Hyperkalemia

Background

High = >5.5meq/L High! = >6.5meq/L

Diagnosis

Always consider pseudohyperkalemia (e.g. from hemolysis)

ECG

6.5 - peaked Ts, inc PR, dec QT

7.5 - QRS widening, P flattening

8 - sine wave, v-fib, heart block

Differential Diagnosis

A. Increased potassium release from cells

• 1. Pseudohyperkalemia
  • a. Hemolysis of specimen
  • b. Leukocytosis and thrombocytosis
    • 1. K+ increases by 0.15 meq for every 100,000 elevation in plt count
• 2. Metabolic Acidosis
  • a. Drives potassium out of cells
• 3. Insulin deficiency
• 4. Hyperosmolality
• 5. Cellular breakdown
  • a. Rhabdomyolysis
  • b. Hemolysis
  • c. Tumor lysis syndrome
  • d. Crush

B. Reduced urinary potassium excretion

• 1. Renal failure - must have GFR <10
• 2. Aldosterone deficiency
  • a. Addison's disease
  • b. ACEI
• 3. Aldosterone resistance
  • a. Diuretics - Amiloride, spironolactone, triamterene
  • c. Drug-induced (potassium sparing diuretics [e.g., spironolactone] and ACE-inhibitors)
• 4. Hypoperfusion
• 5. Excessive intake
  • a. Diet, meds
  • b. Blood transfusion

C. Misc

• 1. Sux, digoxin overdose, B-blockers (only significant cause if pt also has renal failure)

Treatment

• 1. Calcium Gluconate 1 amp IV
  • a. Give only if ECG changes/hypotension/or >7
  • b. Can give multiple times
  • c. Can also give CaCl 1 amp (but can lead to calcium toxicity)
  • d. Caution in dig-toxic patients!
  • e. Effect begins within minutes, lasts 30-60 minutes

• 2. Albuterol neb 10mg in 4mL saline over 10 min
  • a. Peak effect within 90 min
  • b. Lowers K ~ 0.5-1.5
• 3. Reg insulin 10 U IV with 1 amp D50W IV now, and 1 amp in 15 min
  • a. Effect begins in 10-20 min, peaks at 30-60 min, lasts 4-6 hours
  • b. Lowers K ~ 0.5 - 1.2
• 4. Bicarbonate
  • a. Controversial
  • b. NaBicarb 1 amp IV (over 5 min)
• 5. Kayexalate 30g PO or 50g PR (may cause hypernatremia and volume overload)
• 6. Dialyisis

Source

7/2/09 Adapted from Tintinalli, Donaldson, Pani