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

Redistribution

1. Acidosis drives potassium out of the cells

• DKA

1. Cellular breakdown

• Rhabdomyolysis
• Hemolysis
• Tumor lysis syndrome
• Crush

B. Increased total body potassium

1. Inadequate excretion

a. Renal caused (acute or chronic renal failure-must have GFR<10)

b. Mineralocorticoid deficiency or Addison's disease

c. Drug-induced (potassium sparing diuretics [e.g., spironolactone] and ACE-inhibitors)

2. Excessive intake

a. Diet, meds

b. Blood transfusion

C. Pseudohyperkalemia

1. Hemolysis of the specimen

2. Prolonged period of tourniquets occlusion prior to blood draw

3. Thrombocytosis/leukocytosis

D. Misc

1. Succs, dib, B-blockers

Treatment

• Calcium gluconate 1 amp IV (if ECG changes/hypotension/or >7; can give mult times)
• Caution in dig-toxic patients!
• Albuterol neb 2.5mg x 3
• 10 U reg insulin IV with 1 amp D50W IV now, and 1 amp in 15 min
• 1 amp NaBicarb IV (over 5 min)
• Kayexalate 30g PO (may cause volume overload; +/- 50mL sorbitol)
• Consider dialyisis & ?lasix

Source

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