Hyperkalemia

Severity

Bands from the UK Kidney Association, which uses the European Resuscitation Council definition.¹ No single treatment threshold is agreed in US emergency practice.² For potassium, 1 mmol/L equals 1 mEq/L.

First 10 minutes

1. Monitor and get a 12-lead ECG. Get an ECG for any potassium ≥ 6.0. Use continuous cardiac monitoring for ≥ 6.5, for any ECG changes, or for 6.0–6.4 in a patient who is unwell or whose level is rising.¹
2. Confirm fast. Run potassium on a blood gas analyzer while the lab result is pending.¹ A high level with a normal ECG should raise the question of a spurious result.¹⁹
3. ECG changes or instability: give IV calcium now.^1,19
4. Shift: insulin with glucose, plus nebulized albuterol for severe hyperkalemia.¹
5. Plan removal and find the cause. Start a binder. In anuric or dialysis patients, call for dialysis early.^19,1
6. Recheck potassium at 1, 2, 4, 6 and 24 hours, aiming for < 6.0 within 2 hours. Follow the glucose schedule below.¹

ECG

Typical changes are peaked T waves, flattened P waves with a longer PR interval, a widening QRS, and finally a sine wave and arrest. They do not always appear in that order, and several can appear at once.¹ See the LITFL ECG library for more examples.¹⁷

Single-center retrospective study. Adverse events (mostly symptomatic bradycardia) occurred in 15% of patients. Every patient who had one also had at least one hyperkalemic finding on the preceding ECG.³

The ECG is insensitive. In 90 admitted patients with potassium ≥ 6, the ECG missed many cases, and readers agreed only moderately. The authors advise managing by the clinical picture and serial potassium levels, not by the ECG alone.⁴

Treatment

All potassium values in mEq/L. Combined, insulin-glucose and albuterol lower potassium about 0.7–1.2 mEq/L (low to very low certainty).⁵

Binders

• In ED patients (n = 70), adding SZC to insulin-glucose gave a larger drop at 2 hours (−0.72 vs −0.36 mEq/L). At 4 hours the difference was small and not statistically clear (−0.41 vs −0.27).¹⁴
• In outpatients (mean K 5.6), SZC brought potassium to normal in a median of 2.2 hours.¹⁵
• In adults aged 66 and older, Kayexalate was associated with roughly double the risk of a serious GI event within 30 days (HR 1.94). The absolute numbers were small.¹⁶
• Loop diuretics can help patients who still make urine and are volume replete. This advice comes from the chronic-management section of the UK guideline.¹

Avoiding hypoglycemia

• Who is at risk: patients without diabetes, a low pre-treatment glucose, female sex, low body weight, and renal dysfunction.^13,12
• When it happens: in dialysis patients, at a median of 2 hours after insulin, lasting a median of 2 hours.¹² Across 62 studies, the median onset was 124 minutes.¹ Many patients have left your attention by then.
• Check glucose at 0, 30, 60, 90, 120, 180, 240, 300 and 360 minutes after insulin.¹
• Pre-treatment glucose under 126 mg/dL (7 mmol/L): run D10 at 50 mL/h for 5 hours after the bolus.¹

Dialysis patients

• Dialyze urgently at K ≥ 6.5.¹
• Give calcium for toxic ECG changes even when dialysis is immediately available.¹
• Use standard medical therapy while waiting. Up to 40% of patients with end-stage renal disease do not respond to albuterol.¹
• Expect potassium to rebound after a dialysis session.¹

Cardiac arrest

Give calcium chloride when hyperkalemia is known or suspected as the cause. This is a weak recommendation (grade 2C).¹ The ILCOR review found no evidence that calcium improves clinical outcomes.⁵

Pseudohyperkalemia

A falsely high result is common. REBEL EM calls it the leading cause of a high potassium.¹⁹ Suspect it when renal function and the ECG are normal, or when the patient has a blood disorder.¹

• Causes: delayed or cold transport, difficult draws, hemolysis, high platelet counts, erythrocytosis, EDTA carry-over from the wrong order of draw, and drawing from an arm with a potassium-containing infusion.¹
• Confirm it with paired lithium-heparin (plasma) and clotted (serum) samples from a large vein. A serum value more than 0.4 above the plasma value confirms pseudohyperkalemia.¹

Causes

• Reduced excretion: renal failure. Drugs include ACE inhibitors, ARBs, spironolactone, NSAIDs, and trimethoprim.^19,1
• Shift out of cells: acidosis, succinylcholine, and digoxin toxicity.^19,6
• Cell death: tumor lysis, rhabdomyolysis, burns, crush injury, and hemolysis.¹⁹

Disposition

• Severe (≥ 6.5) and stable: admit to a bed with continuous cardiac monitoring.¹
• Airway, breathing, circulation or consciousness problems: refer to critical care.¹
• Refractory to medical therapy: nephrology or critical care decides urgently on renal replacement therapy.¹
• Found incidentally in a well patient: recheck mild levels within 3 days and moderate levels within 1 day. Assess severe levels in hospital.¹

Pitfalls

• Ordering "one amp" of calcium gluconate gives a third of the guideline dose.^1,19
• Giving albuterol at asthma doses. Hyperkalemia needs 10–20 mg.^7,19
• Handing off or discharging before the glucose low point, around 2 hours after insulin.¹²
• Being reassured by the absence of peaked T waves. Watch the QRS, the rate, and the rhythm.³
• Missing the rebound. Shifted potassium comes back as treatment wears off, so recheck at 4 and 6 hours.¹
• Using milk of magnesia or Fleet enemas, which risk magnesium and phosphate toxicity.²⁰

How strong is the evidence?

Almost every acute treatment rests on low or very low certainty evidence.⁵ Calcium is supported mainly by physiology and case reports.¹ Insulin dosing data are retrospective.⁹ The expert panel convened by the American College of Emergency Physicians calls the common drugs temporizing at best.²

On-shift teaching

Questions to ask a learner at the bedside. Tap a question to see the answer. Every answer uses facts cited above.

References

1. 1
   Alfonzo A, Harrison A, Baines R, et al. Clinical Practice Guidelines: Treatment of Acute Hyperkalaemia in Adults. UK Kidney Association; updated July 2026.Guidelineukkidney.orgFull text read
2. 2
   Rafique Z, Peacock F, Armstead T, et al. Hyperkalemia management in the emergency department: an expert panel consensus. JACEP Open. 2021;2(5):e12572.ConsensusPMID 34632453PMCPubMed
3. 3
   Durfey N, Lehnhof B, Bergeson A, et al. Severe hyperkalemia: can the electrocardiogram risk stratify for short-term adverse events? West J Emerg Med. 2017;18(5):963–971.CohortPMID 28874951PMCPubMed
4. 4
   Montague BT, Ouellette JR, Buller GK. Retrospective review of the frequency of ECG changes in hyperkalemia. Clin J Am Soc Nephrol. 2008;3(2):324–330.CohortPMID 18235147PMCPubMed
5. 5
   Jessen MK, Andersen LW, Djakow J, et al.; ILCOR. Pharmacological interventions for the acute treatment of hyperkalaemia: a systematic review and meta-analysis. Resuscitation. 2025;208:110489.Meta-analysisPMID 39761907PubMed
6. 6
   Levine M, Nikkanen H, Pallin DJ. The effects of intravenous calcium in patients with digoxin toxicity. J Emerg Med. 2011;40(1):41–46.CohortPMID 19201134PubMed
7. 7
   Allon M, Dunlay R, Copkney C. Nebulized albuterol for acute hyperkalemia in patients on hemodialysis. Ann Intern Med. 1989;110(6):426–429.RCTPMID 2919849PubMed
8. 8
   LaRue HA, Peksa GD, Shah SC. A comparison of insulin doses for the treatment of hyperkalemia in patients with renal insufficiency. Pharmacotherapy. 2017;37(12):1516–1522.CohortPMID 28976587PubMed
9. 9
   Moussavi K, Garcia J, Tellez-Corrales E, Fitter S. Reduced alternative insulin dosing in hyperkalemia: a meta-analysis of effects on hypoglycemia and potassium reduction. Pharmacotherapy. 2021;41(7):598–607.Meta-analysisPMID 33993515PubMed
10. 10
    Moussavi K, Nguyen LT, Hua H, Fitter S. Comparison of IV insulin dosing strategies for hyperkalemia in the emergency department. Crit Care Explor. 2020;2(4):e0092.CohortPMID 32426734PMCPubMed
11. 11
    Wheeler DT, Schafers SJ, Horwedel TA, Deal EN, Tobin GS. Weight-based insulin dosing for acute hyperkalemia results in less hypoglycemia. J Hosp Med. 2016;11(5):355–357.CohortPMID 26762588PubMed
12. 12
    Apel J, Reutrakul S, Baldwin D. Hypoglycemia in the treatment of hyperkalemia with insulin in patients with end-stage renal disease. Clin Kidney J. 2014;7(3):248–250.CohortPMID 25852884PMCPubMed
13. 13
    Moussavi K, Fitter S, Gabrielson SW, Koyfman A, Long B. Management of hyperkalemia with insulin and glucose: pearls for the emergency clinician. J Emerg Med. 2019;57(1):36–42.ReviewPMID 31084947PubMed
14. 14
    Peacock WF, Rafique Z, Vishnevskiy K, et al. Emergency potassium normalization treatment including sodium zirconium cyclosilicate: a phase II randomized, double-blind, placebo-controlled study (ENERGIZE). Acad Emerg Med. 2020;27(6):475–486.RCTPMID 32149451PMCPubMed
15. 15
    Kosiborod M, Rasmussen HS, Lavin P, et al. Effect of sodium zirconium cyclosilicate on potassium lowering for 28 days among outpatients with hyperkalemia: the HARMONIZE randomized clinical trial. JAMA. 2014;312(21):2223–2233.RCTPMID 25402495PubMed
16. 16
    Noel JA, Bota SE, Petrcich W, et al. Risk of hospitalization for serious adverse gastrointestinal events associated with sodium polystyrene sulfonate use in patients of advanced age. JAMA Intern Med. 2019;179(8):1025–1033.CohortPMID 31180477PMCPubMed
17. 17
    Life in the Fast Lane. Hyperkalaemia ECG library.FOAMlitfl.comLink checked
18. 18
    Life in the Fast Lane. Calcium, digoxin toxicity and "stone heart" theory.FOAMlitfl.comLink checked
19. 19
    Swaminathan A. REBEL Core Cast 125.0: Hyperkalemia. REBEL EM; June 26, 2024.FOAMrebelem.comPage read
20. 20
    Emergency Medicine Cases. Episode 86: Hyperkalemia. 2016.FOAMemergencymedicinecases.comLink checked
21. 21
    Farkas J. Hyperkalemia. Internet Book of Critical Care, EMCrit; July 2024. Further reading; not used for any claim above.FOAMemcrit.orgNot machine-checked (site disallows automated access)