Fluid and Electrolyte Disorders (Part 2) Flashcards
Which electrolytes are highly regulated by kidneys, need prominent renal reabsorption, and are large intracellular concentrations?
K+ and Mg 2+
Which electrolytes have large bony deposits and are regulated by vitamin D and the parathyroid hormone (PTH)?
Ca 2+ and Phosphate
Normal serum K+ levels
3.5 - 5 mEq/L
Define hypokalemia
< 3.5 mEq/L
What are the main causes of hypokalemia?
- Intracellular shifting
- Total body deficit
- Hypomagnesemia
In hypokalemia patients, why does intracellular shifting happen?
- Metabolic alkalosis
- Drugs: albuterol, insulin, theophylline
In hypokalemia patients, why does total body deficit happen?
- Poor intake of dietary potassium
- Excessive loss due to renal (diuretics, amphotericin B) or extra-renal (vomiting, diarrhea)
(T/F) - The clinical presentation of hypokalemia can be variable and independent on the degree of hypokalemia
FALSE - it’s variable and DEPENDENT on the degree of hypokalemia
What are some symptoms from hypokalemia?
- Muscle cramping/impaired muscle contractions
- Severe EKG changes: ST segment depression or flattening
- Cardiac arrhythmias (heart block, ventricular fibrillation)
If patient has hypokalemia, what is the first treatment option?
Treat underlying cause
If the patient has mild (3.0 - 3.5 mEq/L) hypokalemia, what is the best treatment?
Oral K+ supplements
What is a main adverse effect from oral K+ supplements?
GI upset (to reduce, give patient < 20 mEq of K+)
Once hypomagnesemia has been treated in hypokalemia patients and they’re asymptomatic, what should be given for treatment?
Oral K+ supplements
Once hypomagnesemia has been treated in hypokalemia patients and they’re symptomatic, what should be given for treatment?
IV K+ replacements
What are the types of IV K+ replacements given to hypokalemic patients?
Peripheral line
Central line
The maximum dose for a central line K+ replacement in hypokalemic patients is…
20 mEq/hr
The maximum dose for a peripheral line K+ replacement in hypokalemic patients is…
10 mEq/hr
(T/F) For every 10 mEq given to a patient raises their serum K+ levels ~0.1 mEq/L
TRUE
Define hyperkalemia
> 5.0 mEq/L
What are the main causes of hyperkalemia?
- Extracellular shifting
- Increased intake
- Decreased output
In hyperkalemia patients, why does extracellular shifting happen?
Metabolic acidosis
In hyperkalemia patients, why does increased intake happen?
- Exogenous [K+ supplement; salt substitutes (DASH)]
- Endogenous [hemolysis, burns, muscle crush injuries]
In hyperkalemia patients, why does decreased output happen?
- Renal failure (acute or chronic)
- Drugs: TMP/SMX, ACEi/ARBs, NSAIDs, K+ sparring diuretics
(T/F) - Hyperkalemic patients are typically symptomatic
False - typically asymptomatic
What are some symptoms from hyperkalemia?
- Palpitations
- Skipped heart beats
- Weakness
- Bradycardia
Do life-threatening arrhythmias occur in hyperkalemia? If so, at what serum K+ level?
Yes, > 6.0 mEq/L
Before starting pharmacological treatments for hyperkalemic patients, what should be done?
Treat underlying disease
If the patient has mild (5.5 - 6.0 mEq/L) hyperkalemia, what pharmacological treatment can be given?
- Sodium polystyrene sulfonate
- Furosemide IV
(T/F) - Sodium polystyrene can be given to patients who have constipation
FALSE - contraindicated in constipated patients
If the patient has moderate/severe (> 6.0 mEq/L) hyperkalemia who is symptomatic, what pharmacological treatment should be given first?
Patient experiencing severe cardiac arrhythmias - administer calcium gluconate IV
After symptoms have been controlled from moderate/severe hyperkalemia, what other pharmacologic treatment can be given?
- Insulin
- Albuterol
What are the normal serum Mg 2+ levels?
1.5 - 2.2 mEq/L
Define hypomagnesemia
< 1.5 mEq/L
What are the causes of hypomagnesemia?
- Diet
- GI sources
- Renal sources
- Hypoparathyroidism
- Hyperaldosteronism