Hypokalemia is a common electrolyte abnormality found in pediatric patients. The cut off for low potassium is based on age, with young infants having higher baseline levels of potassium when compared to older children and adults. The most common cause of hypokalemia in children is GI losses (diarrhea), though other considerations include malnutrition, congenital adrenal hyperplasia, renal abnormalities and medication effects.
Typically, hypokalemia is well tolerated, and the focus of management is based on treating the underlying cause, rather than repleting the potassium.
Medications should ONLY be initiated in patients who have potassium levels < 3.0 mmol/L OR with those with levels < 3.5 mmol/L with ECG changes.
In patients receiving treatment, oral potassium administration is typically recommended unless any of the following criteria are met:
Potassium level < 2.5 mmol/L
Inability to tolerate PO
There are any ECG changes concerning for hypokalemia
In these patients IV potassium should be given (typically KCl at 0.5-1mEq/kg/DOSE - Max of 40 mEq/dose).
Just like in adults, ALL patients require continuous cardiac monitoring when receiving potassium infusions.
References
Brown DH, Paloian NJ. Hypokalemia/Hyperkalemia and Hyponatremia/Hypernatremia. Pediatr Rev. 2023 Jul 1;44(7):349-362. doi: 10.1542/pir.2021-005119. PMID: 37391630.
