Hyperkalemia and Hypokalemia- paulson Flashcards
Hyperkalemia: serum potassium is ______
-Is hyperkalemia dangerous?
-> 5.0 mEq/L
**(But there will be some variation in laboratory reference standards)
*Hyperkalemia is a dangerous electrolyte abnormality, potentially leading to life-threatening arrhythmias and death
“emia”=
“condition of the blood”
Hyperkalemia refers to high serum potassium, NOT ____
whole body potassium
Most (___%) of total body potassium is intracellular
-Less than ___% circulates in the bloodstream
Normal serum K of _______mEq/L is tightly regulated by the kidney
- (98%)
- 2%
- 3.5-5.0 =normal
Hyperkalemia: etiology
- Increased intake
- Decreased excretion
- Shift from intracellular to extracellular
- Pseudohyperkalemia
Hyperkalemia:
-describe increased intake
- PO supplementation
- IV potassium
Hyperkalemia:
-describe pseudohyperkalemia
- Mechanical trauma from venipuncture: –>Can see red serum–>Could also be true severe intravascular hemolysis
- Exercise- repeated clenching of the fist during venipuncture
- Cooling of sample or deterioration of sample
- Thrombocytosis
- Severe leukocytosis
Intracellular to Extracellular Shifts: can occur due to (3 things)
- Any breakdown of cells
- acidosis
- Insulin deficiency or resistance
Decreased Excretion (of potassium): describe 3 possible causes
- Renal failure
- Hypovolemia
- Hypoaldosteronsism
Describe Renal failure (how it pertains to decreased K+ excretion)
- Acute or chronic
- Kidneys unable to filter and excrete normally
Describe hypovolemia (how it pertains to decreased K+ excretion)
- Dehydration, CHF, cirrhosis
- Low flow to the kidneys
Describe hypoaldosteronism (how it pertains to decreased K+ excretion)
- Everyone’s FAV lecture ;) remember, aldosterone causes secretion of K+
- RTA4
- Adrenal insufficiency
Intracellular to Extracellular Shifts:
-Describe any breakdown of cells
-Broken cells release potassium when they lyse
- -Crush injuries/major trauma, rhabdo, tumor lysis syndrome after chemo
- -Pseudohyperkalemia
Intracellular to Extracellular Shifts:
-Describe Acidosis
H+ moves from the blood into the cells in exchange for K+
Intracellular to Extracellular Shifts:
-describe Insulin deficiency or resistance
- Insulin causes K+ entry into cells
- -Diabetes (body doesnt make insulin or is non responsive to insulin–> decreased K+ entry into cells)
Meds that can cause hyperkalemia: KNOW!!!
**ACEIs
**ARBs
**NSAIDs
**Spironolactone
Beta blockers
Digitalis
Succinylcholine
**Bactrim
-Amiloride (a diuretic)
Potassium supplements
T/F: hyperkalemia can cause Cardiotoxicity
True!!!
- Hyperkalemia causes cardiotoxicity by ↑ the resting membrane potential of the cardiac myocyte, causing “membrane excitability”
- *At very high levels, potassium causes the depolarization threshold to rise, leading to overall depressed cardiac function
Hyperkalemia:
-clinical features
-May have vague and varied symptoms, but is usually totally asymptomatic
-May have: Nausea/vomiting Palpitations Lethargy Confusion Paresthesias Muscle weakness Paralysis if advanced Arrhythmias/Death
Hyperkalemia:
-labs/eval
- Repeat the potassium level if there’s doubt about its veracity
- Serum potassium will be above 5.0
- BMP to assess renal function
- EKG
- Consider ABG if suspecting acidosis
EKG changes associated with hyperkalemia
**Classic EKG changes (in sequential order):
- Peaked T wave – K 5.5-6.5 mEq/L
- Flattened P wave with prolonged PR interval or totally absent P wave – K 6.5-7.5 mEq/L
- Wide QRS – K 7.0-8.0 mEq/L
- Sine wave pattern portending imminent cardiac arrest K >8.0 mEq/L
- Above does not occur in every patient
EKG findings
image slide 15
When is hyperkalemia considered an emergency?
- Clinical s/s from hyperkalemia–> Most serious: muscle weakness or paralysis, arrhythmias
- Potassium is >6.5
- Moderate hyperkalemia (>5.5) + significant renal impairment +
- -Ongoing tissue breakdown –or-
- -Ongoing potassium absorption –or-
- -Significant acidosis
Hyperkalemia: tx
-If severe hyperkalemia + EKG changes–> tx?
- IV calcium gluconate
- Continuous cardiac monitoring
- Options to drive potassium back into the cell:
Hyperkalemia: tx
-list options to drive potassium back into the cell
- Insulin + glucose
- Beta-2 adrenergic agonists (inhaled albuterol)
- IV sodium bicarbonate–>Temporary, not lasting solutions
Hyperkalemia: tx
-Options for removal of Potassium from the body (list 3)
- GI cation exchanger:
- -Bind K+ in the GI tract in exchange for other cations–> excreted in feces
- -Sodium polystyrene sulfonate (Kayexalate)
- -Patiromer (Veltassa)
- Diuretics: Loop diuretic (ie: Lasix) + saline
- Hemodialysis–> Hyperkalemic Pts with severe renal impairment
Hyperkalemia: tx
-what are some OBVIOUS thoughts regarding tx
Stop any potassium supplements or medications that can increase potassium
Hypokalemia:
-what is the serum potassium?
< 3.5 mEq/L
Hypokalemia: pathophysiology
-describe various mechanisms of K+ loss
-Increased loss:
Renal: Diuretics, Hyperaldosteronism
GI: Vomiting, Diarrhea
- Movement of potassium from blood into intracellular compartment
- Hypomagnesemia
- Renal tubular acidosis
- Meds
- Very LOW calorie diets
Hypokalemia: pathophysiology
-describe the methods of Movement of potassium from blood into intracellular compartment (list 3)
- Insulin excess
- Beta agonist treatment
- Alkalosis
Hypokalemia is often concurrent with _______
**hypomagnesemia
Often concurrent Mg & K+ losses ie: diuretics, vomiting
Describe renal tubular acidosis:
- Type 1=
- Type 2=
Type 1 (distal) & 2 (proximal) can cause potassium wasting
Hypokalemia 2/2 medications (list ex’s)
**Diuretics (except potassium-sparing), amphotericin B, antipsychotics (Risperdal, Seroquel), Barium or chloroquine intoxication
Hypokalemia:
-specify caloric input for low cal diet that can cause hypokalemia
200-800 calories
Hypokalemia:
-clinical features
- No pathognomonic presenting s/s
- May have muscle fatigue or weakness
- Often starts in LE, progresses to the trunk/UE, can end in paralysis
- **Cramps, rhabdomyolysis, and myoglobinuria
- Respiratory muscle weakness
- GI muscle involvement
Respiratory muscle weakness (seen in some Pts w/ hypokalemia) can lead to _____
**respiratory failure/death
Hypokalemia:
-describe GI muscle involvement
ileus, constipation, n/v
Hypokalemia:
-diagnostic tests (list 3)
- **BMP
- Magnesium
- EKG
Hypokalemia:
-associated EKG changes
May have:
- **Flattened or inverted T waves
- **More prominent U waves–> Often seen in leads V4-V6
- ST depression
- Prolonged QT interval “QU interval”
- Arrhythmia
Hypokalemia: K+ of ___
1.7
Hypokalemia: tx
- Usually not emergent unless there are cardiac manifestations or K+ level is <2.5
- Give IV potassium replacement in this situation–> Can cause pain & phlebitis
-Oral potassium chloride preferred for most others
Hypokalemia: tx
-if concurrent hypomagnesemia–>
also needs to be repleted
Hypokalemia: tx
-what needs to be continuously monitored?
Needs continuous cardiac monitoring and frequent recheck of K+ level
