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Monday, January 26, 2015

Fast Facts on Hyperkalemia

excess potassium, hyperkalemia, electrolyte, nurse


Fast Facts on Hyperkalemia

Potassium is a very important electrolyte. Having too little or too much is a BIG problem. This post is about having too much. I'll discuss the causes, the clinical signs, and the treatments of hyperkalemia.
In case you missed it, yesterday's post was on HYPOkalemia. You might want to also check that one out. Quick Guide to Hypokalemia

Overview

Ok. Let's jump in! Potassium is needed in the transmission of nerve impulses, muscle contractions, creating tissues, breaking down carbohydrates, and maintaining intracellular acid - base balance.

The normal level for potassium is 3.5 - 5 mEq/L. Hyperkalemia is when you have an excess of potassium so your level is greater than 5 mEq/L. 

Heads up if you haven't already made the connection but "hypo" means too little. "Hyper" means too much. You'll see it a lot with electrolytes and the endocrine system.

Causes of Hyperkalemia


Just like hypokalemia the imbalance in hyperkalemia is often secondary to another issue. It's not typically as easy as too little or too much intake of potassium. 

  • Oliguric renal failure- If renal clearance is low then you'll have a decreased excretion of potassium, so it builds up in the body and leads to hyperkalemia.
  • Potassium-Conserving Diuretics- You really need to read my post on hypokalemia and the Renin-Angiotensin-Aldosterone system. With potassium-sparing diuretics (ex: Spironolactone) you are mucking around with the body's ability to excrete potassium. It's important to educate your patients on lowering their ingestion of potassium while they are on these drugs. Also, the risk for hyperkalemia goes up significantly if they are taking an ACE inhibitor as well as a potassium-sparing diuretic.
  • Hypoaldosteronism- A deficiency in aldosterone will cause sodium loss and potassium retention. So Hypoaldosterone and Addison's disease will put patients at risk for developing hyperkalemia.
  • Excessive use of oral potassium supplements
  • Excessive use of salt substitutes- Salt substitutes are potassium just in case you didn't know. While these are great for people who need to lower their salt intake they are contraindicated for someone with renal disease.
  • Rapid IV administration of potassium- Rate does not exceed 10 mEq/hr. Peripheral Vein: Concentration of KCl maxes out at 40 mEq/L. Central Vein: Concentration is to not exceed 100 mEq/L
  • Rapid transfusion of aged blood
  • Acidosis- Potassium leaks out of cells during acidosis.
  • Tissue damage (such as a crush injury)- When the injury occurs, the damage causes potassium to leak out of cells.
  • Malignant cell lysis after chemotherapy- Same as with crush injuries, potassium leaks out of cells as they are destroyed. 

Clinical Signs/Manifestations of Hyperkalemia

  • Vague Muscular Weakness
  • Flaccid Muscle Paralysis
  • Paresthesia
  • Tall, Peaked T Waves- earliest signs of changes in cardiac conduction show up around 6 mEq/L. Tall, peaked T waves will happen first.
  • Widened QRS Complex- Happens after the patient has tall, peaked T waves. The heart rate slows down.
  • Ventricular Arrythmias- May occur at any point when potassium levels are high.
  • Cardiac Arrest- May occur at any point when potassium levels are high.
  • Nausea
  • Diarrhea

Treatment

  • Restriction of potassium intake- decrease intake of foods with potassium, stop using potassium-sparing diuretics, stop using potassium supplements, stop ingesting salt substitutes.
  • Dialysis
  • Calcium Gluconate- Calcium will immediately antagonize potassium in the myocardial induction system. Onset is nearly immediate.
  • Loop Diuretics- Increases the excretion of potassium. Onset is 30 minutes to an hour. Note that this won't help patients that have renal problems.
Ok. Let that sink in.

Since you've read this article you might be interested in also reading:
Renin-Angiotensin-Aldosterone System Explained

Everything a Nurse Needs to Know About Diuretics

Overview of Hypernatremia

Overview of Hyponatremia

Do you have any questions? Is there something else you'd like for me to post about?? Leave a comment for me or shoot me an email. I'll be happy to help!

Xoxo,

Nightingale

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