Endocrine - Exam 4 Flashcards
1
Q
A normal glucose level requires a balance between what 3 things?
A
Glucose usgae
Endogenous production
Dietary intake
2
Q
What is the primary source of glucose production via glycogenolysis & gluconeogenesis?
A
The liver
75% of the glucose released by the liver is freely metabolized by tissues in the brain, GI tract, and red blood cells
3
Q
What hormones help regulate blood glucose level?
A
Glucagon
Epi
Growth hormone
Cortisol
4
Q
Glucagon plays a primary role by what 3 ways?
A
Stimulating glycogenolysis
Simulating gluconeogenesis
Inhibiting glycolysis
5
Q
What is the most common endocrine disease?
Affects ___ in ___ adults
A
Diabetes
1 in 10 adults
6
Q
Diabetes results from:
A
an inadequate supply of insulin and/or tissue resistance to insulin
glucose levels rise, leading to microvascular and macrovascular damage
7
Q
What is the difference in Type 1A and 1B diabetes?
A
Type 1a DM is caused by an autoimmune destruction of pancreatic β cells, leading to minimal or absentinsulin production
Type 1b DM is a rare, non-immune disease of absolute insulin deficiency
8
Q
Type 2 DM is also ______ and results from defects in ____ receptors and _____ pathways
A
Non-immune
Insulin
Signaling
9
Q
T1DM accounts for ___% of DM cases and is usually diagnosed before age ___
A
5-10%
40
10
Q
A long period (9-13 yrs) of _____ antigen production occurs before onset of symptoms
At least 80-90% ____ function is lost before sustained hyperglycemia
A
B-cell antigen
B-cell
11
Q
Hyperglycemia over several days/weeks is associated with:
A
fatigue, weight loss, polyuria, polydipsia, blurry vision, hypovolemia, ketoacidosis
12
Q
T2DM accounts for >___% DM cases and is increasingly seen in what pt population?
Normally present for how many years before diagnosed?
A
> 90%
Increasingly seen in younger pts & children over the past decade
4-7 years
13
Q
Explain the 3 abnormalities seen in DM2
A
- Impaired insulin secretion
- ↑hepatic glucose release *c/b a reduction in insulin’s inhibitory effect on liver
- Insufficient glucose uptake in peripheral tissues
In initial stages, tissues become desensitized to insulin, leading to ↑secretion
Over time, pancreatic function decreases & insulin levels become inadequate
14
Q
DM2 is characterized by insulin resistance in what 3 places?
A
Skeletal muscle
Adipose
Liver
15
Q
Causes of insulin resistance include:
Diagnostics for T2DM?
A
Abnormal insulin molecules
Circulating insulin antagonists
Insulin receptor defects
Fasting BG
HbA1c
16
Q
Criteria for diabetes charts
A
17
Q
T2DM treatment
A
Diet
Exercise/weight loss
- improves hepatic & peripheral insulin sensitivity
PO anti diabetics
- Metformin
- Sulfonylureas
Insulin
18
Q
What is metformin?
A
A biguanide, preferred initial drug tx
- Enhances glucose transport into tissues
- ↓TGL & LDL levels
19
Q
What are sulfonylureas?
A
Stimulates insulin secretion, enhances glucose transport into tissues
- d/t diabetic progressive loss of B cell function, Sulfonylureas not effective long term
- SE’s include hypoglycemia, weight gain & cardiac effects
20
Q
Treatment for DM chart
A
21
Q
When is insulin necessary?
A
All DM1 cases and 30% of DM2
22
Q
Explain different types of insulin
A
Rapid acting (Lispro, Aspart) provide glucose-control @ mealtimes
Short acting (regular)
Basal/Intermediate acting (NPH, Lente)
Long acting (Ultralente, Glargine)
23
Q
What is important to note with long acting insulin?
A
- hypoglycemia is most dangerous complication
- exacerbated by ETOH, metformin, sulfonylureas, ACE-I’s, MAOI’s, Non-selective BB’s
24
Q
What is hypoglycemia unawareness?
Treatment?
A
Pt becomes desensitized to hypoglycemia and doesn’t show autonomic sx
- Neuroglycopenia ensues→fatigue, confusion, h/a, seizures, coma
- Tx: PO or IV glucose (may give SQ or IM if unconscious)
25
Insulin pictures
26
What is DKA?
Complication of decompensated DM, mortality 1-2%
- High glucose exceeds the threshold for renal reabsorption
- Creating osmotic diuresis & hypovolemia
27
DKA is more common in ____ and often triggered by what??
*Diagnostic picture for DKA also attached*
DM1
Infection/illness
28
DKA treatment
- IVF
- Regular insulin
- Correct acidosis: bicarb
- Electrolyte replacement
29
Correction of glucose without simultaneous correction of sodium may result in:
Cerebral edema
30
Regular insulin dose for DKA
Loading dose 0.1u/kg + low dose infusion @ 0.1u/kg/hr
31
What is HHS?
Hyperglycemic hyperosmolar syndrome
- Characterized by severe hyperglycemia, hyperosmolarity & dehydration
- Evolves over days to weeks
- When blod glucose exceeds renal glucose absorption, massive glucosuria occurs
32
HHS normally occurs in who?
Symptoms?
DM2 >60 y/o
polyuria, polydipsia, hypovolemia, HoTN, tachycardia, some acidosis
33
Tx of HHS
fluid resuscitation, insulin bolus + infusion, e-lytes
34
What are DM complications?
- Microvaascular
- Nephropathy
- Peripheral neuropathy
- Retinopathy
- Autonomic neuropathy
35
What does microvascular complications of DM mean?
nonocclusive microcirculatory dz w/impaired blood flow
36
Symptoms of DM neuropathy
What about if the pt also has ESRD?
HTN, proteinuria, peripheral edema,↓GFR (hyperkalemic acidosis)
HD, PD, transplant
37
What is peripheral neuropathy?
- distal symmetric diffuse sensorimotor neuropathy
- Starts in toes/feet, progresses proximally
- Loss of large sensory & motor fibers, reducing light touch & proprioception
- Loss of small nerve fibers decreases pain/temp perception
- Neuropathic pain develops
- Ulcers develop from unnoticed mechanical & traumatic injury
- Recurrent infections & amputation wounds
38
What is retinopathy?
Visual impairment ranges from color loss to blindness
- caused by microvascular damage
39
Autonomic neuropathy symptoms
Cardiovascular sx: abnormal cardiovascular dynamics, loss of HR variability, ortho-HoTN & dysrhythmias
GI: ↓gastric secretions & motility, eventually gastroparesis
General: N/V, early satiety, bloating, epigastric pain
40
Treatment of autonomic neuropathy
glucose control, small meals, prokinetics
41
During DM preop, what complication is possible with autonomic neuropathy?
Silent ischemia
42
What does autonomic neuropathy predispose pts to?
peri-op dysrhythmia and HoTN
43
What is insulinoma?
Rare, benign insulin-secreting pancreatic tumor
- Occurs 2x more in women than men, normally in 50s-60s
44
Diagnosis for insulinoma is based on what?
Whipple triad
- Hypoglycemia w/fasting
- Blood glucose <50 w/sx
- Sx relief w/glucose
45
What do you do in preop for insulinoma?
Other tx?
Give diazoxde (inhibits insulin release from B cells)
verapamil, phenytoin, propranolol, glucorticoids, octreotide, surgery
46
What can occur intra-op and post op following removal of insulinoma?
Hypoglycemia can occur intra-op, followed by hyperglycemia once tumor removed
47
Thyroid gland is composed of what?
Where is it attached?
two lobes joined by an isthmus
attached to the anterior & lateral trachea, with upper border just below the cricoid cartilage
48
What does the thyroid gland contain?
a capillary network, which is innervated by the adrenergic and cholinergic nervous systems
49
Production of thyroid hormone comes from availability of _____.
Explain how this works
Exogenous iodine
Iodine is reduced to iodide in the GI tract, rapidly absorbed, then transported into thyroid follicular cells
- Iodide binds to thyroglobulin and yields inactive monoiodotyrosine and diiodotyrosine
- ̴25% monoiodotyrosine & diiodotyrosine undergo coupling w/thyroid peroxidase to form thyroxine (T4) and triiodothyronine (T3)
- The T4/T3 ratio is 10:1
50
Thyroid function is regulated what 3 things?
Hypothalamus, pituitary, thyroid glands
51
The hypothalamus secretes _________, which signals the anterior pituitary to release of ________
Thyrotropin-releasing hormone (TRH)
thyrotropin-stimulating hormone (TSH)
52
TSH binds to thyroid receptors and enhances the synthesis/release of _____
T3 & T4
## Footnote
TSH is also influenced by plasma levels of T3 & T4 via a negative feedback loop
53
_______ is best test of thyroid action at the cellular level
TSH assay
54
What is a normal TSH level?
0.4-5.0 milliunits/L
55
_____ is used to test pituitary function and TSH-secretion
TRH stimulation test
56
What is hyperthyroidism?
Symptoms?
Hyperfunctioning thyroid gland w/ excessive hormone secretion
sweating, heat intolerance & fatigue w/insomnia, CV compromise (T3); osteoporosis and weight loss may occur
57
The majority of hyperthyroidism cases are caused by what:
Graves disease
toxic goiter
toxic adenoma
58
Hyperthyroidism s/s chart
59
What is Graves disease?
Autoimmune, c/b thyroid-stimulating antibodies, stimulating growth, vascularity, and hypersecretion
- The thyroid becomes enlarged and may develop goiter
- Leading cause of hyperthyroidism, effects 0.4% population
60
Diagnostic labs for Graves
+TSH antibodies, low TSH, high T3 & T4
61
Extreme thyroid enlargement may cause what?
dysphagia, difficulty swallowing, and inspiratory stridor from tracheal compression
62
Treatment of Graves
1st line is antithyroid drug, methimazole or propylthiouracil (PTU)
- iodine therapy
- beta blockers
- surgery
63
Why is iodine therapy used in Graves?
iodine thrapy can inhibit release of thyroid hormones, but effect is temporary, therefore reserved for preop correction or thyroid storm
64
Why do you use beta blockers in Graves?
β-blockers don’t affect the underlying abnormality, but may relieve sx
- Propranolol impairs the peripheral conversion of T4 to T3
65
When is surgery for graves disease recommended? What surgery is it?
Subtotal thyroidectomy
When medical tx has failed
66
Surgical complications of subtotal thyroidectomy
hypothyroidism, hemorrhage, hematoma, tracheal compression, RLN damage, and parathyroid damage
67
In emergent cases in pts with Graves, what is usually given?
IV BBs, glucocorticoids, and PTU usually necessary
68
Graves symptoms picture
69
What is thyroid storm?
Triggered by?
Life-threatening hyperthyroid exacerbation
Triggered by stress, trauma, infection, medical illness, or surgery
70
Why does postop thyroid storm most often occur?
Inadequately treated hyperthyroid pts after emergency surgery
71
Treatment of thyroid storm?
Mortality rate?
antithyroid drugs and supportive care
20%
72
What is hypothyroidism?
Primary hypothyroidism results in ↓T3 & T4 despite adequate TSH
## Footnote
Hypothyroidism or myxedema effect 0.5-0.8% adults
73
What are the 1st and 2nd most common causes of hypothyroidism?
1st most common cause is ablation of the gland by radioactive iodine or surgery
2nd most common type cause is idiopathic and probably autoimmune
74
What is Hashimoto thyroiditis?
an autoimmune hypothyroidism, often involving a goiter and usually affects middle-aged women
75
Symptoms of hypothyroidism
cold intolerance, weight gain, nonpitting edema
May also experience SIADH, fluid overload, pleural effusions & dyspnea; GI function is slow so possible ileus
76
Hypothyroidism s/s chart
77
DOC for hypothyroidism?
Levothyroxine
78
Preop implications for hypothyroidism
Assess airway compromise d/t goiter
Slower gastric emptying, aspiration rx
If elective case, Thyroid tx should be initiated at least 10 days prior
If emergent surgery: IV Thyroid replacement along with steroids ASAP
79
What is myxedema coma?
Rare, severe form of hypothyroidism characterized by delirium, hypoventilation, hypothermia, bradycardia, HoTN, and dilutional hyponatremia
- Hypothermia is the cardinal feature d/t impaired thermoregulation
- Occurs most commonly in elderly women w/ long hx of hypothyroidism
**This is a medical emergency!!!*
80
What is myxedema coma triggered by?
infection, trauma, cold, and CNS depressants
81
Treatment of myxedema coma
IV L-thyroxine or L-triiodothyronine
IV hydration w/glucose solutions, temp regulation, e-lyte correction, and supportive care, vent if required
82
What is a goiter?
Swelling of thyroid gland d/t hypertrophy & hyperplasia of follicular epithelium
- In most cases, a goiter is assoc w/a compensated euthyroid state
83
Causes and treatment of goiter
Causes: lack of iodine, ingestion of goitrogen, or a hormonal defect
Most cases are treated with L-thyroxine
84
When is surgery indicated with a goiter?
Surgery indicated only if medical tx is ineffective, and goiter compromises AW or is cosmetically unacceptable
85
What type of testing can be used to asses how bad a goiter is?
CT scan
Flow volume loops
- Limitations in the inspiratory limb of the loop indicate extra-thoracic obstruction
- Delayed flow in the expiratory limb indicates an intra-thoracic obstruction
Echo
- cardiac compression
86
Complications of thyroid surgery
RLN injury may be unilateral or bilateral and temporary or permanent
- If unilateral, vocal hoarseness occurs without obstruction, and usually resolves in 3-6 months
- Bilateral involvement may cause AW obstruction and warrant tracheostomy
Hypoparathyroidism
Hematoma
87
Each adrenal gland consists of a ____ and a ______-
Cortex
Mdulla
88
The adrenal cortex synthesizes what?
glucocorticoids, mineralocorticoids (aldosterone), and androgens
89
What does the hypothalamus do in terms of adrenal glands?
Hypothalamus sends corticotropin-releasing hormone (CRH) to the anterior pituitary, which stimulates release of corticotropin (ACTH)
- ACTH stimulates the adrenal cortex to produce cortisol
- Cortisol helps convert NE to EPI, and induces hyperglycemia
90
What is a pheochromocytoma?
Catecholamine-secreting tumor that originates from chromaffin cells
- Excess catecholamines can lead to malignant HTN, CVA, & MI
91
The estimated locations of pheochromocytoma?
80% occur in the adrenal medulla
18% in organ of Zuckerkandle (glands
2% neck/thorax
92
Malignant Pheo’s spread through ____ & ____ systems
Venous
Lymph
93
Most Pheo’s secrete NE:EPI ratio ____, the inverse of normal adrenal secretion
85:15
## Footnote
Some secrete higher levels of EPI and, more rarely, dopamine
94
Symptoms of pheochromocytoma
h/a, pallor, sweating, palpitations, HTN, orthostatic HoTN
Coronary vasoconstriction, cardiomyopathy, CHF & EKG changes may occur
95
Diagnosis of pheochromocytoma
Dx: 24h urine collection for metanephrines and catecholamines
- CT & MRI
96
Preop considerations for pheochromocytoma
α blocker to lower BP, decrease intravascular volume
- Phenoxybenzamine: noncompetitive α1 antagonist with some α2-blocking properties
Prazosin & Doxazosin- pure α1 blockers, shorter acting w/ less tachycardia
97
What is Cushings?
What are the two forms?
Hypercortisolism
ACTH-dependent Cushings: high plasma ACTH stimulates adrenal cortex to produce excess cortisol
ACTH-independent Cushings: excessive cortisol production by abnormal adrenocortical tissue that is not regulated by CRH and ACTH
- CRH and ACTH levels are actually suppressed
- adrenocortical tumors are the most common cause of ACTH-independent Cushings
98
What is the treatment of choice for Cushing's?
Alternative treatment?
transsphenoidal microadenomectomy if resectable
- Alternatively, subtotal resection of the anterior pituitary
- Pituitary irradiation and adrenalectomy maybe necessary in some pts
- Surgical adrenalectomy is the treatment for adrenal adenoma or carcinoma
99
What is Conn syndrome?
Primary hyperaldosteronism: Excess secretion of aldosterone c/b tumor (aldosteronoma)
Secondary hyperaldosteronism: c/b elevated renin levels
- Women > men
- Occasionally assoc w/pheochromocytoma, hyperparathyroidism, or acromegaly
100
Symptoms of Conn syndrome
nonspecific, some are asymptomatic
- HTN, hypokalemia, hypokalemic metabolic alkalosis
Hallmark sx: Spontaneous HTN w/hypokalemia
101
For Conn Syndrome
In primary hyper-aldosteronism, renin activity is ______
In secondary hyper-aldosteronism, renin activity is ______
Suppressed
Elevated
102
Long term ingestion of ______ can cause a syndrome that mimics hyperaldosteronism (HTN, hypokalemia, suppression of RAAS)
Licorice
103
Treatment for Conn syndrome
Aldosterone antagonist (Spironolactone), K+ replacement, antihypertensives, diuretics, tumor removal, possible adrenalectomy
104
What is the hallmark symptom of hypoaldosteronism?
Other symptoms?
Hyperkalemia in the absence of renal insufficiency
Hyperchloremic metabolic acidosis, heart block, orthostatic HoTN, hyponatremia
105
Hypoaldosteronism may be caused by:
What is the one reversible cause?
congenital deficiency of aldosterone, low renin or ACE inhibitors
Indomethacin-induced prostaglandin deficiency is a reversible cause
106
Treatment of Hypoaldosteronism
increased sodium intake and daily fludrocortisone
107
What is the difference in the 2 types of adrenal insufficiency?
Primary AI (Addison dz): Autoimmune adrenal gland suppression
>90% of the glands must be involved before signs appear
Secondary AI: hypothalamic-pituitary suppression leading to a lack of CRH or ACTH production
108
Most adrenal insufficiency cases are _____ with causes including:
These pts lack _____
Iatrogenic
synthetic glucocorticoids, pituitary surgery, or radiation
Hyperpigmentation
109
Diagnosis of adrenal insufficiency
baseline cortisol < 20 μg/dL and remains <20 μg/dL after ACTH stimulation
## Footnote
A positive test demonstrates a poor response to ACTH
- Absolute AI is characterized by a low baseline cortisol level and a positive ACTH stimulation test
- Relative AI is indicated when the baseline cortisol level is higher, but the ACTH stimulation test is positive
110
What is the treatment of adrenal insufficiency?
Steroids
111
There are ___ parathyroid glands located behind the upper & lower poles of the thyroid
4
112
What does the parathyroid do?
Produce PTH, b/o a negative feedback that depends on plasma calcium level
113
____ stimulates the release of PTH, whereas _______ suppresses PTH synthesis and release
Hypocalcemia
Hypercalcemia
114
What does PTH do?
PTH maintains normal plasma calcium levels by promoting the movement of calcium across GI tract, renal tubules, and bone
115
In hyperparathyroidism, secretion of ____ is increased
Hyperparathyroidism is classified as what 3 types?
PTH
primary, secondary, or ectopic
116
Primary hyperparathyroidism is caused by:
benign parathyroid adenoma (90%)
carcinoma (<5%)
parathyroid hyperplasia
117
Symptoms of hyperparathyroidism
lethargy, weakness, n/v, polyuria, renal stones, PUD, cardiac disturbances
118
Diagnosis and treatment of hyperparathyroidism
Dx: Plasma calcium, 24 hr urinary calcium
Tx: surgical removal of abnormal portions of the gland
119
What is secondary hyperparathyroidism?
Treatment?
compensatory response of the parathyroid glands to counteract a separate disease process involving hypocalcemia s/a CRF
Tx: controlling the underlying dz, normalizing phosphate levels w/a phosphate binder
120
What is hypoparathyroidism?
Deficient PTH is almost always iatrogenic, d/t inadvertent removal of parathyroid glands, as may occur during thyroidectomy
121
What is pseduohypoparathyroidism?
a disorder where PTH is adequate, but the kidneys are unable to respond to it
122
Labs and symptoms of hypoparathyroidism
Dx labs: ↓PTH, ↓Ca++,↑phos
Sx: d/o speed of onset (acute hypocalcemia vs chronic hypocalcemia)
123
Acute hypocalcemia s/a after accidental parathyroid removal may cause _____ or ______
inspiratory stridor or laryngospasm
124
Chronic hypocalcemia is associated with:
fatigue, cramps, prolonged QT-I, cataracts, SQ calcifications, neurologic deficits
125
Treatment of hypoparathyroidism
Calcium replacement, Vitamin D
126
The pituitary gland consists of what 2 things?
Anterior pituitary & posterior pituitary
127
What 6 hormones does the anterior pituitary secrete under the control of the _____?
Hypothalamus
GH, ACTH, TSH, FSH, LH, prolactin
128
Posterior pituitary stores ______ and ____ after being synthesized in the _____
Vasopressin and oxytocin
Hypothalamus
129
What is acromegaly?
Dx labs?
Excessive growth hormone, most often seen with anterior pituitary adenomas
insulin-like growth factor 1 (IGF-1) is elevated
130
In acromegaly, Overgrowth of soft tissues make pts susceptible to what?
What else may occur?
Upper airway obstruction
Hoarseness & abnormal mvmt of vocal cords or RLN paralysis may occur d/t overgrowth of surrounding cartilage
131
Treatment of acromegaly
Tx: Removal of pituitary adenoma (usually transsphenoidal approach)
- If surgery not feasible, LA somatostatin analogues are the medical tx
132
Anesthesia implications for acromegaly
- Distorted facial anatomy may interfere with mask placement
- Enlarged tongue & epiglottis predisposes to upper AW obstruction and interferes w/visualization of vocal cords on DL
- Increased distance btw the lips and vocal cords d/t mandible overgrowth
- Glottic opening may be narrowed d/t vocal cord enlargement
- May require smaller ETT, VL, awake fiberoptic intubation
133
What is diabetes insipidus?
What are the 2 main causes?
Vasopressin (ADH) deficiency
Central/Neurogenic DI: destruction/dysfunction of the posterior pituitary
Nephrogenic DI: or failure of kidneys to respond to ADH
134
How are neurogenic and nephrogenic DI differentiated?
Based on response to DDAVP, which causes urine-concentration in neurogenic, but not nephrogenic, DI
135
Symptoms of DI
polydipsia and excessive, dilute UOP despite increased serum osmolarity
136
Initial tx of DI
Neurogenic/nephrogenic further treatment?
Initial tx: IV e-lytes to offset polyuria
Neurogenic DI tx: DDAVP
Nephrogenic DI tx: low-salt, low-protein diet, thiazide diuretics, and NSAIDs
137
What can cause SIADH?
Diagnosis?
intracranial tumors, hypothyroidism, porphyria, or lung cancer
Dx: hyponatremia and ↓serum osmolarity and ↑urine sodium and osmolarity
138
In SIADH, an abrupt drop in serum Na+ can result in what?
Cerebral edema and seizures
139
Treatment of SIADH
Tx: fluid restriction, Na+ tabs, loop diuretics, ADH antagonists (Demeclocycline)
- Severe hyponatremia may be treated w/hypertonic saline
140
Who does Graves disease typically occur in?
Females (7:1); 20-40 y/o
