4.2 - Electrolyte Imbalances

Question 1

4 Types of Electrolyte Imbalances

Answer 1

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

Question 2

Function of Potassium

Answer 2

• range: 3.5-5
• maintains heart and muscle contraction
• excreted by kidneys

Question 3

Cause of Hyperkalemia

Answer 3

1) Excessive intake
2) Decreased excretion
3) Intracellular to Extracellular movement
- K moves from cells into blood

Question 4

Pathogenesis of Hyperkalemia

Answer 4

• 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

Question 5

Clinical Significance of Hyperkalemia

Answer 5

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)

Question 6

Cause of Hypokalemia

Answer 6

1) Increased K excretion
2) Inadequate K intake
3) Extracellular to intracellular movement
- K is shifted out of bloodstream and into cells

Question 7

Pathogenesis

Answer 7

Early: decreased excitability of cells
- resting potential is more negative (hyperpolarized)
- cell is further from threshold to generate AP

Question 8

Clinical Significance of Hypokalemia

Answer 8

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

Question 9

Function Of Na

Answer 9

• range: 135-145mol/L
• dominant in extracellular fluid
• controls fluid distribution

Question 10

Cause of Hypernatremia (too much Na)

Answer 10

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

Question 11

Pathogenesis of Hypernatremia

Answer 11

• too much Na means not enough water
• cell shrinks
• ↓ blood volume

Question 12

Structural Alterations

Answer 12

• Shrinkage of organs; bc a lot of Na means not enough water

Question 13

Clinical Significance of Hypernatremia

Answer 13

EARLY: polydipsia (excessive thirst), muscle weakness

LATE: ↓ LOC, seizures, coma

• dry mucous membranes, ↓ skin turgor

Question 14

Causes of Hyponatremia

Answer 14

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

Question 15

Pathogenesis of Hyponatramia

Answer 15

• too little Na means too much water
• too much water = cell swelling
• ↑ blood volume

Question 16

Structural Alterations

Answer 16

• organs swelling
• can cause ↑ intracranial pressure

Question 17

Clinical Significance of Hyponatremia

Answer 17

Early: headache, nausea, confusion

Late: LOC, seizures, coma

• polydipsia (excessive thrist)

Question 18

Function of Chloride

Answer 18

• involved in blood pressure/volume
• maintains pH

Question 19

Function of Magnesium

Answer 19

• involved in neuromuscular contractility

Question 20

Hypermagnesemia

Answer 20

Symptoms

• bradycardia
• ↓ BP
• weakness
• lethargy, coma

Question 21

Hypomagnesemia

Answer 21

Symptoms

• tachycardia
• ↑ BP
• twitching, paraesthesia
• irritbaility and confusion

Question 22

Function of Ca

Answer 22

• stored in bone
• also involved in neuromuscular contractility
• closely linked to magnesium (if magnesium is low, Ca is low)
• Ca absorption is dependent on vitamin D

Question 23

Causes of Hypercalcemia

Answer 23

> 2.6
1) Increased absorption
2) Decreased excretion
3) increased bone resorption/break down
- Ca is released from bone into blood

Question 24

Pathogenesis of Hyper calcemia

Answer 24

• bone break down releases Ca into blood

Question 25

Structural Changes of Hypercalcemia

Answer 25

** not enough Ca in bones** - osteoporosis - fractures - kidney stones (nephrolithiasis); more Ca is filtered in kidneys and crystallized

Question 26

Clinical Significance of Hypercalcemia

Answer 26

-polyuria - polydipsia (polyuria leads to this) - anorexia - constipation; Ca slows GI motility - fatigue - hypoactive bowel sounds (constipation) Severe: confusion, delirium, coma

Question 27

Causes of Hypocalcemia

Answer 27

1) Low magnesium - low mg = low Ca 2) Excess Ca excretion 3) Inadequate Ca intake

Question 28

Structural Changes of Hypocalcemia

Answer 28

1) Impaired teeth mineralization - ↓ Ca = weaker teeth 2) Osteomalacia - weakened, soft bone tissue 3)Neuromuscular excitability - less Ca means more Na into cells which makes cell hyperactive and more likely to fire AP's

Question 29

Clinical Significance of Hypocalcemia

Answer 29

- paraesthesia - muscle cramps - tetany; involuntary muscle contractions - positive chvostek: contarction of facial muscle in response to tapping - trousseau: carpal spasm from inflating BP cuff

Question 30

Function of Phosphate

Answer 30

- stored in bone and some soft tissue - P and Ca have an inverse relationship - bone and teeth health, RBC function