Hyperkalemia

Question 1

What is the clinical definition of hyperkalemia?

Answer 1

Serum potassium levels greater than 5 mEq/L

Question 2

What is the potassium level range associated with peaked T waves on an ECG?

Answer 2

5.5–6.5 mmol/L

Question 3

What ECG changes occur at a potassium level of 5.5–6.5 mmol/L?

Answer 3

Peaked T waves (due to repolarization abnormalities).

Question 4

What potassium level is associated with progressive atrial paralysis on ECG?

Answer 4

6.5–7.0 mmol/L

Question 5

What ECG changes occur at potassium levels of 6.5–7.0 mmol/L?

Answer 5

progressive atrial paralysis = gradual disappearance of P waves

P wave widening and flattening

PR prolongation

eventual disappearance of P waves.

Question 6

At what potassium level does muscle weakness, conduction abnormalities and bradyarrhythmias appear?

Answer 6

7.0–9.0 mmol/L

Question 7

What are the key ECG changes associated with potassium levels of 7.0–9.0 mmol/L?

Answer 7

Bradyarrhythmias (sinus bradycardia, AV block, slow junctional/ventricular escape rhythms), conduction blocks, prolonged QRS interval with bizarre QRS morphology.

Question 8

What potassium level is associated with pre-terminal ECG findings, such as a sine wave appearance?

Answer 8

Greater than 9.0 mmol/L

Question 9

What ECG findings are seen at potassium levels above 9.0 mmol/L?

Answer 9

Sine wave appearance, asystole, ventricular fibrillation, and PEA with bizarre, wide-complex rhythms.

Question 10

What increases the risk of hyperkalemia?

Answer 10

Renal:
- Acute or Chronic kidney disease
- decreased effective circulating volume (ECV) causing low distal solute delivery
- decreased aldosterone from RTA type 4 (hyporeninemic-hypoaldosteronism)
- decreased aldosterone from Addisons disease
- decreased aldosterone from ACEi or ARB use
- resistance to aldosterone from K-sparing diuretics

Rhabdomyolysis

Insulin deficiency

Beta-Blockers

Metabolic or respiratory acidosis (swopping K for H on albumin)

Question 11

What is the first step in managing hyperkalemia?

Answer 11

IV Calcium Gluconate

IV Insulin with D5W

Question 12

What are the second-line medications for hyperkalemia?

Answer 12

Beta-agonist (albuterol)

Sodium Bicarbonate

Question 13

What must be done to definitively treat hyperkalemia?

Answer 13

Dialysis

• can give diuretics if the renal function is good *
• K-binding resins has been shown to cause GI necrosis *