Fluid and Electrolytes 2 Flashcards

1
Q

What are a major cause of electrolyte abnormalities?

A

Diuretics

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2
Q

What are two conditions that no abnormality exists so there is no need to treat?

A

Pseudohyperkalemia from RBC lyses

Hypocalcemia from hypoalbumenia

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3
Q

What is used for K+ replacement?

A

No bolus of IV doses
Infusion rate should not exceed 10-20 Eq/hr
Usually have limitations on concentration for peripheral infusion (max 60 mEq/L)

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4
Q

When should IV calcium be used?

A

If cardiac sx exist for hyperkalemia or hypermagnesemia

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5
Q

When do low serum concentrations of K+, Mg2+, and PO4+?

A

Low serum concentrations can occur with refeeding syndrome, add higher than standard doses to PN and glucose containing IV solution if patient at risk

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6
Q

When do high serum concentrations of K+, Mg2+, and PO4+?

A

High serum concentrations can occur in renal failure, use reduced doses in PN and IV fluids

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7
Q

What occurs when calcium and phosphorous are mixed PN?

A
  • Increased risk for calcium-phosphorous precipitation if PN mixed with
  • Sodium bicarbonate when treating hyperkalemia
  • Infusions of calcium or phosphorous when treating deficiencies
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8
Q

What are the laboratory electrolyte tests?

A

Chem 7
Chem 10
Electrolyte panel
Need to order ionized calcium seperate

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9
Q

What drugs lead to hyperkalemia?

A

K+ sparing diuretics
ACE-I, NSAIDS
Beta-antagonists
Not drug related but be aware of the possibility of pseudohyperkalemia (lysis of RBC during collection)

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10
Q

What drugs lead to hypokalemia?

A

Diuretics (except K+ sparing)
Insulin, refeeding syndrome, treatment of DKA
Beta-agonist, glucocorticoids
Amphotericin B, aminoglycosides

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11
Q

What drugs lead to hypermagnesia?

A

Lithium

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12
Q

What drugs lead to hypomagnesemia?

A
Diuretics
Amphotericin B, aminoglycosides
Cyclosporin, alcohol
Digoxin
Laxative abuse
Refeeding syndrome
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13
Q

What drugs lead to hypercalcemia?

A
Thiazide diuretics (but not loop or K+ sparing)
Lithium, Vitamin A and D toxicity, calcium
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14
Q

What drugs lead to hypocalcemia?

A

Loop diuretics
Oral Phosphorus
Phenytoin, barbituates
Vitamin D deficiency

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15
Q

What drugs lead to hyperphosphatemia?

A

Phosphate- containing enemas

IV phosphorous to treat hypercalcemia

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16
Q

What drugs lead to hypophosphatemia?

A

Diuretics
Insulin, dextrose, refeeding syndrome, treatment of DKA
Sucralfate, antacids, calcium salts

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17
Q

What type of symptoms and treatment is associated with electrolyte abnormalities with a slow and chronic onset?

A

Electrolyte abnormalities with a slow and chronic onset usually have less severe symptoms and can be gradually corrected

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18
Q

What type of symptoms and treatment is associated with electrolyte abnormalities with an acute onset?

A

Electrolyte abnormalities with an acute onset may have more severe symptoms and should be treated more aggressively

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19
Q

What are the treatment goals of electrolyte abnormalities?

A
  • Treat or prevent severe life-threatening signs and symptoms
  • Improve or correct serum electrolyte concentration to within normal values
  • Do not overcorrect
  • Avoid undesirable effects of treatment
  • Correct cause for abnormality
  • Factors to consider: Presence and severity of symptoms, Acuteness of onset
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20
Q

What is the most abundant cation in the ICF?

A

Potassium

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21
Q

Is the serum K+ a good measure of total body potassium?

A

Intracellular; serum K+ not good measure of total body potassium
Clinical manifestations correlate well with serum potassium

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22
Q

What are the cardiac abnormalities associated with hyperkalemia?

A

Ventricular fibrillation
Asystole
ECG: peaked T waves

**Life threatening

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23
Q

What are the muscle abnormalities associated with hyperkalemia?

A

Weakness

Paralysis

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24
Q

What is hyperkalemia defined as?

A

Defined as serum K+ >5mEq/L

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25
What are the causes of hyperkalemia?
Increased potassium intake (be aware of potassium sparing diuretics) Decreased potassium excretion Potassium release from intracellular space
26
What are the treatment goals of hyperkalemia?
Antagonize adverse cardiac effects (only needs to be done if having cardiac effects, needs to be done first) Reverse other sx Return serum concentrations to normal
27
What are the treatment approaches for hyperkalemia?
Antagonism of K+ if cardiac abnormalities exist (only if cardiac effects are present) Promote intracellular redistribution Remove K+ from the body
28
If cardiac effects are present (peaked T-waves, widened QRS) what are the treatment options?
IV calcium gluconate
29
IV calcium gluconate
- Only restores normal conduction of heart - Does not reduce or redistribute serum K+ - Onset 1-2 minutes; duration 10-30 minutes - May need to repeat dose if symptoms return - Calcium gluconate 10% (1 ampule) over 5-10 minutes, repeat every 30-60 minutes until ECG normalizes
30
What is the first line therapy of hyperkalemia treament for the correction of intracellular redistribution as long as acidosis is not present?
Regular insulin 5-10 units IV or SubQ Onset 30 minutes; duration 2-6 hours ``` If not hyperglycemic, give dextrose D10W, 1L over 1-2 hours D50W, 50ml over minutes Insulin promotes cellular uptake of K+ Glucose enhances exogenous insulin release and prevents hypoglycemia ```
31
What is the second line therapy for hyperkalemia treatment for the correction of intracellular redistribution?
Albuterol (B2-agonist) is second line therapy Use if patient unresponsive to insulin/glucose after 30-60 minutes 10-20mg (high dose) nebulized over 10 minutes Onset 30 min; duration 1-2 hours
32
What is the treatment used for hyperkalemia due to acidosis for correction of intracellular redistribution?
Sodium Bicarbonate Use only when hyperkalemia due to acidosis 50-100 mEq IV over 2-5 minutes Onset 30 min; duration 2-6 hours Do not infuse through same IV line as parenteral nutrition or other calcium & phosphorous solution
33
What are the treatment options for removal of K+ from the body in a patient with hyperkalemia?
Furosemide (Lasix) if normal renal function 20-40 mg IV Sodium polystyrene sulfonate (Kayexalate) 15-60 grams orally or rectally Oral route more effective and better tolerated Onset 1 hour or more; duration variable Exchanges Na+ for K+ This could potentially lead into another problem. Depends on sodium levels of the patient. Hemodialysis
34
What are the cardiac abnormalities associated with hypokalemia?
``` EKG changes- flattened T waves, presence of U wave Bradycardia PVCs Heart Block Atrial flutter/ventricular fibrillation ```
35
What are the muscle abnormalities associated with hypokalemia?
Myalgia Muscle weakness Cramps Paralysis
36
What are the causes of hypokalemia?
GI losses (V/D, NG suction) Inadequate K+ intake Alkalosis Meds
37
What are the meds that can cause hypokalemia?
Cellular redistribution- these are options for treating hyperkalemia so remember they can then cause hypokalemia. B2-agonists Insulin Renal wasting Loop and thiazide diuretics (not sparing but dumping it out) High dose antibiotics ie PCN Depletion of magnesium diminishes intracellular K+ -> K+ wasting AmphoB, foscarnet
38
When should you treat hypokalemia?
- Any low serum K+ if patient symptomatic - Underlying cardiac conditions that predisposes them to arrhythmias (cardiac therapies arent used unless there are cardiac sx) - Receiving digoxin therapy - Consider for patients receiving diuretics - Laxative abuse - Any patient with serum K+ < 3.0 mEq/L
39
What are the dietary sources that can be used for non-pharmacologic therapy?
Fresh fruits Vegetables Meats
40
A condition that causes a loss of potassium might also cause a loss of?
Chloride | Caused by: Diuretic therapy, vomiting, diarrhea
41
What are the non-pharmacologic therapy options for hypokalemia?
- some salt substitutes - Dietary sources- fresh fruits, vegetables, and meats - Dietary potassium is usually in form of potassium phosphate versus potassium chloride - Most conditions cause loss of potassium and chloride so both need replacing
42
What is involved with pharmacologic therapy for hypokalemia?
- Pharmacological replacement therapies should accompany dietary potassium - Administration orally in divided doses over several days until replete - Fatalities have occurred from IV potassium replacement - Caution with dosing in patients with renal insufficiency
43
Oral potassium
- Oral potassium is available as chloride, phosphate, and bicarbonate salts - -KCl most commonly used - -KPO4 used if depleted in both K+ and PO4- - -KHCO3 if patient acidotic (otherwise not usually used) - Available as elixir, effervescent tablet, microencapsulated particles, wax-matrix extended release - -Microencapsulated particles preferred because better taste and GI tolerability
44
What are the oral doses involved with hypokalemia treatment?
- Prevent hypokalemia with 20 mEq/day (Good prophylaxis dose. Used if starting a patient on something like digoxin.) - Treat mild hypokalemia with 40-100 mEq total dose - Treat severe deficiency with 120 mEq total dose
45
When should IV treament be used for treatment of hypokalemia?
If oral route not feasible or life-threatening symptoms
46
What are the guidelines for IV therapy for hypokalemia?
Usually 10 – 20 mEq diluted with 100ml NS Usually safe for peripheral administration Administered over 1 hour, no bolus!!!!!! Institution specific guidelines usually stipulate administration issues for example Infusion rate not to exceed 10 to 20 mEq/hr Max concentration for peripheral administration 60 mEq/L
47
What should IV therapy for hypokalemia be diluted with?
Dilute dose with saline containing solution, avoid dextrose containing solutions Dextrose promotes insulin release Insulin shifts potassium intracellularly
48
What should be monitored if infusing a patient for hypokalemia?
ECG monitoring if rate > 10 mEq/hr | Measure serum concentration after each 30 to 40 mEq increment for adults
49
What is the second most abundant ICF cation?
Magnesium NOT part of the standard chem panel...needs to be ordered separate.
50
What is hypermagnesemia defined as?
>2.4mg/dL
51
What are the neuromuscular sx associated with hypermagnesemia?
Neuromuscular blockade Muscle weakness Respiratory muscle paralysis- this would be in an extreme situation but can be fatal
52
What are the cardiovascular sx associated with hypermagnesemia?
Calcium channel blockade Hypotension Sinus bradycardia asystole
53
What are the causes of hypermagnesemia?
Renal failure in conjunction with magnesium-containing meds (cathartics, antacids, magnesium supplements) and lithium therapy
54
What is the treatment for hypermagnesemia?
-DC all magnesium supplements or mag-containing meds -Elemental calcium 100 to 200 mg IV Antagonizes neuromuscular and cardiovascular effects of magnesium Rapid onset, transient duration of action Requires repeated doses -Add loop diuretics (furosemide) and saline if normal renal function Wont help if the person has kidney failure -Hemodialysis if renal disease -May require mechanical ventilation, vasopressors, and cardiac pacemakers until serum concentrations decrease
55
What is hypomagnesemia defined as?
<1.5mg/dL
56
What are the neuromuscluar sx associated with hypomagnesemia?
Hyperreflexia/tetany Tremors seizures
57
What are the cardiac sx associate with hypomagnesemia?
Tachycardia Ventricullar fibrillation Torsade de pointes EKG changes: increased PR interval and OT interval; prolonged QRS
58
What are other clinical presentations of hypomagnesemia?
Metabolic alkalosis Hypocalcemia Digoxin toxicity Strong relationship between hypo-K+ and hypo-Mg
59
What are the inadequate intake causes of hypomagnesemia?
ETOH | Dietary restriction
60
What are the inadequate absorption causes of hypomagnesemia?
Steatorrhea cancer malabsorption syndrome excessive ca or P in GI tract
61
What are the excessive GI loss causes of hypomagnesemia?
Diarrhea Laxative abuse NG suctioning Acute pancreatitis
62
What are the excessive urinary loss causes of hypomagnesemia?
Primary hyperaldosteronism DKA Renal disease
63
What are the medication causes of hypomagnesemia?
``` Aminoglycosides AmphoB Cisplatin Insulin Loop and thiazide diuretics Cyclosporin ```
64
What is the treatment for hypomagnesemia?
Magnesium concentration doesn’t correlate with body stores; administer empirically Magnesium Intravenous magnesium sulfate Oral magnesium
65
Magnesium
IV route if severe (1.0 mEq/L) and symptomatic
66
IV magnesium sulfate
Avoid rapid bolus injection – associated with flushing and sweating Dilute administration to avoid pain and venosclerosis IM injection painful; use only if peripheral access nor available Major limitation, even in face of severe depletion, 50% of IV dose immediately cleared by kidneys Need to gradually replace deficit over days
67
Oral magnesium
- MOM (milk of magnesia), Mg2+-containing antacids, magnesium oxide - These are all drugs that are given for constipation. - Diarrhea main limiting factor - Frequent dosing required due to small quantity of magnesium in products - Reduce dose with renal insufficiency
68
What is calciums role and where is it found?
99% total body calcium in bone <1% ECF and ICF Role in transmission of nerve impulses, skeletal muscle contraction, myocardial contractions, maintenance of cellular permeability and formation of bones and teeth
69
What does serum caclium have a reciprocal relationship with?
Reciprocal relationship between serum Ca and serum phosphate concentration that is regulated by complex interaction between parathyroid hormone, Vit D, and calcitonin ½ protein bound and ½ free ionized form
70
How is hypercalcemia defined?
>10.2 mg/dL
71
What is the clinical presentation of acute hypercalcemia?
Inability to concentrate urine Acute renal failure Coma Ventricular arrhythmias
72
What are the sx associated with chronic hypercalcemia?
Metastatic calcification Nephrolithiasis Chronic renal insufficiency
73
What are the causes of hypercalcemia?
``` Hyperparathyroidism Malignancy Paget’s disease Granulomatous diseases (TB, sarcoidosis) Hyperthyroidism Immobilization; multiple bony fractures Acidosis Meds ```
74
What are the medication causes of hypercalcemia?
``` Thiazide diuretics Estrogens Lithium Tamoxifen VIt A and D Calcium supplements ```
75
What is the treatment for hypercalcemia if the condition involves life-threatening sx, functioning kidneys?
Saline rehydration, loop diuretics, hemodialysis, calcitonin, glucocorticoids, IV PO4 if low
76
What is the treatment for hypercalcemia if the condition involves life-threatening symptoms and renal failure?
Hemodialysis, calcitonin, glucocorticoids
77
What is the treatment for hypercalcemia if the condition involves non-life threatening sx and >12 mg/dL?
Saline rehydration, loop diuretics, calcitonin (gets the calcium into the bone), glucocorticoids, IV bisphosphonate (wont work quickly), mithramycin Still treat the patient but can treat them slower
78
What is the treatment for hypercalcemia if the condition involves being asymptomatic and >12 gm/dL?
Observe, correct reversible causes
79
In hypercalcemia what might vomiting cause and how do you fix it?
Vomiting and inability to concentrate urine may cause dehydration and intravascular depletion NS rehydration therapy 200-300 ml/hr initially, decrease to maintenance rate (e.g., 100 ml/hr) after volume status improved
80
Loop Diuretics- In treating hypercalcemia
- Initiate after rehydration completed - MOA: inhibits Ca2+ reabsorption from thick ascending LOH - Prevent volume overload that may occur with NS rehydration - 40-80 mg furosemide IV q 1 to 4 hours - Monitor for hypokalemia and hypomagnesemia
81
Calcitonin- In treating hypercalcemia
- hormone that counters effects of PTH - Inhibits osteoclast activity; promotes renal excretion of calcium - onset 1-2 hours - unpredictable effects - Tachyphylaxis- sudden decrease in a drug response after administration
82
Glucocorticoid- In treating hypercalcemia
- interference with Vitamin D metabolism - prednisone 40 to 60 mg/day - slow onset - many ADRs - add to calcitonin to prolong effect
83
Phosphates- In treating hypercalcemia
Phosphates- doesn’t work very good minimally effective in chronic treatment calcium-phosphorus crystals may precipitate in tissue
84
What is the long term therapy hypercalcemia?
oral phosphates if hyperparathyroid glucocorticoids Bisphosphonate Bottom two are good long term therapy options
85
If a patient is asymptomatic and hypoalbuminemic with hypercalcemia what do you treat with?
No tx is required
86
How do you calculate a corrected serum total calcium?
Corrected Ca= serum calcium + 0.8 * (NL albumin - Pt’s albumin) If the corrected calcium concentration is within the reference range, no treatment is needed
87
What is hypocalcemia defined as?
<6.5 mg/dL
88
What is the clinical presentation for hypocalcemia?
Neuromuscular- tetany, muscle cramps Cardiovascular- hypotension, decreased contractility, heart failure CNS-seizures, areflexia Other-rickets, osteomalacia
89
What are the inadequate intake causes of hypocalcemia?
Vitamin D deficiency | ETOH
90
What are the excessive losses causes of hypocalcemia?
Hypoparathyroidism, renal failure, alkalosis, pancreatitis
91
What are the medication causes of hypocalcemia?
Phosphate replacement products, loop diuretics, phenytoin, phenobarbital, corticosteroids, aminoglycosides
92
What is the treatment for acute symptomatic hypocalcemia?
-Bolus with 100 to 300 mg of elemental calcium IV over 5 to 10 minutes 1 g chloride or 2 to 3 grams of gluconate salt -Continuous infusion of 0.5 to 2 mg/kg/hr, decrease to 0.3 to 0.5 mg/kg/hr elemental Ca2+ after improvement of serum calcium -Monitor serum calcium every 4 to 6 hours
93
What is the IV administration treatment for hypocalcemia?
- Rate NTE 60 mg/min to avoid cardiac ADR - Do not add to bicarbonate or phosphate containing solutions-may cause precipitation - Calcium gluconate causes less phlebitis - Calcium chloride requires smaller volume and more ionized fraction available
94
How is hypocalcemia treated after acute sx are treated?
-Correct contributing electrolyte abnormalities -Oral calcium 1 to 3 grams per day elemental in divided doses ADR: hypercalciuria, nephrolithiasis treat patients at risk for stones with thiazides Vitamin D as needed individualize dose may need to use active Vitamin D 1,25-dihydroxyvitamin D3
95
Where is phosphorus found?
Primarily in bone (80-85%); ICF 15-20%; ECF (1%) Major anion Distribution doesn’t reflect total body stores
96
How is hyperphoshatemia defined?
>4.5mg/dL
97
What are the signs of hyperphosphatemia due to?
Signs of hyperphosphatemia are due to hypocalcemia and precipitation of salt crystals deposition of crystals in joints, soft tissue, kidney
98
When is crystal formation likely to occur in hyperphosphatemia?
Crystal formation is likely to occur when product of the serum calcium and phosphate concentrations exceed 50-60
99
What are the impaired secretion causes of hyperphosphatemia?
Renal failure | Hypoparathyroidism
100
What are the redistribution to ECF causes of hyperphosphatemia?
Acid-base imbalance (the body will redistribute from the bone into the ECG and ICF). Rhabdomyolysis, tumor lysis during chemo
101
What are the increase intake causes of hyperphosphatemia?
Due to medications | P containing enemas and supplements, Vit D supplements, bisphosphonates
102
What is the treatment for hyperphosphatemia?
Severe symptomatic IV calcium salts Less severe oral phosphate binders to decrease GI absorption These would be able to bind to the phosphorus and keep it in the GI for excretion rather than allowing it to be into the serum Ca2+, Mg2+, Al3+ salts
103
What is hypophosphatemia defined as?
<2.5mg/dL
104
What are the CNS sx associated with hypophosphatemia?
Seizures
105
What are muscle weakness sx associated with hypophosphatemia?
Diaphragm muscle fatigue and failure Decreased cardiac contractility Skeletal muscle weakness
106
What are the increased distribution to ICF causes of hypophosphatemia?
Hyperglycemia, insulin therapy, malnutrition
107
What are the decreased absorption causes of hypophosphatemia?
Starvation, excessive use of p-binding antacids (absorbs phosphate), Vit D deficiency, diarrhea, laxative abuse
108
What are the increased renal loss causes of hypophosphatemia?
DKA (getting insulin therapy), ETOH, diuretic use, burns, hyperparathyoidism
109
What are the medication causes of hypophosphatemia?
Diuretics, antacids, foscarnet, phenytoin, phosphate binders, calcium acetate
110
What clinical situations should you be aware of where hypophosphatemia might occur?
Alcoholism Diabetic ketoacidosis treatment Glucose infusion Refeeding syndrome
111
What are the treatments for hypophosphatemia if its severe and symptomatic?
Severe (<1 mg/dL) and symptomatic (true no matter what to cause is) IV phosphorous 0.25 mmol/kg lean body weight Infuse over 4 to 6 hours to avoid precipitation
112
What are the treatments for hypophasphatemia if its moderate?
Moderate (1 to 2.5 mg/dL) Oral phosphorous 1.5 to 2.0 grams (50-60 mmol) per day in 3 to 4 divided doses Doses recommended in many drug references are often inadequate to replete, repeated doses and higher doses often needed
113
What should you consider with treatment for hypophosphatemia?
-Reduce doses in renal insufficiency -Add larger dose than standard dose in TPN or glucose-containing solution if refeeding syndrome a concern Monitor serum phosphorous, magnesium, potassium and calcium -Monitor serum phosphorous every 6 hours during first 48 to 72 hours after starting therapy