Potassium D2

Question 1

Loss of potassium in GI tract

Answer 1

-Diarrhea:
Large amounts of potassium are in intestinal fluids so diarrhea can cause potassium depletion
-Vomiting
-Fistulas 
-NG suction

Question 2

Loss of potassium through kidneys

Answer 2

Sometimes too much potassium is excreted in urine - usually because of drugs that cause the kidneys to excrete excess sodium, water, and potassium (diuretics - thiazide).
Magnesium depletion
Hyperaldosteronism

Question 3

Loss of potassium through skin:

Answer 3

Diaphoresis

Question 4

Shift of K into cells:

Answer 4

Increased insulin (eg. IV dextrose load)
Alkalosis
Tissue repair
Increase epinephrine (eg. stress)

Question 5

Clinical Manifestations Hypokalemia

Answer 5

-Muscle weakness
-Lethargy
-Anorexia
-Dysrhythmia
-Cardiac arrest (if severe)
-Nausea
-Fatigue
-Hyperglycemia
-Weak irregular pulse
-Paresthesias (numbness & tingling)
-Decreased bowel motility
If prolonged:
Inability of kidneys to concentrate urine (causing dilute urine) - which leads to nocturia, polyuria and excessive thirst
-Potassium depletion depresses the release of insulin and results in glucose intolerance

Question 6

Normal pH of blood

Answer 6

7.35-7.45

Question 7

Acidosis: occurs when pH?

Answer 7

occurs when pH of plasma falls below 7.35 -

- associated w/ increased plasma K concentration (hyperkalemia)

Question 8

Alkalosis: occurs when pH?

Answer 8

plasma pH above 7.45 -

- associated w/ reduced plasma K concentration (hypokalemia)

Question 9

Potassium balance is critical for many cellular and metabolic functions including:

Answer 9

• Nerve conduction
• Normal cardiac electrical conduction (for heart contractions)
• Skeletal and smooth muscle contraction
• Intracellular osmolality and cellular growth
• Role in acid-base balance as often reciprocal exchange of K-H across cell membrane

Question 10

Hypokalemia happens when?

Answer 10

K < 3.5 mmol/L

Question 11

Hyperkalemia happens when?

Answer 11

K > 5.0 mmol/L

Question 12

What supplement or diuretics causes hyperkalemia and what is the mechanism of action?

Answer 12

Potassium-sparing diuretics (Spironolactone) –

Blocks reabsorption of Na and reduce secretion of K (Na - K exchange) = can result in hyperkalemia

Question 13

What can cause failure to eliminate K?

Answer 13

• ACE inhibitors
• Renal disease
• Potassium sparing diuretics
• Adrenal insufficiency

Question 14

Shift of K out of cells

Answer 14

• Acidosis
• Tissue catabolism
• Crush injury
• Tumour lysis syndrome

Question 15

Clinical Manifestations Hyperkalemia

Answer 15

-Ventricular dysrhythmias
-Cardiac arrest
-Skeletal muscle weakness
(Rapidly ascending muscular weakness can lead to flaccid quadriplegia)
-Muscle twitching
-Fatigue
-Paresthesias (numbness and tingling)
-Dyspnea (difficult or labored breathing.)
-Cramping

Question 16

Serum Sodium and Potassium normal values

Answer 16

Na: 135-145 mmol/L
K: 3.5-5.0 mmol/L

Question 17

Drugs that Raise Potassium

Answer 17

• Potassium Chloride
• IV K additives (KCL) (20-60mmol/L)
• Potassium-sparing diuretics Spironolactone

Question 18

Drugs that Lower Potassium

Answer 18

-Insulin and Glucose (temporary effect, moves K to cell) IV insulin pushes glucose into cell and K goes along
K leaves blood and enters cells
- Polystyrene sulfonate (Kayexalate) (po, rectal) binds to K in bowel and removed in stool
**Exchanges Na ion for K ion in the intestine
**Sometimes given with a laxative the speed up evacuation of K
-Loop diuretic
-Sodium bicarbonate (reduce acidosis, K-H exchange)
**Reduces acidosis by raising the pH of the blood
**Raised pH of blood - decreased plasma K [ ] = lower K levels

Question 19

Drugs that stabilize heart function with ↑K

Answer 19

• Calcium gluconate

- Calcium chloride

Question 20

Treatments that Lower Potassium

Answer 20

• Peritoneal Dialysis (removes K) long-term treatment, need peritoneal tube surgically placed
• Hemo-Dialysis (removes K) can be done urgently, primarily long-term treatment, need vascular access

Question 21

Can Potassium Chloride be given as an IV bolus?

Answer 21

IV Potassium chloride is NEVER given IV push (bolus) because it may be FATAL (cardiac arrest)
(IV Potassium has been used as part of lethal injections in executions)