Hyperkalemia

Question 1

What can predispose a patient to hyperkalemia?

Answer 1

• Acute renal failure, extensive burns, trauma, or severe rhabdomyolysis or severe acidosis. Acute digoxin toxicity and adrenal insufficiency.
• MCC missed dialysis

Question 2

When do symptoms in hyperkalemia present?

Answer 2

Only in severe hyperkalemia do symptoms develop, with cardiovascular, neuromuscular, and gastrointestinal effects being seen

Weakness is the most common symptom

Cardiovascular is the most common affected system. 2nd or 3rd degree heart block, wide complex tachycardias, and progression to ventricular fibrillation and systole.

Other symptoms: gastrointestinal effects such as nausea, vomiting, and diarrhea or more commonly, neuromuscular effects, including muscle cramps, generalized weakness, paresthesias, tetany, and focal or global paralysis.

Question 3

Definition of hyperkalemia

Answer 3

> 5.5 mEq/L

Question 4

What are the most common causes of hyperkalemia?

Answer 4

Most common cause is lab error from hemolysis.

Then pseudohyperkalemia resulting from thrombocytosis, leukocytosis or erythrocytosis. Hyperkalemia in the chronic renal failure patient is the most common cause of true hyperkalemia in the emergency department.

Question 5

EKG changes based on K level

Answer 5

K 6.5-7.5 mEq/L Peaked T waves
K 7.5-8.0 mEq/L Widening of QRS, decreased amplitude of P waves
K 10-12mEq/L Sine wave, ventricular fibrillation, asystole

Question 6

What is the initial treatment with hyperkalemia when you need to stabilize the myocardium?

Answer 6

Calcium gluconate 10ml (1 ampule) IV over 2-5 minutes. This dose may be repeated after 5 minutes if no improvement. Onset within minutes, and lasts approximately 30-45 minutes

Question 7

Common ways to shift potassium

Answer 7

• Regular insulin 10-20 units IV, combined with Dextrose (D50 50 ml) if the serum glucose is less than 250 mg/dL. Onset 15 minutes, duration 4-6 hours
• Albuterol 2.5-10mg Nebulized. Onset 30 minutes, duration 2-3 hours.
• Sodium bicarb (not regarded as affective)
• Kayexalate – binding resin that exchanges sodium for potassium in the colon, onset 1-2 hours, duration 4-12 hours.
• Furosemide 20-40 mg IV, onset 15 minutes to 1 hour, duration approximately 4 hours. May enhance renal excretion of potassium in patients with preserved renal function.
• Hemodialysis – indicated if hemodynamically unstable.