Hyperkalemia

Hyperkalemia in ChildrenWe all can take things for granted. Certainly I do all of the time: like Gravity, or that a post-menarche female will have a urinary pregnancy test done, or that the kid with altered mental status will have a finger stick glucose level. Unfortunately, when you aren’t explicit, important issues can be missed. For instance, in the past we have discussed several important conditions that can be associated with a life threatening electrolyte derangement (ex, Rhabdomyolysis, Congenital Adrenal Hyperplasia, Massive PRBC transfusion, Failure to Thrive, Hypertensive CrisisSinus Bradycardia), but we weren’t explicit about one of the fundamental and critical treatment plans. Let’s rectify this oversight by reviewing the management of Hyperkalemia in Children:

 

Hyperkalemia: Basics

  • Potassium (K+) is required for normal transmembrane voltage gradients. (ugh, remember that in class?) [Long, 2018]
    • Particularly important in muscle and nerve cells!
    • All muscle cells (skeletal, cardiac, smooth) use the voltage gradients for action potentials.
  • Hyperkalemia is commonly encountered.
    • ~10% of all patients admitted from the ED. [Long, 2018]
    • Moderate to severe hyperkalemia was found in 12% of PICU patients. [Cummings, 2014]
  • Hyperkalemia can develop due to:
    • Decreased Excretion
    • K+ Shift to Vascular Compartment
    • Exogenous Source 
      • Medications (especially if concurrent renal impairment)
        • ACE Inhibitors
        • Potassium-Sparing Diuretics
          • Spironolactone
          • Triamterene
          • Trimethoprim-sulfamethoxazole (oh, look, another reason to not like bactrim).
          • Yasmin (birth control)
        • NSAIDs
      • K+ containing IV Fluids! (good old fashioned iatrogenic hyperkalemia!)
      • Hyperkalemia from increased intake of K+ is rare if kidneys are functional. (So eat all of those bananas!)
    • Spurious Lab Error
      • Especially an issue in children.
      • Hemolysis found in 24% of hyperkalemic results in PICU patients. [Cummings, 2014]
      • Tiny catheters, tight tourniquets, fists being cleanched, and samples that are “milked” out of the patient will potentially lead to hemolysis in the test tube and cause artificially elevated K+ level. [Long, 2018]

 

Hyperkalemia: Symptoms

  • Symptoms are NOT reliable to determine who requires therapy.
    • Symptoms can be vague.
      • Weakness, Fatigue, Paresthesias, Diarrhea
    • Can be dramatic also – Paralysis, Decreased DTRs
  • The main concern is the critical symptom of cardiac dysrhythmia!

 

Hyperkalemia: Management

  • See an elevated K+ level… check that Blood Pressure!
    • May require a manual BP reading.
    • May help you discern whether a child has undiagnosed renal disease. [Hollander, 2016]
  • Potassium level is important, but not the deciding factor.
    • Often texts will described Hyperkalemia as Mild, Moderate, and Severe. [Long, 2018]
      • Mild – 5.5-6.5 mEq/L
      • Mod – 6.5-7.5 mEq/L
      • Sev – > 7.5 mEq/L
    • Often the levels that “define” these categories differ between references.
    • The rate at which the K+ level is changing may be more important the the absolute level.
    • Management decision based on K+ level alone is not advised. [Long, 2018]
  • The ECG is useful, but not the entire story.
    • ECG manifestations include:
      • Peaked T waves
      • PR prolongation, decreased P wave amplitude
      • QRS widening, increased R wave amplitude
      • Loss of P waves
      • Conduction blocks (AV blocks, LBBB, RBBB)
      • Sine Wave
      • Asystole
      • Sinus Bradycardia
      • And anything “Bizarre” looking – Amal Mattu taught me that!
    • Often ECG manifestations are taught as occurring in a step-wise fashion as the K+ level increases…
      • This is not the case. [Long, 2018]
      • A patient can progress from normal ECG to v-fib.
      • ECG changes are more common when the K+ level is changing rapidly.
    • ECG findings should not be the sole determinant of management plans. [Long, 2018]
  • Treatments for Hyperkalemia are effective and have few side effects. [Long, 2018]
    • Stablize Cardiac Membranes
      • Should give first! They works quickly and can save a life.
      • Calcium: [Long, 2018]
        • Calcium Chloride
          • Has 13.6 mEq of Ca+ in 10 mL
          • Can be caustic (ie, necrosis, thrombophlebitis) to peripheral vessels.
          • Use via Central Access or during a Code (“C”hloride for Codes and Central lines)
        • Calcium Gluconate
          • Has 4.6 mEq of Ca+ in 10 mL
          • Friendly on peripheral veins, but lower Ca+ amount makes Chloride preferred if having cardiac ectopy… or you can give 3 times the amount of Ca+ gluconate.
        • Calcium onset = < 3 min
        • Calcium duration = 20-60 min (so, it buys you some time… but you may need to re-dose)
      • Hypertonic Saline: [Long, 2018]
    • Redistribute K+ into the Cells
      • Beta-Agonists
        • 10 – 20 mg of Albuterol can be nebulized and will decrease K+ in 15-30 min.
        • Duration = ~90 min.
        • Can also use IV terbutaline.
      • Insulin & Glucose
        • Insulin reliably lowers plasma K+ levels.
          • IV Regular insulin (0.1 U/kg up to 10 Units) is often used in a bolus. [Wheeler, 2016]
          • Onset of action = 15 min
          • Duration = 4-6 hrs.
          • Short-acting synthetic insulins (ex, Lispro, Insulin Aspart) may have some benefits over Regular Insulin.
            • Have shorter-half-lives and more rapidly absorbed.
            • Decreased risk for hypoglycemia
            • They are also not eliminated by kidneys, so they don’t hang around if patients with renal impairment.
        • Concern for hypoglycemia is significant! [Schafers, 2012]
          • Dose of glucose is usually given with the insulin, but insulin activity will often outlast the glucose stores.
          • Be paranoid about causing hypoglycemia. Give more than you think you need and check it often!
        • Giving insulin is difficult in children and takes time. [Arnholt, 2015]
          • It requires serial dilutions and lots of math.
          • Give other therapies first because of this.
    • Remove the K+
      • Diuretics +/- IV Fluids
        • For patient with functional kidneys who is hypervolemic or euvolemic, loop diuretics (furosemide) can be a great option. [Long, 2018]
        • If patient is hypovolemic, giving IV fluids alone can also help.
      • Dialysis
        • If patient with severe hyperkalemia or in patient without functional kidneys, the dialysis is the only real option.
  • There is often debate and confusion about treatment strategies. [Chime, 2015]
    • Certainly whether to treat or not treat is made easy when the patient is critically ill, but when they appear well with vague symptoms it can be challenging.
    • Don’t be cavalier always blaming the K+ in kids on the fact it was a “difficult stick.”
    • Membrane stabilizers may afford you time to sort out the details.
  • Treatment Controversies
    • Sodium Bicarbonate
      • Many treatment strategies include sodium bicarb (including ACLS).
      • In theory, alkalinization can lead to H+ and K+ exchange.
      • In practice, sodium bicarbonate does not significantly decrease K+ when pH is normal. [Long, 2018]
      • It may be helpful in the patient with metabolic academia. [Long, 2018]
    • Sodium Polystyrene Sulfonate
      • We are often asked to give this medicine.
      • I’ll be blunt, it is NOT a medicine that will be useful in the ED. [Long, 2018; Kovesdy,2017; Cochrane, 2005]
      • It is likely not useful at all.
      • It may be harmful (ex, bowel obstruction, bowel necrosis).
      • Novel potassium binders may eventually replace this defunct medicine. [Long, 2018; Kovesdy, 2017]
        • Patiromer – non absorbable synthetic polymer
        • ZS-9 – non absorbable cation exchanger that binds 9 times the amount of K+ compared to sodium polystyrene sulfonate.

 

Moral of the Morsel

  • It’s not always a Lab Error. What are the risk factors for this being real? Double check that level, but some empiric therapy may be reasonable while awaiting confirmation.
  • Consider the Whole picture. Don’t just rely on ECG or K+ level.
  • Review those Medications and Fluids. Iatrogenic causes are all around.
  • Triple your Gluconate! You can give as much elemental Ca+ as calcium chloride with 3 times the amount of calcium gluconate.
  • Don’t waste time with things that don’t help. Save the sodium bicarb for the TCA overdose. Don’t kill the gut with a medicine that doesn’t work.

 

References

Long B1, Warix JR2, Koyfman A3. Controversies in Management of Hyperkalemia. J Emerg Med. 2018 Aug;55(2):192-205. PMID: 29731287. [PubMed] [Read by QxMD]

Garcia J1,2, Pintens M2, Morris A2, Takamoto P2, Baumgartner L2,3, Tasaka CL2,4. Reduced Versus Conventional Dose Insulin for Hyperkalemia Treatment. J Pharm Pract. 2018 Sep 6:897190018799220. PMID: 30189765. [PubMed] [Read by QxMD]

Kovesdy CP1,2. Updates in hyperkalemia: Outcomes and therapeutic strategies. Rev Endocr Metab Disord. 2017 Mar;18(1):41-47. PMID: 27600582. [PubMed] [Read by QxMD]

Wheeler DT1, Schafers SJ2, Horwedel TA2, Deal EN2, Tobin GS3. Weight-based insulin dosing for acute hyperkalemia results in less hypoglycemia. J Hosp Med. 2016 May;11(5):355-7. PMID: 26762588. [PubMed] [Read by QxMD]

Lee J1,2, Moffett BS3,4. Treatment of pediatric hyperkalemia with sodium polystyrene sulfonate. Pediatr Nephrol. 2016 Nov;31(11):2113-7. PMID: 27215929. [PubMed] [Read by QxMD]

Hollander R1, Mortier G2, van Hoeck K3. Hyperkalemia in young children: blood pressure checked? Eur J Pediatr. 2016 Dec;175(12):2011-2013. PMID: 27639857. [PubMed] [Read by QxMD]

Chime NO1, Luo X, McNamara L, Nishisaki A, Hunt EA. A survey demonstrating lack of consensus on the sequence of medications for treatment of hyperkalemia among pediatric critical care providers. Pediatr Crit Care Med. 2015 Jun;16(5):404-9. PMID: 25734786. [PubMed] [Read by QxMD]

Arnholt AM1, Duval-Arnould JM, McNamara LM, Rosen MA, Singh K, Hunt EA. Comparatively Evaluating Medication Preparation Sequences for Treatment of Hyperkalemia in Pediatric Cardiac Arrest: A Prospective, Randomized, Simulation-Based Study. Pediatr Crit Care Med. 2015 Sep;16(7):e224-30. PMID: 26181299. [PubMed] [Read by QxMD]

Lepage L1, Dufour AC1, Doiron J1, Handfield K1, Desforges K1, Bell R1, Vallée M2, Savoie M1, Perreault S3, Laurin LP2, Pichette V4, Lafrance JP5. Randomized Clinical Trial of Sodium Polystyrene Sulfonate for the Treatment of Mild Hyperkalemia in CKD. Clin J Am Soc Nephrol. 2015 Dec 7;10(12):2136-42. PMID: 26576619. [PubMed] [Read by QxMD]

Cummings BM1, Macklin EA2, Yager PH1, Sharma A3, Noviski N4. Potassium abnormalities in a pediatric intensive care unit: frequency and severity. J Intensive Care Med. 2014 Sep-Oct;29(5):269-74. PMID: 23753253. [PubMed] [Read by QxMD]

Schafers S1, Naunheim R, Vijayan A, Tobin G. Incidence of hypoglycemia following insulin-based acute stabilization of hyperkalemia treatment. J Hosp Med. 2012 Mar;7(3):239-42. PMID: 22489323. [PubMed] [Read by QxMD]

Sterns RH1, Rojas M, Bernstein P, Chennupati S. Ion-exchange resins for the treatment of hyperkalemia: are they safe and effective? J Am Soc Nephrol. 2010 May;21(5):733-5. PMID: 20167700. [PubMed] [Read by QxMD]

Sean M. Fox

I enjoy taking care of patients and I finding it endlessly rewarding to help train others to do the same. I trained at the Combined Emergency Medicine and Pediatrics residency program at University of Maryland, where I had the tremendous fortune of learning from world renown educators and clinicians. Now I have the unbelievable honor of working with an unbelievably gifted group of practitioners at Carolinas Medical Center. I strive every day to inspire my residents as much as they inspire me.

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1 Response

  1. Lee says:

    Thanks for the morsel’s !! I (almost) always learn something, and very much enjoy your writing style…
    Please don’t stop.

    Lee

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