcards in The Endocrine System Deck (377):
1

What type of communication is used in the endocrine system?

Amplitude modulated signals

2

What determines the strength of the signal in endocrine communication?

The amount of the hormone determines the strength of the signal

3

What type of communication is used in the nervous system?

Frequency modulated signals

4

What determines the strength of the signal in the nervous system?

The frequency of action potentials produced by neurons

5

Why is it that endocrine and nervous systems are thought to be inseparable?

Neurohormones secreted by the nervous system act on endocrine tissues

6

What is the scope of action for the endocrine system?

Broad

7

What is the scope of action for the nervous system?

Precise

8

What is the speed of the endocrine response?

Slow

9

What is the speed of the nervous system response?

Fast

10

Where do autocrine signals act?

On the same cells that secrete them

11

Where do paracrine signals act?

Diffuse locally and act on neighboring cells

12

What types of chemical messengers never enter the blood and only communicate from the interstitial fluid?

Autocrine and Paracrine

13

How do endocrine signals function?

Hormones carried between cells by the blood or other body fluids, bind to specialized receptors on the plasma membrane and induce a response with or without entering the target cell

14

How do neural signals function?

Diffuse a short distance between neurons

15

How do neuroendocrine signals function?

They are released from neurons but act on distant cells

16

What are pheromones?

Hormones released into the environment and act on different individuals

17

What three feedback mechanisms regulate the synthesis and secretion of hormones of the endocrine system?

Neural control
Genetically encoded or acquired biorhythms
Feedback mechanisms

18

What is the most common feedback system used in the body to maintain homeostasis?

Negative Feedback System

19

What is the goal of the negative feedback system?

To have a plasma level of the hormone that feeds back to the hypothalamus to ensure proper levels are maintained

20

What is the mechanism behind a positive feedback system?

The rate of the process increases as the concentration product increases

21

How do protein/peptide hormone receptors function?

The receptor is located on the cell surface of the target cell which triggers a response by activating an intracellular enzyme system generating a second messenger

22

What is the process of signal pathway?

Signal molecule binds to
Receptor protein that activates
Intraceullular signal molecules altering
Target proteins which creates
RESPONSE

23

What is an important aspect of endocrine signaling?

Amplification, the end result is large

24

What are the two most common second messengers?

cAMP & Ca

25

What is the predominant effect of second messengers?

Activate protein kinases

26

What is the general rule of thumb for hormones considered to be peptides or proteins?

All hormones are protein based except those that are secured from the adrenal cortex (steroid hormones)

27

What are considered amine derived hormones?

Tyrosine
Tryptophan

28

What hormones are tyrosine based?

Thyroid hormone
Dopamine
Epinephrine
Norepinephrine

29

What is the tryptophan derived hormone?

Serotonin

30

What is unique about the thyroid hormone storage?

There is no storage in the cell, when ready for release, the molecules move to the edge of the cell for exocytosis into the circulation

31

How do thyroid hormones act like steroids?

Thyroid hormones must be bound to protein in the thyroid follicles

32

What are characteristics of steroid hormones?

All are lipid soluble and derived from cholesterol or have a chemical structure similar to cholesterol

33

What are the steroid hormones?

Cortisol, aldosterone, estrogen, progesterone and testosterone

34

How are steroid hormones stored?

Not stored in discrete secretory granules but are compartmentalized within the endocrine cell and released into the ECF by simple diffusion through the cell membrane

35

Why is the half life of steroid hormone greater than other hormones?

Al steroid hormones (and thyroid) are bound to transport proteins which increase the half life significantly

36

What do steroid hormones take so much more time compared to other hormones?

They travel bound to a protein, once reach the correct cell membrane, diffuse across cytoplasm where is binds with the DNA, induces start of transcription. Many mRNA are produced amplifying the signal

37

What two factors determine hormone clearance?

Rate of secretion into the blood
Rate of removal from the blood

38

How are hormones cleared?

Metabolic destruction by tissues/target cells
Binding with tissues
Excretion into the bile
Excretion by kidneys into the urine

39

How are water soluble hormones broken down?

Degraded by enzymes in the blood

40

What are the two components of receptor modulation?

Up and Down Regulation

41

What occurs during up regulation of receptors?

Due to a lack of stimulation, neural receptors increase in number

42

What occurs during down regulation of receptors?

Due to continuous stimulation of a receptor, neural receptors decrease in number

43

What does the pituitary gland regulate?

Energy and water balance
Growth
Response to stress
Reproduction

44

How many hormones does the pituitary gland secrete?

Eight
Six anterior
Two posterior

45

What does the term trophic indicate?

Act to modulate other endocrine glands, control the function of other tissues

46

Where is the hypothalamus located?

Floor and lateral walls of the third ventricle

47

What is the significance of the hypothalamus?

Area of the brain where the endocrine and ANS work together

48

How is the hypothalamus connected to the pituitary gland?

Pituitary stalk

49

What surrounds the pituitary gland?

Encased in the sella tunica bounded above by the optic chasm and laterally by the cavernous sinuses

50

What regulates the anterior pituitary gland?

Negative feedback via hormones from the target organs in the periphery

51

Where are the four major feedback loops?

GH
TSH
ACTH
LH & FSH ( count as one)

52

What term is used to describe all of the hypothalamic neuropeptides?

Trophic, releasing hormones that go to the anterior pituitary to release hormones

53

What part of the pituitary gland has neural connection?

Posterior pituitary gland has direct neural connection

54

How does the posterior pituitary form?

Downward growth of neural tissues that begins at the diencephalon

55

How does the anterior pituitary gland form?

Up growth of ectodermal tissue that begins as an evagination of an area of the roof of the mouth

56

How do the two glands eventually combine?

As the upgrowth expands, it begins to meet the down growth

57

How does the anterior pituitary gland communicate with the hypothalamus?

Two capillary beds

58

What is the only hormone of the pituitary gland that is not a trophic hormone?

Growth hormone

59

What are tropes?

Cell of the pituitary gland, specifically the anterior, which manufacture and secrete anterior pituitary hormones

60

What is the function of growth hormone?

Skeletal development and body growth, regulates protein and CHO metabolism

61

What is the function of ACTH?

Regulates growth of the adrenal cortex and the release of cortisol and androgenic hormones from the adrenal gland

62

What is the function of TSH?

Controls growth and metabolism of the thyroid gland and the secretion of thyroid hormones

63

What is the function of FSH?

Stimulates ovarian follicle, development/spermatogenesis

64

What is the function of LH?

Induces ovulation and corpus luteum development, stimulates testes to produce testosterone

65

What is the function of prolactin?

Promotes lactogenesis, inhibits synthesis and secretion of LH and FSH

66

How does the thyroid gland get stimulates to release T3 and T4?

Thyrotropin releasing hormone stimulates thyrotroph cells of AP gland --> Thyroid stimulating hormone produces and acts on target tissues at the thyroid gland

67

Where is growth hormones target site?

All tissues

68

What is the most common cause of pituitary pathology?

Adenoma

69

What are the functions of growth hormone?

Sodium retention
Decreased insulin sensitivity
Lipolysis
Protein synthesis
Epiphyseal Growth

70

What is the effect of growth hormone on the liver?

Insulin like growth factor I released

71

What are the functions of insulin like growth factor I?

Insulin like activity
Anti lipolytic activity
Protein synthesis
Epiphyseal growth

72

What is another name for growth hormone inhibiting hormone?

Somatostatin

73

How is growth hormone secreted?

Pulsatile with circadian rhythms

74

What pathophysiology occurs with excess of growth hormone before puberty?

Giantism, response at epiphyseal plates

75

What pathophysiology occurs with excess of growth hormone after puberty?

Acromegaly, the diameter increases

76

What are symptoms typically seen in acromegaly?

Coarsening of facial features, widened fingers, toes, hands and feet, prominent eyebrow ridge and jaws, all organs increase in size

77

What pathology is present when there is a normal amount of GH but there is low or absent ICF1

Pygmies

78

How are GH abnormalities diagnosed?

Random GH elevations (know what point of circadian cycle) High normal GH that fails to suppress with glucose administration
Elevated IGF 1 (this does not undergo daily variation)

79

What airway abnormalities are seen with acromegaly?

Facial deformities, large nose, macroglossia, enlarged thyroid, prognathism, obstructive teeth, hypertrophy of epiglottis, general soft tissue overgrowth and MP 3,4

80

What cardiac abnormalities are seen in acromegaly?

Arrhythmias, CAD and HTN

81

What can be done to a patient with Acromegaly to assess from entrapment neuropathies?

Allen test

82

How can Octreotide be used in the treatment of Acromegaly?

It is a somastatin analog, inhibits GH secretion by binding to somatostatin 2 and 5 receptors

83

What drug is a GH receptor antagonist used for treating Acromegaly?

Pegvisomant

84

What is typically the cause of giantism?

Noncancerous pituitary tumor

85

What symptoms are typically seen in giantism?

Large tongue, coarse body hair, skin thickness, heart failure, weakness and visual problems

86

What is considered dwarfism?

An adult hight of 4'10

87

What are the two main categories of Dwarfism?

Disproportionate and Proportionate

88

What are common characteristics of Achondroplasia?

Average torso, shorter arms and legs, OR short trunk with longer limbs
Large head, protruding jaw, crowded and misaligned teeth, double jointed, spine curves forward

89

How is dwarfism acquired?

Autosomal dominant genetic syndrome

90

What are the characteristics of proportionate dwarfism?

The body parts are in proportion but shortened (GH deficiency after birth)

91

What is the function of ACTH?

Regulates the growth of the adrenal cortex and the release of cortisol and androgenic hormones from the adrenal gland

92

What is one of the most potent activators of the HPA axis?

Surgery

93

When does the largest release of ACTH occur during surgical stimulation?

Reversal of anesthesia, extubation and the immediate post operative period

94

What hormone is released from the adrenal cortex?

Cortisol

95

Based on circadian rhythms, when is the most amount of cortisol released?

In the morning and during stress

96

How can ACTH cause hyper pigmentation?

Possesses mild melanocyte stimulating hormone

97

What is precursor protein that is cleaved to create ACTH?

Pro Opiomelanocortin (POMC)

98

what controls the release of aldosterone?

Renin --> Angiotensin I --> Angiotensin II

99

Where does ACTH act in the body?

Acts on the adrenal cortex to release glucocorticoids (cortisol)

100

What is the process for ACTH to be released?

Hypothalamus --> CRH --> AP --> ACTH

101

What pathology occurs with hyper secretion of ACTH?

Cushing's Syndrome

102

What is typically the cause of Cushing's Syndrome?

Pituitary gland adenoma or over secretion of corticotropin from the hypothalamus

103

Why might ACTH be increased without the presence of Cushing's syndrome?

Adrenal cortex atrophy, cortisol secretion is reduced and does not close the negative feedback loop

104

What can occur when there is hypo secretion of ACTH as a primary pituitary disorder?

Results in decreased cortisol secretion from the adrenal cortex (fatal)

105

What are typically the causes of hypo secretion of ACTH?

Pituitary hyopfunction or failure due to intrapituitary bleed or autoimmune adrenal dysfunction

106

How could an adrenal adenoma causes hypo secretion of ACTH?

Over secretion of cortisol in the negative feedback loop response

107

What two hormones are released from the posterior pituitary gland?

Vasopressin and Oxytocin

108

Where is vasopressin synthesized?

Optic nucleus

109

What are the functions of the two vasopressin receptors?

V1 in blood vessels (high concentration in splenic areas) causes vasoconstriction and increased arterial pressure
V2 in kidneys that cause renal fluid reabsorption and increase blood volume

110

What are additional factors that can cause the release of vasopressin?

At the level of the hypothalamus pain, trauma, nausea, vomiting and increased temperature

111

What pathology can occur when there is an overproduction of ADH?

Syndrome of Inappropriate ADH (SIADH)

112

What are symptoms of SIADH?

Water retention, increased urine osmolality, headache, nausea, vomiting altered LOC and death

113

What is a very serious complication of SIADH?

Water intoxication causing dilutional hyponatremia leading to brain edema

114

What is the treatment for SIADH?

Correct hyponatremia with caution and restrict fluids

115

If profound hyponatremia occurs with SIADH what can be given to prevent deterioration?

Hypertonic 3% saline and IV lasix to correct sodium levels slowly

116

What pathology can occur with underproduction of ADH?

Diabetes Insipidous

117

What are common causes of DI?

Trauma, pituitary tumor, surgery or autoimmune

118

What are symptoms of DI?

Large volumes of dilute urine, dehydration, thirst increased plasma osmolality

119

What is the treatment of DI?

DDAVP a vasopressin analogue

120

What is the function of oxytocin?

Stimulates lactation and is thought to help with social affiliation, infant bonding, trust and love

121

What is the most common cause of hormone pathology?

Anterior pituitary adenoma

122

What are the three most common types of pituitary adenomas?

Prolactin secreting
Growth hormone (acromegaly)
ACTH secreting (cushings)

123

What is the presentation of hypopituitarism?

Decreased thyroid function, depressed glucocorticoid production and suppressed sexual development and reproductive function

124

What are the causes of depletion of pituitary function?

Primary pituitary destruction or destruction of the hypothalamus

125

What can occur if a pituitary adenoma grows upward?

Compresses the optic chasm which leads to visual changes

126

What type of visual changes are seen with compression of optic chasm?

Outer peripheral visual loss (bi temporal hemianopsia)
When severe the patient can only see what is in front of them

127

What is the stalk effect?

Compression of the pituitary stalk may cause elevated prolactin levels and irregular menses

128

What is Sheehan syndrome?

Postpartum pituitary necrosis (enlarged pituitary gland from pregnancy becomes compressed and necrosis occurs)

129

What is pituitary apoplexy?

Occurs when pituitary adenomas suddenly bleed internally leasing to an abrupt in size
The tumor can also outgrow its blood supply leading to swelling and dead tissue

130

What is the treatment of pituitary apoplexy?

Rapid Transphenoidal decompression with consideration of replacement of glucocorticoids and ICP resolution

131

What symptoms are typically seen in Sheehan Syndrome?

Failure to start post part lactation, increased fatigue, cold intolerance and HoTN unresponsive to volume and pressers

132

What are the three layers of the adrenal cortex?

Zona glomerulosa
Zona fasciculata
Zona Reticularis

133

What portion forms the bulk of the adrenal gland?

The adrenal cortex

134

What hormones are secreted from the adrenal cortex?

Secretes Minerocorticoids, Glucocorticoids and Sex hormones

135

What is the function of the adrenal medulla?

SNS mediation, secretes epi and norepi

136

What does the Zona Glomerulosa secrete and what controls its release?

Aldosterone which is controlled by Angiotensin II

137

What is a consequence to the adrenal cortex if there are elevated levels of aldosterone for a prolonged period of time?

Hypertrophy of zona glomerulosa

138

Why are mineralcorticoids the only hormones released from the zona glomerulosa?

They lack an enzyme required from cortisol synthesis

139

What is the largest zone of the adrenal cortex and what does it secrete?

Zona Fasciculata which secretes glucocorticoids (cortisol) and a small amount of sex hormones

140

What is the major controller of cortisol?

ACTH which is released from the anterior pituitary gland

141

What is secreted from the zona reticularis?

Sex hormones and some glucocorticoids which are stimulated by ACTH

142

How is cortisol transported in the blood?

Highly bound to corticosterone binding globulin (CBG)

143

What factors increase CBG production?

Estrogen and pregnancy

144

What factors decrease circulating CBG?

Liver disease and nephrotic syndrome

145

What is the most accurate measure of cortisol activity?

Urinary cortisol

146

What is the plasma half life of cortisol?

80-100 minutes

147

Why is cortisol essential for life?

CHO and protein metabolism
Fatty acid metabolism
Electrolyte and water balance
Anti inflammatory and immunosuppressive actions
Catecholamine synthesis
Normal vascular peremeability

148

How is cortisol released by the adrenal cortex?

Hypothalamus --> CTRH --> Anterior Pituitary --> ACTH --> adrenal cortex --> cortisol

149

What are the target cells for aldosterone?

Epithelial cells in the distal convoluted tubule in the kidney to regulate absorption and potassium secretion

150

What can alter the amount of Aldosterone secreted?

Angiotensin II
ACTH
K
Na

151

Why isn't ACTH the primary stimulus for aldosterone secretion?

ACTH does not appear to be able to stimulate the enzymes unique to the aldosterone pathway very well

152

How does sodium intake affect the activity of aldosterone?

Activity of RAAS inversely related to the dietary Na intake and K stimulates aldosterone secretion

153

What additional factors can cause the release of aldosterone?

ACTH, Na, Dopamine, Beta adrenergic agents

154

What is the function of Aldosterone?

Reabsorption of sodium and secretion of potassium and hydrogen ions contributing to electrolyte and volume homeostasis

155

How is the RAAS activated?

Macula densa cells sense low sodium and chloride concentration
Communicate with the Juxtaglomerular cells which sense low volume and secrete renin
Renin splits angiotensinogen to angiotensin I
ACE found in lungs and kidneys converts angiotensin I to angiotensin II
Angiotensin II binds to receptors that cause mineralocorticoid release

156

What is the rate limiting step in mineralocorticoid and glucocorticoid synthesis?

Cholesterol to pregnenolone

157

How does etomidate affect glucocorticoid production?

It inhibits Beta 17-hydroxyprogesterone conversion to cortisol

158

Why is cortisol a vital mediator of the stress response?

It facilitates catecholamine action and secretion thus helping to maintain CV stability

159

What are the causes of cushing's syndrome?

Endogenous adrenal cortical over secretion OR chronic treatment with glucocorticoids at higher than physiologic doses

160

What is the typical presentation of Cushing;s syndrome?

Moon-faced, tranquil obesity, skinny extremities, thin skin, easy bruising, osteopenia, fluid retention, HTN, hyperglycemia and DM

161

What is the most common cause of Cushing's syndrome?

Administration of glucocorticoids for such conditions as arthritis, asthma and allergies

162

What causes the buffalo hump often seen in Cushing's syndrome?

Redistribution of fat to the back and abdomen

163

What is the goal of treatment in patients with Cushing's syndrome?

Regulating diabetes and hypertension, ensuring intravascular fluid volume and electrolyte concentrations are normal

164

What medication can be given to stop potassium loss and mobilize fluids?

Spironolactone

165

What is a major risk of an open adrenalectomy?

Pneumothorax 20%

166

What drug can be given to patients with Cushing's syndrome if the effects of carcinoma are not cured by surgery?

Mitotaine, an inhibitor of steroid synthesis

167

What is the pathology of primary adrenal insufficiency?

Adrenals are unable to produce sufficient amounts of glucocorticoids, mineralocorticoids and androgen hormones

168

What typically causes Addison's disease?

Autoimmune bilateral adrenal destruction

169

What are symptoms typically seen in Addison's disease?

Fatigue, weakness, anorexia, nausea, vomiting, hyperpigmentation and hypovolemia

170

What electrolyte abnormalities are seen in Addison's disease?

Hyponatremia and Hyperkalemia

171

What causes secondary adrenal insufficiency?

Failure to produce CRH or ACTH caused by HPA disease or suppression

172

What are the causes of secondary adrenal insufficiency?

Most are iatrogenic:
Exogenous glucocorticoid administration
Pituitary surgery or radiation

173

What is the only deficit in secondary AI?

Cortisol is the only deficit, aldosterone is not affected therefore there is no hyper pigmentation and only mild electrolyte imbalances are present

174

What communicable disease is known to cause adrenal insufficiency?

TB

175

What causes adrenal atrophy?

Chronic administration of steroids

176

What does a positive ACTH stimulating test indicate?

Demonstrates a poor response to ACTH and indicates an impairment of the adrenal cortex

177

What is considered absolute adrenal insufficiency?

Low baseline cortisol level and a positive result on the ACTH stimulation test

178

What is considered relative adrenal insufficiency?

Higher baseline cortisol but positive ACTH test

179

What dosage of oral prednisone puts a patient a risk for adrenal insufficiency?

Greater than 20mg/day

180

What dosage of topical or inhaled prednisone puts a patient a risk for adrenal insufficiency?

Greater than 2g/day topical
Greater than 0.8mg/day inhaled

181

What drug has more mineralocorticoid activity?

Hydrocortisone, methylprednisone has less

182

How is glucocorticoid supplementation determined for surgery?

Supplementation is individualized based on the surgery

183

Why is it better to give hydrocortisone compared to methylprednisolone when high doses are required?

Hydrocortisone is less likely to produce fluid retention, edema and hypokalemia

184

What is the glucocorticoid potency and equivalent dose of cortisol?

Potency: 1
Equivalent dose: 20mg

185

What is the glucocorticoid potency and equivalent dose of cortisone?

Potency: 0.8
Equivalent dose: 25mg

186

What is the glucocorticoid potency and equivalent dose of prednisone?

Potency: 4
Equivalent dose: 5mg

187

What is the glucocorticoid potency and equivalent dose of Methylprednisolone?

Potency: 5
Equivalent dose: 4mg

188

What is the glucocorticoid potency and equivalent dose of Triamcinolone?

Potency: 5
Equivalent dose: 4mg

189

What is the glucocorticoid potency and equivalent dose of Betamethasone?

Potency: 25
Equivalent dose: 0.6mg

190

What is the glucocorticoid potency and equivalent dose of Dexamethasone?

Potency: 30
Equivalent dose: 0.75

191

What type of patients are at risk for adrenal insufficiency?

Systematic inflammation: TB, HIV, DIC
Sepsis
Etomidate for sedation
Hemodynamic instability

192

How does Conn's syndrome occur?

Functional tumor that acts independently of a physiologic stimulus

193

What conditions can Conn's syndrome be associated with?

Pheochromocytoma
Primary hyperparathyroisism
Acromegaly

194

What is the cause of secondary hyperaldosteronism?

Increased circulating renin which stimulates aldosterone release (renovascular hypertension)

195

What is the primary difference in diagnosing primary versus secondary hyperaldosteronism?

In primary there is suppressed plasma renin activity and in secondary there is elevated plasma renin activity

196

What are symptoms associated with both primary and secondary hyperaldosteronism?

Spontaneous hypokalemia, systemic hypertension, polyuria, metabolic alkalosis and muscle weakness

197

What syndrome can mimic hyperaldosteronism?

Licorice syndrome, due to long term licorice ingestion

198

What is the immediate treatment for primary hyperalsosteronism?

Potassium replacement, administer spironolactone to block aldosterone effect
Potassium sparing and antihypertensive

199

What are some anesthetic considerations for primary hyperaldosteronsim?

Avoid Sevo if hypokalemic neuropathy and polyuria are present
Hypokalemia may modify response to NDNMBA
Avoid hypoventilation and worsening hypokalemia
Be cautious to over correct volume status, HoTN effects of CV drugs may be magnified

200

What is another metabolic disturbance seen in hyperaldosteronism?

Hyperglycemia

201

What does isolated hypoaldosteronism describe?

Lowered aldosterone without corresponding changes in cortisol

202

What is typically the cause of isolated hypoaldosteronism?

Due to renin or angiotensin II regulation issues (hyporeninemia)
Can be congenital
NSAID induced

203

What are the symptoms of hypoaldosteronism?

Hyperkalemia, acidosis, sodium loss, cardiac conduction defects, volume depletion and HoTN

204

What is the treatment for hypoaldosteronism?

Mineralocorticoids and glucocorticoids if cortisol deficiency is present

205

What are the hormones of the adrenal medulla?

Epinephrine, Norepinephrine and Dopamine

206

What are the physiologic effects of Epinephrine?

Promotes energy mobilization, glycogen converted to glucose, fat to fatty acids
CV changes
Shunts blood from gut/skin to muscles and bronchodilation

207

What are the physiologic effects of Norepinephrine?

Neurotransmitter of the sympathetic division of the ANS

208

What is the breakdown of epi to norepi release from the adrenal medulla?

Epi 80%
Norepi 20%

209

What type of cells produce the adrenal medulla hormones?

Chromaffin cells principle site where tyrosine is converted to catecholamines

210

Where do pheochromocytomas arise?

In the chromaffin cells of the adrenal medulla

211

What is the typical breakdown of catecholamines released when a pheochromocytoma is present?

Norepi: 85%
Epi: 15%

212

Where is the most common extra-adrenal location for a pheochromocytoma?

Organ of Zuckerkandl, near the aortic bifurcation

213

What are the rules of 10s when speaking about pheochromocytomas?

10% Found in children
10% are bilateral
10% are malignant
10% are extra-adrenal

214

What are the three most common symptoms of pheochromocytoma?

Palpitations
Headaches
Episodic sweating

215

What are the hyperadrenergic symptoms of a pheochromocytoma?

Pressure (elevated BP)
Pain
Perspiation
Palpitations
Pallor

216

What are patients hyperglycemic with a pheochromocytoma?

Secondary to catecholamine glycohenolysis and insuline release inhibition

217

What are additional symptoms seen with pheochromocytoma?

Cardiomyopathy
Anxiety
Weight loss

218

What is the most sensitive test for high risk patients if a pheochromocytoma is suspected?

Measurement of plasma free metanephrines

219

If there is a low probability of pheochromocytoma, what test is done?

Urinary vanillylmandelic acid (VMA) which is a breakdown byproduct of norepinephrine and plasma catecholamines

220

What are byproducts of catecholamines?

Metanephrines

221

What test is used to determine if a pheochromocytoma is present if the VMA and Metanephrine tests are inconclusive?

Clonidine suppression test

222

What is the best indicator for a pheochromocytoma?

CT scan

223

What is the result if a pheo is present in a clonidine suppression test?

There will be no change in catecholamine levels after Clonidine is given, if no pheo catecholamine level is lower

224

What is the first line treatment for pheochromocytoma?

Alpha blockade

225

What medication is used most frequently in preoperative pheochromocytoma?

Phenoxybenzamine, a long acting non competitive alpha 1 antagonist

226

Which alpha antagonist is easier to titrate in the treatment of a pheo?

Prazosin, pure alpha 1 competitive blocker

227

What drug is used in the treatment of a pheo to decrease catecholamine production?

Metyrosine

228

What are the treatment goals for a pheo?

Normotensive, resolution of symptoms and elimination of any EKG changes

229

What can occur if you over treat a pheo?

Severe orthostatic hypotension

230

What is the rule of thumb for giving both alpha and beta antagonists in treating a pheo?

ALWAYS give alpha before beta, if you give beta first the patient will have to eject against massive SVR sending patient into heart failure

231

What drugs should be avoided in pheo surgery?

Histamine releasing drugs and Vasolytics

232

What actions can induce the release of catecholamines that should be avoided for surgical removal of a pheo?

Fear, pain, shivering, hypercarbia and hypoxia

233

What is the antihypertensive drug of choice when removing a pheo?

Nitroprusside because it does not act on alpha at all it is a direct smooth muscle relaxant

234

What drug is preferred for intraoperative HTN in a epi secreting tumor?

Labetalol has beta blocking properties

235

How can a patient become hypoglycemia intraperatively while removing a pheo?

Decreased catecholamine levels leave insulin unopposed, dextrose containing fluids should be given after tumor removal

236

What can cause hypertensive episodes when removing a pheo?

Tumor manipulation

237

What can cause hypotensive episodes when removing a pheo?

Removal, alpha blockade is unmasked

238

What is Diabetes Mellitus?

A heterogeneous group of disorders that have the common feature of a relative or absolute lack of insulin

239

What is the pathology of Type I DM?

Associated with T cell mediated autoimmune diseases
There is an insulin deficiency that makes the patient susceptable to ketoacidosis

240

What is the pathology of Type II DM?

Not immune mediated, susceptible to hyperosmotic non ketotic coma if insulin is deficient

241

What is the number one cause of blindness, chronic kidney disease and non-traumatic limb amputation in the US?

Diabetes

242

Where is insulin produced?

Pancreatic beta cells

243

What is the metabolic affect of insulin?

Inhibits gluconeogenesis

244

Where does insulin not influence glucose uptake?

The brain

245

What stimulates the secretion of insulin?

Plasma glucose

246

What should occur after a meal in regards to glucose and insulin?

Glucose utilization exceeds glucose production and a transition from exogenous glucose delivery to endogenous glucose production occurs

247

What are counter regulatory hormones?

Support glucose production and oppose insulins functions

248

What are examples of counter regulatory hormones?

Glucagon, epinephrine, growth hormone and cortisol

249

What causes diabetes?

Either an inadequate supply (Type I) or a inadequate tissue response (Type II) to insulin

250

Where is glucagon produced?

Pancreatic alpha cells and processed in the gut

251

Where is glucagon receptor location?

In the liver

252

What causes glucagon production to halt?

Glucose

253

What is the function of Glucagon?

Increases breakdown of hepatic glycogen stores and hepatic glucose synthesis
Stimulates fatty acid oxidation and ketogenesis
Stimulates hepatic uptake of amino acids

254

What type of response can occur when there is multiple hormonal inputs?

Additive or Synergistic

255

What is a protective mechanism to prevent rapid fluctuations in glucose production?

Push-pull mechanism on the alpha and beta cells of the pancreas

256

What are the rapid effects of insulin on the body?

Increased transport of glucose, amino acids and K into the insulin sensitive cells

257

What are the intermediate effects of insulin on the body?

Stimulation of protein synthesis
Inhibition of protein degradation
Activation of glycolytic enzymes and glycogen synthase
Inhibition of phosphorylase and gluconeogenic enzymes

258

What are the delayed effects of insulin on the body?

Increase in mRNA for lipogenic and other enzymes

259

What what glucose level does the body inhibit insulin secretion?

90mg/dL

260

At what glucose level does the body secrete glucagon, epinephrine and growth hormone

75mg/dL

261

At what blood glucose level does cortisol secretion occur and the patient experiences cognitive dysfunction?

60mg/dL

262

At what blood glucose level does lethargy occur?

45mg/dL

263

At what blood glucose level does coma and convulsions occur?

30mg/dL

264

At what blood glucose level does permanent brain damage and death occur?

15mg/dL

265

What is the incidence of type I diabetes out of all of the current diabetics?

5-10%

266

What is thought to cause type I DM?

Autoimmune pathology, unknown trigger although environmental triggers such as viruses, dietary proteins, drugs or chemicals may initiate the autoimmune process

267

When does the preclinical period of type I DM occur?

Lasts from 9-13 years and is characterized by production of antibodies to beta cell antigens with loss of beta cell function

268

When do clinical symptoms begin to manifest in type I DM?

After 80-90% of lost beta cell function

269

What are the manifestation of type I DM?

Sudden sever onset of hyperglycemia
Fatigue
Weight loss
Polyuria, polydypsia
Blurred vision
Intravascular volume depletion

270

How is diabetes diagnosed?

Fasting glucose greater than 126mg/dL
Random glucose greater than 200mg/dL
HA1C greater than 7

271

What is the incidence of type II DM out of all diabetics?

85-95%

272

What are common themes associated with type II diabetes?

Overweight, resistant to ketoacidosis, susceptible to hyperglycemia, hyperosmolar non-ketotic state

273

What lifestyle choices are associated with type II diabetes?

Poor food choices
Inactivity
Aging
Genetic influences

274

What is the pathophysiology behind type II DM?

A relative beta cell insufficiency and insulin resistance

275

What is unique regarding the diagnosis of type II DM?

Most people are not diagnosed for approximately 4-7years after the disorder appears

276

Why dont type II DM patients experience ketoacidosis?

They are making insulin but have a peripheral resistance to it

277

What are the three important defects in type II DM?

An increase rate of hepatic glucose release
Impaired basal and stimulates insulin secretion
Inefficient use of glucose by peripheral tissues

278

What causes the increase in hepatic glucose release in type I DM?

The reduction of insulin's normal inhibitory effects on the liver and abnormalities in regulation of glucagon secretion

279

What is metabolic syndrome?

A constellation of clinical biochemical characteristics frequently seen in patient who have or at risk of developing type II DM

280

What are characteristics of metabolic syndrome?

Fasting plasma glucose greater than 100mg/dL
Abdominal obesity
Serum triglyceride levels greater than 150
Low serum HDL cholesterol
Blood pressure greater than 130/85

281

What does the HA1C measure?

Long term glucose control

282

What is the normal range for HA1C?

4-6%

283

At what HA1C puts a patient at risk of microvasculature and microvascular disease?

Greater than 6.5%

284

What is the first line treatment for DM?

Dietary control and exercise, reduces adiposity and improves hepatic /peripheral tissues insulin sensitiveit, enhances post receptor insulin action and may increase insulin secretion

285

What pharmacologic treatments can be given for diabetics?

Oral antidiabetics
IV or IM insulin preparations

286

What adverse effects are associated with Sulfonylureas and meglitinides oral anti diabetics?

Delays contractile recovery after myocardial ischemia and expand ischemic zone

287

What are adverse effects of Metformin?

Lactic acidosis especially with renal insufficiency

288

How would you calculate a daily dose of insulin for your patient?

kg x 0.3 (divide by 24 if you want an hourly dose)

289

Why is it essential to have tight control over blood glucose levels?

To prevent continues progression of microvascular complications

290

What is the pathology of DKA?

A profound loss of insulin production and activity that stimulate lipolysis and fatty acid breakdown which leads to ketosis

291

What are the primary ketones produced during DKA?

Acetoacetate and beta-hydroxybutyrate

292

What clinical manifestation occur during DKA episode?

Profound hyperglycemia, polydypsia, polyuria, dehydration, decreased renal blood flow, coma and kussmaul breathing

293

Why is rehydrating the patient essential in treating DKA?

If insulin is administered in the absence of electrolyte replacement, water will move from the extracellular space back into the cells causing vascular collapse

294

What are characteristics of hyperglycemic hyperosmolar coma?

Severe hyperglycemia
Hyperosmolarity and dehydration

295

How does Hyperglycemic hyperosmolar coma occur?

Precipitated by decreased fluid intake

296

Why does HHNS cause a higher incidence of coma?

Osmolality may exceed 340mOsm/L

297

If the plasma osmolality is greater than 320 what can be given for fluid replacement?

Large volumes of hypotonic saline

298

What type of microvascular complications are associated with diabetes?

Non-occlusive microcirculatory disease and impaired auto regulation of blood flow and vascular tone

299

What is the most common neuropathy experienced by diabetics?

A distal polyneuropathy

300

What are symptoms of distal polyneuropathy?

Large sensory and motor fibers
Small fibers areas affect proprioception
Sensitivity to touch pain and temperature is impaired

301

What is the result of damage to the vasoconstrictor fibers and impaired baroreceptor function in patients with DM?

Autonomic neuropathy

302

What are CV symptoms associated with autonomic neuropathy?

Abnormalities in heart rate control (does not respond to exercise)
Systolic and diastolic dysfunction with reduced EF
Orthostatic HoTN
Silent ischemia

303

What GI effects associated with autonomic neuropathy?

Impaired gastric secretion and motility
Gastroparesis diabeticorum
Diarrhea/Constipation

304

What is the treatment for gastroparesis?

Small meals, reduced fat content and a prokinetic (reglan)

305

When should an insulin infusion be initiated for intraoperative use?

Ideally a continuous insulin infusion should be started at least two hours before surgery

306

What is an appropriate range for glucose intraoperatively?

Between 120-180mg/dL

307

At what glucose level does glycosuria and dehydration begin to occur?

Greater than 200mg/dL

308

What is the typical rule of thumb when giving one unit of insulin?

Decreases glucose by 25-30mg/dL

309

What is the typical dose for an insulin infusion pump?

0.02u/kg/hr

310

When does the onset of gestational diabetes typically occur?

During the second half of gestation and resolves at parturition

311

What is thought to cause gestational diabetes?

Increasing levels of progesterone, cortisol, prolactin and somatotrophin (counter regulatory hormones)

312

How can gestational diabetes affect the pregnancy?

Associated with an increased rate of C-sections as well as perinatal morbidity and mortality

313

Who are at risk for gestational diabetes?

Those who have family history of diabetes, especially on the maternal side
Older than 25
Baby more than 9 lbs/ birth defect
Too much amniotic fluid
Overweight before pregnancy
Unexplained stillbirth or miscarriage

314

Where are thyroidglobulins located?

In the colloid portion of the follicle

315

What is unique about the action of thyroid hormone?

Although an amine, it enters the affected cell and changes the mRNA like a steroid hormone

316

If a thyroid deficiency occur, how long might it take to see changes in thyroid levels?

2-3 months

317

How is T3 and T4 synthesized?

Iodide converted to iodine
iodine attaches to tyrosine on TGP
T3 and T4 formed and TGH is removed in lysosomes

318

What is the active form of thyroid hormone?

T3

319

What is the breakdown of thyroid hormone released?

T4 93%
T3 7%

320

How is thyroid hormone absorbed?

Via ion trapping

321

How does TSH function to increase the amount of thyroid hormone?

Increases the amount of iodide into the cell for synthesis
Enzyme synthesis via increased DNA transcription of RNA

322

What protein is T4 bound to?

Thyroid binding globulin

323

What protein is T3 bound to?

Mainly to albumin

324

When is thyroid hormone active?

The unbound form

325

What pathology is associated with an elevated TSH?

Hypothyroidism

326

What diseases are associated with hypothyroidism?

Goiter
Hashimotos

327

What pathology occurs when there is a decrease in circulating TSH?

Hyperthyroidism

328

What disease is associated with hyperthyroidism?

Graves disease

329

How does thyroid hormone exert its affects?

By binding to specific receptors in the nuclei of cells in target tissues

330

What effects does thyroid hormone have on the body?

Metabolism
Thermoregulation
Growth/Development
Myelination in childhood

331

What metabolic processes does T3 and T4 stimulate?

Oxidative metabolism
Basal metabolic rate
Heat production

332

What are the main causes of hyperthyroidism?

Graves disease
Pregnancy
Thyroiditis
Adenoma
TSH secreting pituitary adenoma

333

What treatment is given to patients with hyperthyroidism?

Propylthiouracil (PTU)
Propranolol

334

What is the goal in treating hyperthyroidism?

Euthyroid

335

What are clinical manifestation of hyperthyroidism?

Weight loss, diarrhea, warm moist skin, weakness of large muscles, osteopenia, jittery, heat intolerance, tachycardia, HTN and heart failure

336

What are the two most common differential diagnoses associated with thyroid storm?

MH and Neuroleptic malignant syndrome

337

Why should the provider use caution in patients with a history of long term use of amiodarone?

Can cause thyroid storm because it increases plasma thyroid hormone

338

What are clinical manifestation of thyroid storm?

Hyperpyrexia >40 degrees
Sweating
Tachycardia
Afib
N/V/D
Tremors, delirium, apathy

339

What are triggers for thyroid storm or crisis?

Surgery, infection or trauma

340

How should thyroid storm be managed?

Hydration
O2
Cooling
Pentothal
Inotropes
Beta blockade

341

What drugs should be avoided in thyroid storm?

Aspirin
Ketamine

342

How does Propylthiouracil treat hyperthyroidism?

It prevents the production of more T3 and T4 in the thyroid and blocks the conversion of T4 to T3 outside of the thyroid

343

How does Iodides (Lugol's solutionl treat hyperthyroidism?

Blocks release of stored thyroid hormone from thyroid gland

344

How do glucocorticoids treat hyperthyroidism?

Blocks conversion of T4 to T3

345

How are beta blockers used in the treatment of hyperthyroidism?

Reduces symptoms caused by heightened response to catecholamine, blocks conversion of T4 to T3

346

How is Lugol's solution administered?

Via NG tube

347

What is the mechanism of action of methimazole in treating hyperthyroidism?

Prevents production (synthesis) of more thyroid hormone

348

What term is used to describe fetal hypothyroidism?

Cretinism

349

What are clinical presentations of hypothyroidism?

Slow mental function
Dry skin
Arthralgias
CV depression
intolerance to cold
slow gastric emptying

350

If hypothyroidism is left untreated what is the end result?

Myxedema Coma

351

What are clinical manifestations of Myxedema Coma?

Typically seen in elderly obese females
Become increasingly withdrawn, lethargic, sleepy and confused
Slip into coma

352

What findings in a patients history may cause concern for Myxedema coma?

Previous thyroid surgery
Radioiodine
Default hormone therapy

353

What is the most common reason for hypothyroidism to occur?

Previous thyroid surgery thyroid adenoma

354

What diagnostic test is typically used in determining thyroid pathology?

TSH

355

What are some anesthetic implication for patients undergoing a thyroidectomy?

Must be euthyroid preoperatively
Thorough airway assessment
Avoid drugs that stimulate the SNS

356

What are the main airways concerns in patients with goiters?

Positional dyspnea
Dysphagia
Vena Caval obstruction if tumor extends into the chest

357

What are some intraoperative considerations for patients having a thyroidectomy?

Avoid premedication/use regional when possible
CV monitoring
Protect against hypothermia

358

Where are the parathyroid glands located?

Four glands on the posterior aspect of the thyroid gland

359

What lab value is often drawn when removal the of thyroid gland has occurred?

Ionized Calcium due to removal of the thyroid gland

360

What stimulates the release of parathyroid hormone?

Hypocalcemia

361

How does hypercalemia affect PTH?

Suppresses both hormonal synthesis and release of calcium

362

How does PTH maintain normal plasma concentration of calcium?

Promotes the movement of calcium across three interfaces
GI tract
Renal tubules
Bone

363

What is required in order for the parathyroid gland to function?

Vitamin D

364

What is the active form of vitamin D?

Calcitrol

365

What hormones promotes the storage of calcium?

Calcitonin

366

Why is calcitonin said to be counter regulatory to PTH?

It inhibits bine mobilization and lowers blood calcium

367

What is typically the cause of primary hyperparathyroidism?

Adenoma

368

What is typically the cause of secondary hyperparathyroidism?

Inadequate D3 produced, hypocalcemia stimulates hight PTH levels

369

What are clinical manifestations of hyperparathyroidism?

Dehydration, bone pain, confusion, anorexia, constipation, muscle weakness, HoTN, shortened QT

370

What is the most common cause of primary hypoparathyoidism?

Surgical parathyroid resection

371

What arecommon causes of secondary hypoparathyroidism?

Acute hypomagnesiumesmia
Reduced vitamin D
Chronic renal insuffiency
Acute systemic illness
Blood transfusion
Resistent tissues

372

What drugs have been known to cause hypoparathyroidism?

Ketoconazole
Doxorubicin

373

What are clinical presentations of hypocalcemia?

Tetany
Perioral numbness
Paresthesias
Muscle cramping Seizures
Hyper reflexia
HoTN
Bradycardia
Prolonged QT

374

What two signs are used to determine if hypocalcemia is present?

Ckvostek sign
Trousseau sign

375

What is the most common post op complication associated with removal of the parathyroid glands?

Tetany, be aware if the patient develops stridor can be cord tetany

376

What may cause refractory hypocalcemia after removal of the parathyroid glands?

Hypomagnesaemia

377

How might hypocalcemia affect neuromuscular blockade?

Hypocalcemia causes muscle weakness and sensitivity to muscle relaxants