Potassium

• Most DKA patients are whole body depleted on presentation: average 3 to 5 mEq/kg total body potassium deficit

• During initiation of treatment with insulin the serum potassium concentration can rapidly drop resulting in life threatening cardiac arrhythmias

• Initial hypokalemia ( <3.3 mEq/L ) needs aggressive potassium replacement before insulin therapy is started - treatment with IV potassium until K >3.5 mEq/L

• Initial potassium level >3.3 mEq/L and <5.2 mEq/L needs concurrent potassium replacement with insulin therapy - treatment with IV potassium for at least 4 hrs

• Initial hyperkalemia ( >5.2 mEq/L ) needs fluid replacement and insulin therapy which will often lower the potassium level rapidly

Magnesium

• Osmotic diuresis may cause hypomagnesemia

• If serum magnesium concentration is <2.0 mEq/L or symptoms are present consistent with hypomagnesemia - treat with IV magnesium sulfate 2-4 g IV

Phosphate

• Initially serum phosphate levels are often normal or increased, phosphate then reenters intracellular space during insulin therapy causing hypophosphatemia (most severe 1 to 2 days after initiation of insulin therapy)

• No role for starting phosphate replacemnt in ED for DKA patients unless phosphate concentration <1.0 milligram/dL

REFERENCES:

Tintinalli, JE. Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 8th ed. New York, NY: McGraw-Hill Education LLC, 2016.