Insulin and potassium

 Q: Insulin overdose is a frequent cause of hypokalemia in ICU?

A) True

B) False

Answer: B

It is true that insulin is used in the immediate management of hyperkalemia but it rarely causes hypokalemia if given in excess. Although it may cause hypoglycemia. The objective of this question is to highlight the role of insulin in the treatment of hyperkalemia. 

 Insulin treats hyperkalemia by increasing the entry of potassium at two major sites i.e., skeletal muscles and hepatic cells. At the bedside, this trick may not work if a patient has liver insufficiency or low muscle mass, which frequently co-exists. The entry of potassium is by the increased activity of Na-K-ATPase pump due to insulin. This activity is further enhanced if the body receives exogenous insulin but it rarely causes hypokalemia even if the insulin dose is excessive (see reference # 2).

Despite the above fact, care should be taken in close monitoring of potassium during the management of Diabetic-Keto-Acidosis (DKA) and the associated clinical conditions.

#endocrinology

References:

1. Mount DB, Zandi-Nejad K. Disorders of potassium balance. In: Brenner and Rector's The Kidney, 8th ed, Brenner BM (Ed), WB Saunders Co, Philadelphia 2008. p.547. 

2. Bradberry SM, Vale JA. Disturbances of potassium homeostasis in poisoning. J Toxicol Clin Toxicol 1995; 33:295.