09-06-2014, 12:28 PM
This patient likely has spurious hyperkalemia due to underlying essential thrombocytosis (ET). ET is a rare clonal disorder of unclear etiology. Hemorrhagic and thrombotic complications have been reported. The gastrointestinal tract is a common site for hemorrhage and thrombosis of the duodenal arcade arteries. Lysis of the large number of platelets results in hyperkalemia, which is a laboratory artifact. However, if a plasma (rather than serum) potassium level is checked, the result is normal and will help confirm the diagnosis.
A is not correct. 26% chose this.
Intravenous sodium bicarbonate can shift potassium into cells. Ideally, this treatment should be reserved for severe hyperkalemia associated with metabolic acidosis. Administration of intravenous calcium gluconate decreases cardiac membrane excitability and is useful in the setting of hyperkalemia with ECG changes. However, these measures are recommended in severe hyperkalemia when ECG abnormalities are present.
B is not correct. 22% chose this.
Hyperkalemia is defined as a plasma potassium level >5.0 mEq/L. Potentially fatal hyperkalemia rarely occurs unless the plasma potassium level is >7.5 mEq/L, and it is usually associated with profound weakness and QRS widening, absent P waves, or ventricular arrhythmias on ECG. Insulin causes a shift of potassium into cells. However, this patient does not have true hyperkalemia or ECG changes suggestive of hyperkalemia.
C is not correct. 19% chose this.
Oral sodium polystyrene sulfonate is a cation exchange resin that facilitates the exchange of sodium for potassium in the gastrointestinal tract. Each gram binds 1 mmoL of potassium and releases 2-3 mmoL of sodium. However, this patient does not have true hyperkalemia, and thus oral sodium polystyrene sulfonate would not be appropriate.
E is not correct. 9% chose this.
Measuring the urine potassium level can help in the diagnostic approach to hyperkalemia. A urine potassium level 40 mEq/L usually indicates a nonrenal etiology. While measuring the urine potassium level in this patient this would point us in the correct direction, it would not confirm the diagnosis.
Bottom Line:
Essential thrombocytosis may cause spurious hyperkalemia. Always check an ECG before initiating treatment to lower elevated potassium levels.
A is not correct. 26% chose this.
Intravenous sodium bicarbonate can shift potassium into cells. Ideally, this treatment should be reserved for severe hyperkalemia associated with metabolic acidosis. Administration of intravenous calcium gluconate decreases cardiac membrane excitability and is useful in the setting of hyperkalemia with ECG changes. However, these measures are recommended in severe hyperkalemia when ECG abnormalities are present.
B is not correct. 22% chose this.
Hyperkalemia is defined as a plasma potassium level >5.0 mEq/L. Potentially fatal hyperkalemia rarely occurs unless the plasma potassium level is >7.5 mEq/L, and it is usually associated with profound weakness and QRS widening, absent P waves, or ventricular arrhythmias on ECG. Insulin causes a shift of potassium into cells. However, this patient does not have true hyperkalemia or ECG changes suggestive of hyperkalemia.
C is not correct. 19% chose this.
Oral sodium polystyrene sulfonate is a cation exchange resin that facilitates the exchange of sodium for potassium in the gastrointestinal tract. Each gram binds 1 mmoL of potassium and releases 2-3 mmoL of sodium. However, this patient does not have true hyperkalemia, and thus oral sodium polystyrene sulfonate would not be appropriate.
E is not correct. 9% chose this.
Measuring the urine potassium level can help in the diagnostic approach to hyperkalemia. A urine potassium level 40 mEq/L usually indicates a nonrenal etiology. While measuring the urine potassium level in this patient this would point us in the correct direction, it would not confirm the diagnosis.
Bottom Line:
Essential thrombocytosis may cause spurious hyperkalemia. Always check an ECG before initiating treatment to lower elevated potassium levels.