L8 - Fluid And Electrolyte Balance Disturbance Flashcards
(74 cards)
1
Q
Body fluids are distributed in two
compartments.. what are they?
A
1.Extracellular fluids[ECF] Which includes
interstitial fluid & intravascular fluid
2.Intracellular fluids[ICF]
2
Q
Percentages of water in the body
A
60% of body weight is water
Of which 40% from intracellular fluid
20% from ISF and plasma
3
Q
What do fluids contain?
A
Water w/
- Electrolytes
- Minerals
- Cells
4
Q
Measured osmolality
A
measured by freezing point depression (by osmometer)
It’s a measure of the osmotically active particles in a fluid
In plasma:
Na, K, Cl, HCO3, urea, glucose
5
Q
Calculated osmolality
A
It’s a rough estimate of the plasma osmolality (285-295mmol/kg)
Determined by the equation:
2(Na) + urea + glucose (mM)
6
Q
Osmolar gap
A
Difference b/w calc & meas osmolality - usually < 10mM
7
Q
Fluid intake and fluid output
A
Processes that happen naturally to maintain the body’s homeostasis
8
Q
Influences that regulate the fluid intake and output
A
9
Q
What are the two cases where fluid needs to be regulated in the body
A
Hypervolemia and hypovolemia
10
Q
Hypervolemia definition
A
Excessive fluid volume
11
Q
Hypovolemia definition
A
Deficient fluid volume
12
Q
Hypervolemia regulation
A
It will inhibit 1. ADH release 2. Aldosterone release 3. Thirst =increased urination and diluted urine
13
Q
Hypovolemia regulation
A
It will stimulate: 1. Thirst 2. ADH release 3. Aldosterone release =decreased urination and concentrated urine
14
Q
ADH fxn
A
Reduces water passage into urine
15
Q
Aldosterone fxn
A
Promotes reabsorption of sodium and h2o
16
Q
Daily fluid balance
A
Input- 2.6L
Output- 2.6L
(To maintain homeostasis)
17
Q
Neutral balance
A
Input = output
18
Q
Positive balance
A
Input> output
Can lead to edema
19
Q
Negative balance
A
Input< output
Leads to dehydration
20
Q
Hypo + hyper + iso
A
Reflect electrolyte balance
21
Q
Contraction and expansion
A
Reflects the water balance
22
Q
Fluid contraction
A
Deficient fluid
23
Q
Fluid expansion
A
Excess fluid
24
Q
What causes extracellular contraction
A
Not enough water and not enough sodium
25
What causes extracellular expansion
Too much water and too much sodium
26
What can also be a cause of fluid contraction and expansion
Aside from fluid disturbances or could also be a result of a change in electrolytes
(Water like to follow sodium)
27
Fluid status indication - physical exam
Mucous membranes and turgor
28
Fluid status indication - blood
Hematocrit (HCT) -> measures plasma volume
If someone is dehydrated the majority of his plasma is going to be molecules therefore hematocrit and hemoglobins are gonna be high
29
Fluid status indication - plasma
BUN -> blood, urea, nitrogen
30
Fluid status indication - urine
— Output (volume)
— Specific gravity: <1.003 -less concentrated urine prod.
>1.030 -more concentrated urine prod.
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Fluid status indication - electrolytes
Mainly sodium and potasssium
32
Hypovolemia definition
Decrease in ECF volume ( intravascular and interstitial volume) - could be due to a loss in water and electrolytes or only water
33
What causes an isotonic volume deficit
1. Decreased intake of isotonic fluids
2. Excessive vomiting and diarrhea
3. Excessive hemorrhage
4. Excessive urine output
2,3,4 -> isotonic v. deficit bcz these are fluids that contain electrolytes so you’re losing isotonic fluid
34
Hypovolemia manifestations
— Decreased tissue perfusion (passage of fluid from circulation or lymphatics to tissue)
— Decreased blood volume (hypotension, tachycardia, oliguria)
— tissue dehydration ( loss of skin turgor, possible temperature elevation)
35
Hypovolemia lab studies in urine
```
Very concentrated urine low output
Urinalysis may be normal
Sodium conc. Low
Chloride conc. Low
Osmolality high
Oliguria
```
36
Hypovolemia lab studies in blood
- High serum sodium =dehydration
- If sodium normal then patient is not dehydrated but hypovolemia (losing isotonic solution)
- high BUN/plasma creatinine level ( if not excreted = renal problems)
- HCT and plasma albumin high
37
Hypervolemia
```
Excess of isotonic fluid in the intravascular and
interstitial spaces
-isotonic fluid retention
- secondary hyperaldosteronism
- iatrogenic hypervolemia
```
38
Isotonic fluid retention
Oliguric state eg renal failure (no urine excretion)
39
Secondary hyperaldosteronism
Inappropriate renal reabsorption of water and sodium and increased renal secretion of potassium
40
Iatrogenic hypervolemia
If doctor gives patient too much fluid
41
Hypervolemia pathology
Excess in blood volume results in high capillary pressure
42
Hypervolemia clinical manifestations
Edema
Hypertension ( high cardiac output)
Bounding pulse (throbbing felt over arteries in the body due to forceful heartbeat)
Increased urinary output
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Cation electrolytes
Na+
K+
Ca++
Mg+
44
Anion electrolytes
HCO3-
Cl-
PO4-
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ICF major electrolytes
K+
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ECF major electrolytes
Na+
47
What are the 4 headings which are discussed with disease
Intake
Compartmental shift
Output/loss
Possible artifact (normally, loses bcz of GI and kidney disturbances)
48
Hyponatremia
Too little sodium or too much water (diluted)
49
Hypernatremia
Too much sodium or too little water (concentrated)
50
How to evaluate water and Na balance problems
By comparing:
- serum sodium with urine sodium
- serum osmolality with urine osmolality
- careful clinical examination
51
When serum Na is low and urine Na< 20 mmol/l
This is due to dilution ( retaining fluid)
52
When serum Na is low and urine Na is >20 mmol/l
It is due to depletion (losing fluid)
53
Hyponatremia symptoms
Nausea/vomiting
Muscle weakness
Headache
Lethargic; possible seizure and coma is very low (<125 mmol/l)
54
Why do hyponatremia symptoms develop
Usually bcz of cells swelling and cerebral edema
55
Hyponatremia
1. Low total body sodium
2. Normal total body sodium
3. High total body sodium
56
Low total body volume=
Low ECF volume/ hypovolemic
57
Normal total body sodium=?
Normal ECF volume/ euvolemic/ normovolemic
58
High total body sodium=?
High ECF volume/ hypervolemic
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Hyponatremia with low body sodium
Na loss greater than body loss
Reduction in total body water
Dehydrated patients
60
Causes of hyponatremia with low body sodium
GIT disorders= vomiting /diarrhea /intestinal obstruction
Burns
Diuretic therapy
Adrenal insufficiency:
Infants/ elderly who can’t demand fluids
Patients who are vomiting/ comatose/ not allowed oral fluids
Profuse sweating or diarrhea- water loss more than the intake
61
Hyponatremia with normal body sodium
In SIADH (syndrome of inappropriate anti diuretic hormone)
Aka - euvolemic or dilutional hyponatremia
Water retained but no signs of fluid overload
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Hypernatremia with high sodium concentrations
| Signs and symptoms
```
Altered mental state
Lethargy
Irritability
Seizures
Fever
Increased thirst
```
63
Hypernatremia with high sodium concentrations
| Cause
```
Cellular dehydration
Usually iatrogenic (caused by docs and nurses) ex. Administering hypertonic fluid >0.9% normal saline
```
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Hypernatremia with low sodium concentrations
Lose more water than sodiums
| Thirst mechanism increase water intake
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Hypernatremia with normal body sodium causes
```
Increased insensible water loss- fever, excessive burns, mechanical ventilation
Diabetes insipidus (causes body fluid imbalance)
Drugs (lithium causes nephrogenic diabetes insipidus)
```
66
Why is potassium deadly?
It affects muscles and influence skeletal and cardiac activity (particularity the heart= arrhythmia)
67
Serum potassium
98% of body potassium is inside the cell
Normal serum concentration:
3.5->5.5 mmol/l
68
Hypokalemia signs and symptoms
```
Alkalosis
Shallow respiration
Irritability
Confusion
Weakness
Arrhythmias
Lethargy
Weak pulse
Low intestinal motility
```
69
Hypokalemia
Serum potassium below 3.5 mmol/l
Increase it but not more than 5.5
monitor it with an ECG
70
Hypokalemia causes
Diarrhea
Diuretics
Poor K intake
Steroid administration
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Hyperkalemia signs and symptoms
```
Muscle cramps-> weakness-> paralysis
Drowsiness
Low blood pressure
EKG changes
Dysrythmias
Abdominal cramps
Diarrhea
Oliguria
```
72
Hyperkalemia
Serum potassium higher than 5.5mmol/l
| More dangerous than hypo bcz cardiac arrests are more frequent with high K+
73
Hyperkalemia causes
Renal disease
Massive cellular trauma (ex chemotherapy)
Addison’s disease (hypoaldosteronism-> stop K+ secretions)
Decreased blood pH (ex acidosis in DM)
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