ELECTROLYTE QUIZ

The answer is A. The patient has cardiotoxicity from hyperkalemia. Protection by calcium is needed immediately, followed by some approach to reduce plasma potassium. Kayexalate is contraindicated because of its effect on bowel - colonic necrosis and because it will take too long to work.

The Question
A 68 year old African American male patient on chronic dialysis comes into the hospital with nausea and vomiting that began 6 hours previously. The patient has mild abdominal bloating and some mild tenderness in the epigastrium and peri-umbilical area, but there is no guarding or rebound. No bowel sounds are heard. The patient has labs drawn and the serum potassium is 7.2 mEq/L. His electrocardiogram is shown below. All of the following would be reasonable next steps, except:

A.) Treatment with Kayexalate 30 grams with 30 cc's of sorbitol

B.) 10 mEq of calcium gluconate immediately

C.) Calcium gluconate and 10 units of soluble insulin and 50 grams of dextrose IV

D.) Medical treatment with calcium gluconate IV and immediate hemodialysis

Explanation: Management of hyperkalemia

1. If K>5.5 mEeq/L, do an ECG to look for cardiotoxicity of the hyperkalemia. If present: intravenous calcium.

2.) Enhance potassium uptake by cells.

a.) Insulin and dextrose.

b.) Beta-adrenergic agonists. In the United States, the most commonly used preparation is nebulized albuterol. The dose for treating hyperkalemia, 10 mg, is substantially higher than the usual dose for the treatment of bronchospasm and requires the assistance of a respiratory therapist.

3.) Increase potassium excretion from the body.

a.) Cation exchange resins. Sodium polystyrene sulfonate (SPS) or Kayexalate either orally or rectally (as a retention enema). The onset of action occurs <2 hours and is long lasting. However, note that Kayexalate should be avoided in patients with GI symptoms. Sterns in JASN: “In September 2009, the US Food and Drug Administration (FDA) posted safety labeling changes for Kayexalate powder on its web site. The warning reads, “Cases of colonic necrosis and other serious gastrointestinal adverse events (bleeding, ischemic colitis, perforation) have been reported in association with Kayexalate use. The majority of these cases reported the concomitant use of sorbitol. Concomitant administration of sorbitol is not recommended. At the same time, evidence has grown that mixtures of resin in sorbitol may be harmful. By 2005, the FDA had received 35 adverse event reports of serious bowel injuries associated with both oral and rectal administration of the mixture, many of them fatal. Extensive transmural infarction of the colon and ileum was observed with SPS crystals adherent to the mucosa and in luminal debris.”

b.) Emergency dialysis. Very effective especially in chronic dialysis patients.