Week 4 - ELectrolytes Flashcards
1
Q
What are some of the functions of electrolytes?
A
- water balance
- cellular growth and metabolism
- maintaining acid-base balance
- blood clotting
- cellular depolarization and repolarization
2
Q
Range for Na+
A
135 - 145
3
Q
What can happen in the body when there are changes in sodium?
A
Neurological issues (including seizures)
4
Q
Why can Neurological issues (including seizures) happen when there are changes in sodium in the body?
A
Altered tonicity causing swelling of brain cells (hyponatremia) and shrinking of brain cells (hypernatremia)
5
Q
Potassium normal range
A
3.5 - 5.0
6
Q
What are changes in Na+ concentrations indicative of?
A
Generally - the body’s underlying fluid status rather than changes in the amount of Na+
7
Q
Why is potassium important?
A
cell repolarization, especially cardiac repolarization
8
Q
How do we recognize hyperkalemia?
A
tall peaked t-waves eventually progressing into cardiac arrest due to the inability to properly repolarize
FATAL
9
Q
What happens with hypokalemia?
A
Heart becomes more irritable and prone to dysrhythmias (remember: lethal injections are a sedative + concentrated potassium).
This will initially manifest as Premature Ventricular Contractions. You may also see muscle cramps.
10
Q
Magnesium normal range
A
1.7 - 2.2
11
Q
Why is magnesium important?
A
It is usefl in inhibiting labor.
necessary to promote potassium absorption in the kidneys
12
Q
What do elevated potassium levels do?
A
Stabilize cell membranes, making depolarization less likely
13
Q
How do elevated magnesium levels present?
A
decreased or absent deep tendon reflexes
14
Q
How do low levels of magnesium present?
A
hyperactive reflexes and muscle spasms
15
Q
Ca++ normal range
A
8.5 - 10.5
16
Q
What important functions does Ca++ support?
A
cardiac conduction
blood clotting
bone health
17
Q
How does hypocalcemia present?
A
muscle irritability, specifically Trousseau’s and Chvostek’s sign
18
Q
What are complications with hypocalcemia?
A
Increases risk of osteoporosis
Risk of bleeding due to impaired blood clotting
19
Q
What are complications with hypercalcemia?
A
initially causes increaesd HR and BP
Prolonged hypercalcemia will cause cardiac arrest and increased risk of kdiney stones
risk of blood clots
20
Q
Phosphate normal range
A
3.5 - 5.0
21
Q
What is phosphate’s relationship with Ca+=?
A
Phosphate exists in the inverse proportion to Ca++
Hypophosphatemia will present like hypercalcemia
22
Q
Why is phosphate important?
A
for ATP production, which is particularly affects the respiratory muscle function
23
Q
What can CKD cause?
A
hyperkalemia, hypermagnesemia, hyperphosphatemia (and therefore hypocalcemia)
24
Q
What do we do if potassium levels are high?
A
administer insulin to put the potassium IN cells
25
What does hyponatremia do?
brain cells expand b/c they are hypertonic --> cerebral edema
26
What does hypernatremia do?
brain cells shrink b/c the water in the cells will go towards the higher concentration of solutes (cells are hypotonic so water leaves them)
27
signs of hyper or hyponatremia?
altered mental status
```
Confusion
Headache
Lethargy (hyponatremia) / irritability (hypernatremia)
Coma
Seizures
```
Body more likely to handle chronic rather than acute hypo/hypernatremia
28
Treatment of hypernatremia
Replacement of fluid with hypotonic fluid (half NS)
NS (.9%) has 154 mEq, so it will cause hypernatremia
29
Causes of hypernatremia
1. relative hypernatremia (more common)
- dehydration
- diabetes insipidus
2. absolute hypernatremia: excessive sodium intake or disorders of sodium reabsorption
30
Signs and symptoms of hypernatremia
S&S of dehydration
Thirst, since osmoreceptors drive the thirst response
31
Causes of hyponatremia
1. Intake of free water
- overhydration with hypotonic IVF
- psychogenic polydispisa
2. fluid overload
- CHF, renal failure
- SIADH
3. loss of salt due to diuretic use
32
Signs and symptoms of hypernatremia
```
Neuro symptoms (swelling of brain cells)
S/sx of fluid overload (bounding pulses, elevated BP, etc.)
```
33
What is a risk of treatment of hyponatremia?
Overlay rapid correction of hyponatremia will cause central pontine demyelination (can cause paralysis, dysphagia, AMS that is often permanent)
Should only correct by 10 mEq/24h
Overly rapid correction fo hypernatremia can cause a rebound cerebral edema
34
Who regulates potassium?
kidneys
35
What are causes of hyperkalemia?
CKD
Dietary: Intake of salt substitutes
Acidosis
Cell Lysis
- crush injury
- old RBCs
Pharm: antagonizing aldosterone (aldosterone increases Na+ retention and decreases K+ retention)
- Aldactone (direct aldosterone antagonist)
- ACE Inhibitors
36
S/sx of hyperkalemia?
TALL PEAKED T WAVES
```
Cardiac arrest (late sign)
Paresthesias (benign and nonspecific sign)
```
37
Why do we use calcium gluconate as a treatment for hyperkalemia?
to stabilize cardiac cell membranes
38
Why do we administer IV insulin to treat hyperkalemia?
to drive potassium into the cells
39
What are some other treatments for hyperkalemia?
administer furosemide - we’re using a drug’s “side effect” as a therapeutic effect in this case!
- Of course, now the fluid loss becomes a side effect that we must monitor!!
Administer potassium binders (kayexalate) – but this takes time and causes diarrhea
Albuterol
Correct any underlying acidosis
Dialysis
40
What leads to psudohyperkalemia?
Lysis of cells due to the trauma of the blood draw can cause a falsely elevated potassium
If you see a drastically elevated potassium in a patient who is asymptomatic and has no reason to be hyperkalemic, recheck
The lab will usually indicate “hemolysis” or “gross hemolysis” if they see lots of lysed RBCs
41
Nursing interventions for a pt with hyperkalemia?
Recorgnize s/sx (assess)
- EKG monitoring
- Frequent BMPs - q6h, q8h, q12h
Recognize implications/side effects of treatment
42
RN teaches a student nurse regarding the management of increased potassium levels in a client. Which action performed by the student nurse indicates effecive learning?
A. Administering sodium polystyrene sulfonate
B. Instructing a client to increase potassium and sodium intake
C. Monitoring glucose levels hourly
D. providing potassium sparing diuretics
A.
Hyperkalemia levels indicate hyperkalemia and are observed in clients with adrenal insufficiency. Administering potassium binding and excreting resin, such as sodium polystyrene sylforate, can reduce the potassium levels.
Potassium restriction should be initiated immediately to reduce the potassium levels.
Providing potassium-sparing diuretics may further lead to increase in potassium levels, and these diuretics should be avoided
43
What lab tests indicate renal impairment?
Inreased serum creatinine concentration, BUN, and potassium ion concentration levels
Normal serum creatinine cont: .5 - 1.5 mg/dL)
A serum creatinine valure of 2.0 mg/dL indicates renal impairment.
Normal concentration fo potassium ions in serum 3.5 -5.0. A K+ ion conc of 5.9 indicates kidney dysfunction
Normal value of BUN lies between 7 and 20. A BUN value of 32 indicates renal impairment.
Normal range of albumin conc between 3.5 - 5.5
44
What is oliguria a sign of?
Withholding IV potassium
Potassium chloride should not be given unless renal flow is adequate; otherwise, potassium chloride will accumulate in the body, causing hyperkalemia.
45
What are paresthesis and tetany signs of?
Hypocalcemia
46
What are muscle weakness and cardiac dysrhythmias a sign of?
potassium depletion in the skeletal and cardiac muscles:
the sodium-potassium pump facilitates conduction fo nerve impulses and muscle activity.
47
What can numbness around the mouth be a sign of?
Hypocalcemia
48
why do we use NS for hypovolemia?
B/c we don't want to add more Na+ to a hypertonic environment
49
How does ADH influence sodium concentration?
By changing the amount of water in the body
50
What is Aldosterone's role in sodium management?
Aldosterone is responsible for managing sodium levels (and decreasing potassium levels)
too much can cause you to lose K+ and retain Na+
51
How are relative and absolute hyp*natremia different?
Relative hyp*natremia - the amount of water in body has changed. Na+ level is the same, but concentration has changed.
vs.
Absolute hyp*natremia - water levels are the same, but the Na+ level has changed.
52
How do we treat relative hyp*natremia?
hydration or treatment of underlying cause of hyp*natremia
53
How do we treat absolute hyp*natremia?
We add or subtract salt from the diet/IV fluids or eliminate any drugs that cause salt loss.
54
How do we treat absolute hyp*natremia?
We add or subtract salt from the diet/IV fluids or eliminate any drugs that cause salt loss.
55
What are some causes of hypernatremia?
1. dehydration (relative hypernatremia)
2. diabetes insipidus (the body does not produce enough ADH --> overproduction of very dilute urine)
3. Hyperaldosteronism - in cases of heart failure, baroreceptors detect low CO and assume prob is dehydration --> activation of RAAS and body holds on to salt.
56
S/sx of hypernatremia
1. neurological changes (due to shrinking brain cells), especially restless, confusion, irritability + increased muscle spasticity and DTRs
2. Seizures - big risk
3. if loss of fluid has caused relative hypernatremia, then you would expect to see signs of fluid loss (thirst, dry mouth, skin tenting, hypotension)
57
Treatment of hypernatremia
Fluid replacement (ideally with IV fluids that are hypotonic - you don't want to add more salt to the problem)
Treat underlying condition causing dehydration
58
Causes of hyponatremia
Intake of free water
- overhydration with hypotonic IVF
- psychogenic polydipsia
Fluid overload
- CHF renal failure
- SIADH (syndrome of inappropriate antidiuretic hormone)
salt losses (hard to lose salt form the body w/out losing fluid as well; but some conditions like burns or certain meds/diuretics can cause this)
Inadequate salt intake
59
S/sx of Hyponatremia
Neurologic symptoms (typically headaches and confusion) this time due to neuronal swelling) again, seizures are a big risk)
60
Treatment of hyponatremia
Asymptomatic: fluid restrictions, salt tabs, diuresis
symptomatic: hypertonic IV fluids solutions (3% saline)
often, b/c hyponatremia due to hemodilation, don't want to give fluids b/c --> fluid overload
61
Causes of hyperkalemia
Kidney disease (acute or chronic)
cellular destruction (lysis of cells)
- pseudohyperkalemia (lysis or RBCs during collection of blood
- old blood transfusion
Acidosis (cells trade K+ ions for H+, leading to lots of K+ in the blood, even though total body K+ hasn't changed)
Dietary
Pseudohyperkalemia
62
S/sx of hyperkalemia
tall peaked t waves
63
treatment for hyperkalemia
place pt on cardiac monitor
calcium gluconate to stabilize cardiac cell membranes and prevent cardiac sequelae
kayexalate
insulin with "push" K= into the cells (but you must give dextrose with it or your pt's blood sugar will drop)
B2 agonists like albuterol will also push K+ into cells
dialysis
64
Causes of hypokalemia
Removal of GI contents
- Vomiting
- NG suction
Diuretic therapy - especially loop diuretics like furosemide
hyperaldosteronism
inadequate magnesium (magnesium is required for kidney to uptake potassium)
65
S/sx of hypokalemia
muscle cramps and spasms
irritable heart muscle - premature ventricular contractions and other dysrhythmias
66
Treatment of hypokalemia
Replacement - consider replacing magnesium too
- IV vs. PO replacement
- PO risks: GI upset
- IV risk:
- - Cardiac arrhythmias (lethal injection). Never give quicker than 20 mEq/hr
- - phlebitis/burning - slow down rate, use central line
aldosterone-antagonist medications (aka 'potassium sparing diuretics' like spironolactone) - retain K+
Dietary supplementation
67
Why is calcium important?
plays an important role in cardiac conduction, bone health, and clotting
in the sarcoplasmic reticulum in cardiac myocytes
68
What regulates calcium levels?
Parathyroid Gland
Thyroid Gland
Vitamin D levels
Phosphate levels
69
Causes of hypercalcemia
Parathyroid disorders (too much PTH)
Corticosteroids
Excessive oral intake
70
S/sx of hypercalcemia
Even though calcium can generally be understood as a “cell membrane stabilizing” electrolyte, the influence of Ca++ on heart tissue means you will initially see tachycardia and hypertension due to calcium’s role in the sarcoplasmic reticulum
Prolonged hypercalcemia eventually “wears out” the heart --> bradycardia
Increased BP
Bounding pulses
Hypercoagulability
Kidney Stones
71
Treatment of hypercalcemia
Ca++ binders
Monitor EKG
Loop diuretics
72
Causes of hypocalcemia
Parathyroid disorders
Low calcium intake
High phosphate levels
Low Vitamin D
73
S/sx of hypocalcemia
Trousseau’s and Chvostek’s Signs
Muscle spasms
Hypotension and non-specific EKG changes
74
Treatment for hypocalcemia
Monitor for osteoporosis: DEXA scan; fall precautions if (+) osteoporosis
Give calcium
Give vitamin D
75
Why is phosphorous important?
Needed for muscle function --> diaphragm
76
Hyperphosphatemia
See hypocalcemia since this is where the problems tend to arise
77
Hypophosphatemia
respiratory issues/muscle weakness
78
what are patients on furosemide at risk for and why?
hypokalemia b/c furosemide is a loop diuretic and causes loss of K+
79
What is Na+ responsible for?
1. Maintaining fluid balance in the body
| 2. Maintaining electrical charge (as the primary cation in the ECF)
80
What is Na+ regulated by?
Aldosterone (RAAS) (controls Na+)
ADH (controls amt of water in body)
81
What type of hypernatremia is more common?
relative - dehydration
82
beer potomania
gallons of beer a day
beer is hypotonic --> hyponatremia
not as at risk for seizures, but definitely still at risk
hypomagnesia
anemia (not adequate folic acid and B12)
fall risk
83
How does central pontine demyelination happen and what are the risks?
Over treatment of hyponatremia
The risks or dysphagia, paralysis, and AMS - often permanent
84
How do we avoid central pontine demyelination?
Don't increase pt's fluids quicker than 10mEq/24h
85
What can giving fluids too quickly do to someone with hypernatremia?
Can cause cerebral edema
You should not give fluids to a hypernatremic pt faster that 12mEq/24h
86
Why will you have hyperkalemia when you are acidotic?
Acidosis causes hyperkalemia
H+ and K+
cells will take on H+ to compensate for acidosis --> excess H+ in cell --> have to trade out K+ to maintain electric neutrality
relative hyperkalemia
87
hyponatremia
swelling of the brain cells
88
hypernatremia
shrinking of the brain cells
