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

1. Redistribution

• Acidosis drives potassium out of the cells (e.g. DKA)

2. Cellular breakdown

• Rhabdomyolysis
• Hemolysis
• Tumor lysis syndrome
• Crush

3. Increased total body potassium

• Inadequate excretion
  • Renal caused (acute or chronic renal failure-must have GFR<10)
  • Mineralocorticoid deficiency or Addison's disease
  • Drug-induced (potassium sparing diuretics [e.g., spironolactone] and ACE-inhibitors)
• Excessive intake
  • Diet, meds
  • Blood transfusion

4. Pseudohyperkalemia

• Hemolysis of the specimen
• Prolonged period of tourniquets occlusion prior to blood draw
• Thrombocytosis/leukocytosis

5. Misc

• Sux, dig, B-blockers

Treatment

1) Calcium gluconate 1 amp IV (if ECG changes/hypotension/or >7; can give mult times)

Can also give Ca Gluconate 1 amp (but dissociates more slowly and must give more volume)

• Caution in dig-toxic patients!*

2) Albuterol neb 2.5mg x 3

3) 10 U reg insulin IV with 1 amp D50W IV now, and 1 amp in 15 min

4) 1 amp NaBicarb IV (over 5 min)

5) Kayexalate 30g PO (may cause volume overload; +/- 50mL sorbitol)

    -or rectal 50g enema

• 6) Consider dialyisis (& ?lasix 20-40mg IVP)

Source

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