4.2 - Electrolyte Imbalances Flashcards
4 Types of Electrolyte Imbalances
1) Hyperkalemia
- too much K in intravascular space
2) Hypokalemia
- too little K in intravascular space
3) Hypernatremia
- too much Na in intravascular space
4) Hyponatremia
- too little Na intravascular space
Function of Potassium
- range: 3.5-5
- maintains heart and muscle contraction
- excreted by kidneys
Cause of Hyperkalemia
1) Excessive intake
2) Decreased excretion
3) Intracellular to Extracellular movement
- K moves from cells into blood
Pathogenesis of Hyperkalemia
- in early stages, there is an increased excitability of cells; bc the resting membrane potential is less negative and thus easier to fire an AP
- in late stages, there is decreased excitability; bc persistent depolarization can deactivate Na channels that are needed to generate an AP
Clinical Significance of Hyperkalemia
1) Cardiac contractility
- in early stages, bc there is potential for increased excitability, it can also cause tachycardia and palpitations
- in later stages, bc deactivated Na channels = bradycardia
2) Musculoskeletal Impairment
- EALRY: twitches and tingling (paraesthesia), ↑ reflexes
- LATE: numbness, ↓ reflexes
3) Organ Function
- EARLY: hyperactive bowel sounds (diarrhea)
Cause of Hypokalemia
1) Increased K excretion
2) Inadequate K intake
3) Extracellular to intracellular movement
- K is shifted out of bloodstream and into cells
Pathogenesis
Early: decreased excitability of cells
- resting potential is more negative (hyperpolarized)
- cell is further from threshold to generate AP
Clinical Significance of Hypokalemia
1) Cardiac contractility
- palpitations and dizziness
- fucks with hearts coordinated contractions
2) Musculoskeletal Impairment
EARLY: tingling (paraesthsia), muscle weakness
LATE: numbness, flaccid paralysis (loss of muscle tone)
3) Organ Function
- EARLY: hypoactive bowel sounds
- bowel obstruction
- paralytic ileus: loss of normal peristalsis
Function Of Na
- range: 135-145mol/L
- dominant in extracellular fluid
- controls fluid distribution
Cause of Hypernatremia (too much Na)
1) Decrease excretion of Na (kidney dysfunction, meds)
2) Excessive Intake
3) Dehydration
- not enough water, means too much Na
4) Hyperaldosteronism
- excessive aldosterone = fluid retention
Pathogenesis of Hypernatremia
- too much Na means not enough water
- cell shrinks
- ↓ blood volume
Structural Alterations
- Shrinkage of organs; bc a lot of Na means not enough water
Clinical Significance of Hypernatremia
EARLY: polydipsia (excessive thirst), muscle weakness
LATE: ↓ LOC, seizures, coma
- dry mucous membranes, ↓ skin turgor
Causes of Hyponatremia
1) Increased Na excretion
2) Decreased Na intake
3) Excessive water intake or retention
4) SIADH secretion
- body produces excesses ADH which promotes water retention
Pathogenesis of Hyponatramia
- too little Na means too much water
- too much water = cell swelling
- ↑ blood volume
