Hyper/Hypo BS

Question 1

What is the main extracellular cation?

Answer 1

Sodium

Question 2

The “-volemias” refer to what is being perceived on _________ ______

Answer 2

physical exam

Question 3

In order for this to happen, there must be an increase in both water AND sodium

Answer 3

Hypervolemic Hypernatremia

Question 4

What is the most common form of hypervolemia hypernatremia?

Answer 4

Iatrogenic – from the administration of sodium bicarbonate

Question 5

What is another cause of hypervolemia hypernatremia?

Answer 5

Primary aldosteronism

Question 6

What does primary aldosteronism cause hypervolemia hypernatremia?

Answer 6

Increased aldosterone causes increased sodium reabsorption

sodium reabsorption causes water to passively follow it, which is why hyperaldosteronism can cause hypervolemia

Question 7

To be hypovolemic and hypernatremic, there must be more _________ loss than _______ loss if one is losing both

Answer 7

more WATER loss, than sodium loss

Question 8

Losses of water and/or sodium can be classified as renal loses or extrarenal losses – what are examples of both?

Answer 8

renal losses: renal disease or diuretics

extrarenal losses: sweat, stool

Question 9

If the clinical history and physical exam cannot distinguish between renal and extrarenal losses, what are you going to do!?

Answer 9

Look at their urine – urine electrolytes will tell you the difference!

Question 10

If the water/sodium loss is occurring extrarenally, will sodium concentration in the urine increase or decrease? why?

Answer 10

Decrease! the kidneys are still working here! so they will hold on to that sodium making the sodium concentration less in the urine!

Question 11

What if the cause of hypovolemic hypernatremia is renal? what will the sodium urine concentration look like?

Answer 11

HIGH! kidneys suck – can’t hold on to sodium, out it goes.

Question 12

If the sodium concentration is greater than ____ meq/L the sodium losses are renal. If they are less than ______ meq/L the sodium losses are extrarenal.

Answer 12

20!

Question 13

Although patients may appear euvolemic, they are technically losing or gaining some water?

Answer 13

Losing

Question 14

What are the two causes of euvolemic hypernatremia?

Answer 14

Diabetes insipidus and hypodipsia

Question 15

Whats the difference between central diabetes insipidus and nephrogenic diabetes insipidus?

Answer 15

Central is a problem in the posterior pituitary – you aren’t making ADH

Nephrogenic is when there is no response to ADH

Question 16

What are two cases when the body inappropriately increases the intravascular volume resulting in hypervolemia, hyponatremia?

Answer 16

Heart failure and cirrhosis

Question 17

Heart failure and cirrhosis cause hyper or hypovolemia? and hyper or hyponatremia?

Answer 17

Hypervolemia, hyponatremia

Question 18

To be hypovolemic and hyponatremic, there must be both water and sodium loss, but relatively more ______ loss than ______ loss.

Answer 18

sodium, water

Question 19

If we can’t tell on physical exam if someone is hypovolemic and hyponatremic, what are we going to do?

Answer 19

Look at the urine

If the urine sodium concentration is greater than 20meq/L, the kidneys must be losing the sodium.

If the urine sodium is less than 20meq/L, the the sodium must be lost in some other way such as sweat, stool, or edema

Question 20

Adrenal insufficiency, hypoparathyroidism, primary polydipsia, and SIADH can all cause?

Answer 20

Euvolemic hyponatremia

Question 21

If patients with euvolemic hyponatremia have kidneys that are functioning normally, they will be urinating large or small amounts?

Answer 21

Large! trying to maintain clinical euvolemia

Question 22

Osmolality refers to the amount of _____ dissolved per kilogram ______

Answer 22

solute, solvent

Question 23

An increase in glucose, lipids, proteins, or urea will raise or lower serum osmolality? why?

Answer 23

Raise! because they will pull water into the intravascular space to re-equilibrate things.

This would lead to an increased water to sodium ratio and thus hyponatremia.

Question 24

In uncontrolled diabetes mellitus, the glucose concentration can raise/lower the serum glucose levels?

Answer 24

Raise the serum glucose levels!

Water can be drawn into the intravascular space in an attempt to maintain fluid balance. This can result in hyponatremia and even hyperosmolar coma.

Question 25

The hypervolemic states are secondary to?

Answer 25

Fluid overload

1. Can be an IV solution-generated hypernatremic one

OR

2. An internally-generated HYPOnatremic one (CFH, cirrhosis)

Question 26

In hypernatremia there is either net ______ of salt or net ______ of water.

Answer 26

Gain, loss

Question 27

In hyponatremia, there is either net _____ of salt or net ______ of water.

Answer 27

Loss, gain

Question 28

What is the main intracellular cation?

Answer 28

Potassium

Question 29

Serum potassium concentration can increase secondary to what three basic mechanisms?

Answer 29

1. Increased intake
2. Decreased urinary excretion
3. Increased movement of potassium from cells into the bloodstream

Question 30

Is it easy to eat too much potassium result in increased serum potassium?

Answer 30

No – thats a lot of potassium.

Question 31

Are you more likely to get hyperkalemia from eating too much or from getting an infusion of potassium at an inappropriately high dose?

Answer 31

Definitely the infusion

Question 32

Decreased urinary excretion is a mechanism for increased serum potassium – what are the three ways that this can happen?

Answer 32

1. Renal failure
2. Decrease in flow rate
3. Hypoaldosteronism

Question 33

How would renal failure lead to hyperkalemia?

Answer 33

The kidneys have difficulty filtering and excreting potassium

Question 34

Why would a decreased flow rate in the nephron cause hyperkalemia?

Answer 34

A decreased flow rate in the distal nephron can perceive high concentration of potassium, which can inhibit further secretion of potassium in the nephron.

Question 35

Why would hypoaldosteronism lead to hyperkalemia?

Answer 35

Aldosterone is the hormone responsible for potassium excretion – low levels will result in low excretion

Question 36

If there is too much acid in the blood (aka too much hydrogen), how will this affect potassium concentrations?

Answer 36

Hydrogen will move from the blood into the cell, and potassium will move out (as they have equal charges) – resulting in hyperkalemia

Question 37

What if blood is alkalotic? what will happen to potassium serum levels then?

Answer 37

If there is not enough hydrogen in the blood, cells will release hydrogen into blood in exchange for potassium, which will cause HYPOkalemia.

Question 38

Insulin will cause potassium to enter or exit the cell?

Answer 38

Enter!

Question 39

If someone has insulin deficiency, what effect will this have on serum potassium levels?

Answer 39

Serum potassium levels will be high! If the insulin is deficient, potassium isn’t going to move into the cell.

Question 40

Hypokalemia can be caused by what three mechanisms?

Answer 40

1. Decreased intake
2. Increased loss (renal or GI)
3. Movement of potassium from the blood into cells

Question 41

Is hypokalemia from decrease intake common?

Answer 41

No – very rare. More of a contributing factor

Question 42

What effect will an increased distal flow rate in the nephron have on potassium levels?

Answer 42

Increased distal flow rate will wash away potassium, making the lumen of the nephron appear to be lacking in potassium, which in turn causes potassium secretion.

Aka, hypokalemia.

Question 43

Vomiting and diarrhea will cause hyper or hypokalemia?

Answer 43

Hypokalemia

Question 44

Hyperkalemia – what will you see on EKG?

Answer 44

Peaked t-waves

Question 45

Aldosterone causes reabsorption of ______ and secretion of _______

Answer 45

sodium, potassium