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1

Adrenal Medulla

1. Controlled by?

2. When stimulated it secretes?

2 Adrenal Cortex

1. Three zones: What are they?

2. What do they secrete?

Adrenal Medulla

1. Controlled by nervous system

2. When stimulated secretes epinephrine and norepinephrine into adrenal veins

Adrenal Cortex

1. Glomerulosa: mineralocorticoids… aldosterone

2. Fasciculata: glucocorticoids… cortisol

3. Reticularis: sex hormones

2

Adrenocorticotropic Hormone ACTH

What does it do?

Primarily what?

Remember, -tropin or -tropic means to stimulate.

Therefore, adrenocorticotropic means “to stimulate the adrenal cortex”

Function: Stimulates synthesis and secretion of adrenocortical hormones (cortisol, androgens, and aldosterone)

ACTH primarily stimulates cortisol

3

Describe the normal ACTH physiology

 

4

What does cortisol stimulate? 4

1) Gluconeogenesis

2) Protein mobilization

3) Fat mobilization

4) Stabilizes lysosomes

 

5

Adrenal Insufficiency vs Crisis

1. Adrenal Insufficiency is what?

2. What kind of disease is this?

3. Adrenal Crisis is what?

4. What kind of condition is this?

Adrenal Insufficiency

1. Failure of adrenal glands to produce essential BASAL secretion of steroids

2. Insidious wasting disease

Adrenal Crisis

3. Failure to RESPOND to the increased demands caused by stress or SUDDEN INABILITY to secrete essential steroids

4. Life-threatening condition

6

Nova’s likely diagnosis:

Adrenal insufficiency, of which there are two forms:?

1. Primary adrenal insufficiency (Addison’s disease)

 

2. Secondary adrenal insufficiency

 

7

Adrenal insufficiency?

1. Primary adrenal insufficiency (Addison’s disease) results from?

2. Secondary adrenal insufficiency results from?

Primary adrenal insufficiency (Addison’s disease)

1. Results from destruction or dysfunction of the adrenal cortex

Secondary adrenal insufficiency

2. Results from inadequate stimulation of adrenal cortex by ACTH (***By far the most common cause is chronic administration of exogenous steroids!)

8

Describe how the adrenal pathway changes in primary adrenal insufficiency?

9

What would happen to the adrenal pathway with exogenous administration of corticosteriods?

10

Decreased blood pressure?

Decreased cortisol:

1. Cortisol up-regulates alpha1-adrenergic receptors on vascular smooth muscle (what does stimulation of the alpha1 receptors do again?) so a decreased amount would…? 3

Decreased aldosterone:

2. Aldosterone increases Na reabsorption by renal cells, leading to increases in extracellular fluid volume and blood volume, venous return, cardiac output, and arterial pressure.  Therefore a decrease in aldosterone would…? 2

1.

-Cause vasodilation and

-decrease in peripheral vascular resistance

-and decreased BP

2.

-More NA+ to be excreted in the urine and also more water excretion.  

-decreased blood pressure

11

Adrenal Insuffieciency

Pulse rate increase?

Compensatory mechanisms as a result of:  4

1. Decreased volume

2. With decreased volume we have decreased arterial pressure

3. ➔ baroreceptor reflex

4. ➔ increased sympathetic outflow and therefore an increase in heart rate

12

Decreased blood glucose?

Decreased cortisol:

One action of cortisol is to increase blood glucose concentration by promoting gluconeogenesis and decreasing glucose uptake by the tissues and therefore a decrease in cortisol would…?

Decrease blood glucose levels

13

Hyperkalemia?

Decreased aldosterone:

In addition to stimulating Na reabsorption, aldosterone stimulates K secretion by the renal principal cells and therefore a decrease in aldosterone would…?

inhibit K secretion

14

Late Distal Tubule/Collecting Duct Area

1. The principal cells reabsorb what? 2 And secrete what?

2. Aldosterone exerts its effects by increasing the function of the what?

 

15

Hyponatremia?

Decreased aldosterone

Aldosterone increases Na reabsorption by renal principal cells.  Therefore, with decreased aldosterone we would have…?

Increased Na and water excretion

16

In contrast to indolent and progressive course of chronic adrenal insufficiency, ***adrenal crisis presents as a life-threatening emergency in which the primary manifestation is what??

hypotension

17

1. When you have a patient that presents with what always consider an adrenal crisis if there is not an immediately apparent  cause?

 

2. ***The hypotension in adrenal crisis typically is

resistant to what? 2

 

3. If the missing _______ is not replaced, death will ensue!

 

1. severe hypotension

2. catecholamine and IV fluid administration!

3. cortisol

18

Adrenal Crisis 

Where is it seen? 4

1. In a previously undiagnosed patient with primary adrenal insufficiency who has been subjected to serious infection or other acute, major stress.

2. In a patient with known primary adrenal insufficiency who does not take more glucocorticoid during an acute infection (can occur during acute viral infections such as influenza) or other major illness, or has persistent vomiting caused by viral gastroenteritis or other gastrointestinal disorders.

3. After bilateral adrenal infarction or bilateral adrenal hemorrhage.

4. Rarely in patients with secondary adrenal insufficiency, can be seen in patients withdrawn abruptly from suppressive doses of corticosteroids

19

Adrenal Crisis

1. Presentation? 2

2. Dx? 4

3. Tx? 2

1. Presentation

-Marked hypotension

-Abdominal and flank pain

2. Diagnosis

-Clinically oriented for abrupt withdrawal from exogenous steroids

-For primary adrenal insufficiency, a short cosyntropin test

(Cosyntropin [ACTH analogue] injected,

-plasma cortisol levels measured in 60 minutes,

-primary adrenal insufficiency excluded if poststimulation level > 550 nmol/L)

3. Treatment

-If adrenal crisis suspected or diagnosed, IV glucocorticoids

-D5NS may be required to correct hypovolemia and hypoglycemia

20

Pheochromocytoma

1. What is it?

2. The tumor releases what?

3. which causes? 5

4. reversible?

5. Where is the tumor located the majority of the time?

1. A tumor derived from neural crest cells of the sympathetic nervous system that is responsible for about 0.1-2% of all cases of hypertension.

2.  The tumor releases catecholamines

3. Which cause episodic (this way most of the time) or sustained signs and symptoms, such as

-palpitations,

-sweating,

-headaches,

-fainting spells, and

-hypertensive emergencies.

4. A surgically correctable form of HTN!

5. Majority of the time tumor located in adrenal medulla

21

Catecholamines have two major effects, each mediated by a Beta1 receptor. What are they?

1. Increased heart rate

2. Increased contractility (or force of contraction)

22

Symptoms can be described by the effects that epinephrine and norepinephrine have on the various organ systems:

Catecholamines have two major effects, each mediated by a Beta1 receptor: How does this affect the blood vessels? 2

1. Vasoconstriction of cutaneous blood vessels via Alpha1 receptor

2. Vasodilation of skeletal muscle blood vessels via Beta2 receptor

23

Describe the 90% rule in pheochromocytoma

4

90% tumor (or 10% tumor):

1. 90% of the time they arise from the adrenal medulla (with the other 10% they can arise anywhere but the majority occur in the mediastinum or abdomen)

2. 90% of the time adrenal pheochromocytoma will be unilateral (otherwise it is bilateral and is likely a genetic syndrome)

3. 90% of the time it is not malignant

4. 90% of the time it occurs in adults

24

Keys with pheochromocytoma:

1. History is exceptionally important! Symptoms? 4

2. Diagnosis is made by? 2

3. Once diagnosis is made: Hunt for the source how?

1. Pt usually has episodes of

-hypertension,

-headache,

-palpitation, and

-sweating

2. Demonstrating

-elevated urinary excretion of catecholamines or their metabolites (metanephrines and vanillylmandelic acid)

-DURING a period of hypertension

3.  CT of abdomen with focus on adrenal glands

25

You order a 24 hour urine measurement of what?

The test is positive, a finding that provides nearly conclusive evidence of a pheochromocytoma

A CT scan confirms a 3cm mass on Helen’s right adrenal gland… she needs an adrenalectomy

vanillylmandelic acid (VMA)

26

Surgeons dislike performing surgery on someone with unstable blood pressure… and there is a natural inclination for the body to have a sympathetic response when surgery is performed leaving a patient with a pheochromocytoma to have a high morbidity and mortality unless blood pressure is controlled prior to surgery

1. Current recommendation is to initiate what before surgery?

2. Why do we do this?

3. Then start what 3-4 days after?

4. WHy?

1. initiate alpha blockade first to

2.

-reduce afterload and

-total peripheral resistance…

3. then to start a beta blocker about 3-4 days thereafter

4. to reduce the effects of the increased amount of catecholamines in the bloodstream

27

1. Primary hypothyroidism usually has what kind of onset?

2. Typical labs include? 2

3. Emergency?

1. Primary hypothyroidism usually has insidious onset

2. Typical laboratory findings include

-low T4 and

-high TSH

3. Usually no urgency when suspecting primary hypothyroidism

28

Describe the hypothyroidism feedback system

29

Myxedema Coma

1. Occurs in individuals with waht?

2. How serious is this?

3. Correct diagnosis requires what?

4. Initiation of treatment is what?

5. Affected patients commonly in what population?

1. long-standing preexisting hypothyroidism presents with life-threatening decompensation

2. **Rare, potentially life-threatening

3. high degree of suspicion

4. empirical decision

5. geriatric

30

Myxedema Coma

Presentation

Severe decline in metabolic function? 8

1. Alteration in mental status

2. Hypothermia

3. Bradycardia

4. Hypotension

5. Hypoventilation (increased CO2 retention)

6. Cardiovascular collapse

7. Decreased drug clearance

8. Usually patient has history of primary hypothyroidism or previous thyroid surgery