Fluid & Electrolyte Disturbances

Front 1

What does extracellular fluid consist of?

Back 1

Intravascular fluid
Interstitial fluid

Front 2

What is the most abundant extracellular ion?

Back 2

Na+

Front 3

What is the most abundant intracellular ion?

Back 3

K+

Front 4

What is the key to osmotic pressure?

Back 4

Na+

Front 5

What is the key to hydrostatic pressure?

Back 5

plasma proteins (albumin)

Front 6

What fluids and/or electrolytes are related to the RAA/Aldosterone system?

Back 6

fluid, Na+ & K+

Front 7

What fluids and/or electrolytes are related to the Atrial Natriuretic Peptide system?

Back 7

fluid
Na+

Front 8

What fluids and/or electrolytes are related to fluid shifts?

Back 8

fluid
Na+

Front 9

What fluids and/or electrolytes are related to Thirst?

Back 9

Fluid, Na+

Front 10

What fluids and/or electrolytes are related to kidney function?

Back 10

fluid
Na+
K+

Front 11

What is hypervolemia?

Back 11

too much fluid in the intravascular space

Front 12

What causes hypervolemia?

Back 12

1. decreased kidney function
2. too much IV solution (increased osmolarity)

Front 13

What are the signs and symptoms of hypervolemia?

Back 13

1. increased BP - BP = HR x Vol X PVR
2. increased JVD
3. bounding pulse --> increased vol = increased CO --> arteries are "full"
4. Weight Gain

Front 14

What is the compensation for hypervolemia?

Back 14

fluid shift - IV --> IS (THIRD SPACING)

Front 15

What fluids and/or electrolytes are related to the ADH (antidiuretic hormone) system?

Back 15

Fluid

Front 16

What is "third spacing"?

Back 16

it is when the fluid is pushed from the intravascular space to the interstitial space. this will cause edema

Front 17

How is hypervolemia corrected?

Back 17

increased renal output **it's the only correction!

Front 18

What is hypovolemia?

Back 18

not enough fluid in intravascular space

Front 19

What causes hypovolemia?

Back 19

- not enough fluid intake
- increased clearance of fluids because of impaired tubules

Front 20

What are the signs and symptoms of hypovolemia?

Back 20

- decreased BP
- INCREASED HR (HPA)
- Weight loss
- weak pulse

Front 21

How does the body compensate for hypovolemia?

Back 21

- fluid shift (from IC or IS --> IV)

Front 22

How does the body correct hypovolemia?

Back 22

- increasing thirst
- decreasing urine output by ADH & RAA

Front 23

What signs and symptoms occur after compensation fluid shift?

Back 23

intracellular dehydration:
- dry skin
- poor skin turgor
- dry mucous membrane
- confusion (brain cells dehydrated)

Front 24

Explain the MOA for thirst.

Back 24

hyperosmolarity (hypovolemia) --> triggers osmoreceptors --> stimulates "thirst center" (hypothalamus) --> increased thirst --> increased fluid intake

Front 25

What triggers thirst?

Back 25

- increased osmolarity
- decreased blood volume (hypovolemia)
- dryness of muscous membranes of mouth

Front 26

What is the MOA for ADH (anti-diuretic hormone)?

Back 26

hyperosmolarity (hypovolemia)
--> stimulates osmoreceptors --> stimulates "thirst center" (hypothalamus) --> posterior pituitary --> ADH --> adds pores to renal tubules which increases permeability to water --> water is reabsorbed and results in decreased urine output

Front 27

What is the MOA for RAA (renin-angiotensin-aldosterone) and how does it help correct hypovolemia?

Back 27

- acts to reabsorb Na+
- renin is produced in the juxtaglomerular cells in the kidney and it stimulates formation of angiotensin I (inactive form) --> ACE (angiotensin converting enzyme) converts this to its activate form which is angiotensin II --> stimulates the secretion of aldosterone which increases Na+ reabsorption. H2O is passively reabsorbed by osmotic pressure. ***Angiotensin II also causes vasoconstriction in blood vessels which leads to increased BP & angiotensin II can lead to vascular remodelling

Front 28

What is hyponatremia?

Back 28

low sodium levels

Front 29

What causes hyponatremia? (list 3)

Back 29

- decreased Na+ intake (rare)
- increased Na+ loss (burns, N/V, diuretics)
- dilution of Na+ (sweating --> stimulates thirst; kidney dysfuntion - impaired excretion of H2O; replaced fluid losses with D5W)

Front 30

What does N/V result in?

Back 30

loss of Na+
loss of fluid
loss of acid

Front 31

What are the signs and symptoms of hyponatremia?

Back 31

- edema - swelling (fluid in interstitial space)
- vascular hypovolemia - osmotic pressure will move fluid to interstitial space
- decreased BP
- increased HR (HPA)

- behavioural/neurological changes - lethargy, confusion, seizures AND less Na+ to DEPOLARIZE cells

Front 32

How does the body compensate for hyponatremia?

Back 32

fluid shift (from IV - IS)

Front 33

How does the body correct hyponatremia?

Back 33

RAA/Aldosterone
decreased [Na+] & decreased blood volume stimulate the release of renin which is a hormone produced by juxtaglomerular cells in the kidney --> it converts angiotensin to angiotensin I (inactive form) --> ACE (angiotensin converting enzyme) converts angiotensin I to angiotensin II (active form) --> the effects are release of aldosterone from the adrenal cortex --> causes Na+ reabsorption followed by H2O reabsorption. Angiotensin II also causes vasoconstriction which increases BP. And lastly, it causes vascular remodelling

Front 34

What is aldosterone?

Back 34

- a mineral corticoid
- secreted from adrenal cortex
- secreted when Na+ levels are low or K+ levels are high
- increases reabsorption of Na+
- increases excretion of K+ from distal tubule of kidney
- increases passive H2O reabsorption

Front 35

What is hypernatremia?

Back 35

too much sodium

Front 36

What causes hypernatremia?

Back 36

- food intake (rare)
- inappropriate administration of saline solution (D5 NS)
- over-secretion of ALDOSTERONE (Cushing's)
- Renal failure
- altered Na+ loss in relation to H2O loss (Diabetes insipidus, ADH, DM, polyuria, profuse sweating, diarrhea)

Front 37

How does the body compensate for hypernatremia?

Back 37

fluid shift from IC & IS --> IV

Front 38

What are the signs and symptoms of hypernatremia?

Back 38

- intracellular dehydration
- dry skin
- poor skin turgor
- dry mucous membranes
- thirst
- restlessness
- hypervolemia
- wt. gain, increased BP, increased HR, bounding pulse

Front 39

How does the body correct hypernatremia?

Back 39

ANP (Atrial Natriuretic Peptide)
- increased blood volume causes the heart to stretch which causes the atrium cells within the heart to release ANP --> this increases GFR decreases Na+ reabsorption and increases Na+ excretion. it also inhibits the release of RAA

Front 40

Why is K+ important?

Back 40

it is needed for CELLULAR function
* sudden increases can be fatal but body can adapt to small increases

Front 41

What is hypokalemia?

Back 41

low K+ levels

Front 42

What causes hypokalemia?

Back 42

- decreased intake
- elderly, alcoholism, anorexia nervosa
- loss of K+
- renal disorders
- GI disorders (diarrhea)
- vomiting/NG suctioning
- diuretic use - inhibits reabsorption of Na+ and increases secretion of K+

Front 43

What are the signs and symptoms of hypokalemia?

Back 43

- mild losses - no symptoms
- severe losses - neuromuscular excitability decreased (skeletal muscle weakness, smooth muscle atony (lacking tone), and cardiac dysrhythmias
- cardiac dysrhythmias are also due to changes in membrane excitability (EKG changes)

Front 44

What is hyperkalemia?

Back 44

too much K+

Front 45

What causes hyperkalemia?

Back 45

- increased intake (rare)
- shift of K+ from cells to ECF
- cell trauma (burns)
- insulin deficiency (insulin promotes entry of K+)
- hypoxia
- decreased renal secretion
- K+ sparing diuretics

Front 46

What are the signs and symptoms of hyperkalemia?

Back 46

- muscles: early - hyperactivity
late - weakness and flaccid paralysis
- cardiac - decreased cardiac conduction (cardiac arrest) and more rapid depolarization
- kidney - oliguria (abnormally small urine output)

Front 47

What does the body do in response to hyperkalemia? (this mechanism is not sufficient for correction).

Back 47

high K+ causes release of aldosterone from the adrenal cortex --> aldosterone speeds up ATPase to get 2 K+ out for each Na+ reabsorbed

Front 48

How can you manage fluid shifts?

Back 48

1. observe signs & symptoms
2. check serum electrolyte levels
3. measure intake and output (considering insensible loss of approx. 600 mL/day) *should not balance exactly

Front 49

What are some hypotonic solutions?

Back 49

ex. 0.45% NS or 0.33% NS (not usually given to people with low BP cause it will further drop)

Front 50

What are some isotonic solutions you could give for maintenance?

Back 50

NS, R/L

Front 51

What are some hypertonic solutions?

Back 51

D5W R/L, D5W 0.45% NS

Front 52

What is the main cause for the release of ADH?

Back 52

low blood volume or hyperosmolarity
- result: in increased water reabsorption

Front 53

What is the main cause for the release of RAA?

Back 53

low sodium levels (hyponatremia) or low blood volume
- result: Na+ reabsorption (primary)
H2O reabsorption (secondary)

Front 54

What is the main cause for the release of aldosterone?

Back 54

- low Na+, high K+ or low blood volume
- release is stimulated by angiotensin II from the RAA system
- result: Na+ reabsorption (increases)
H2O reabsorption (secondary)

Front 55

What is the main cause for the release of ANP (atrial natriuretic peptide)?

Back 55

- triggers by stretching of the heart because of increased blood volume and hypernatremia
- result: increases GFR which in turn decreases Na+ reabsorption (Na+ is excreted)