Episode 189: Hyperkalemia 2.0

We revisit the topic of Hyperkelamia to update our prior episode from 2015 (pre-Lokelma)

Hosts:

Brian Gilberti, MD

Jonathan Kobles, MD

https://media.blubrry.com/coreem/content.blubrry.com/coreem/Hyperkalemia.mp3

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Tags: Renal Colic

Show Notes

Introduction

Background

Physiology:

Normal range and the significance of deviations (>5.5 mEq/L)

Epidemiology:

Prevalence of hyperkalemia in the ER

ESRD missed HD → ECG, monitor

Causes / Risk Factors

Causes

Kidney Dysfunction, Medications, Cellular Destruction, Endocrine Causes, Pseudohyperkalemia

High-Risk Medications:

Antibiotics: Bactrim, antifungals

Calcineurin inhibitors

Beta-blockers

ACE/ARB

K+ Sparing diuretics

NSAIDs

Digoxin

SUX – high risks in neuromuscular disease

Lab errors, hemolysis in samples

VBG vs Chem accuracy

When to repeat a hemolyzed sample

2023 study: Of the 145 children with hemolyzed hyperkalemia, 142 (97.9%) had a normal repeat potassium level. Three children (2.1%) had true hyperkalemia: one had known chronic renal failure and was referred to the ED due to concern for electrolyte abnormalities; the other 2 patients had diabetic ketoacidosis (DKA).

Clinical Presentation / eval

Symptomatic vs. Asymptomatic:

“First symptom of hyperkalemia is death”

If severe, ascending muscle weakness → paralysis

Point at which patients experience symptoms depends on chronicity

>7 mEq/L if chronic and can be lower if acute

Hyperkalemia can be a cause of non-specific GI symptoms

EKG Changes:

ECG findings may be the first marker the ER doc gets that something is wrong

Typical changes:

Peaked T-waves, shortened QT

Lengthening of PR interval and QRS duration

Bradycardia / Junctional rhythm

Hyperkalemia can produce bradycardia without other ECG findings

Ones associated with VT/VF/code, death in one study: QRS widening (RR = 4.74), Junctional Rhythm (RR = 7.46), HR <50 (RR = 12.29) while no adverse outcomes with just peaked T waves or PR prolongation (Durfey, 2017)

Don’t be fooled by a normal ECG, may be normal, but it’s also on case report level to have K > 9 and a normal ECG

Series of 127 patient (K 6-9.3), no serious arrhythmia noted, only 46% had ECG changes, (Acker, 1998)

ECG changes are not linear, there is no exact association between K+ levels and ECG changes

ECG changes may be hidden and subtle in patients with underlying inter-ventricular conduction delay (BBBs)

Be suspicious of the patient with LBBB > 160 ms or RBBB > 140 ms

BRASH Syndrome

Synergism between hyperkalemia, renal failure/injury and AV nodal blocking agents -> may produce ECG changes out of proportion to serum potassium levels.

Labs

Chem, VBG, +/- CK if you think muscle breakdown is at play (Tintinalli talks about looking at urine K, but this is not most people’s practice)

Consider evaluation for adrenal insufficiency

Waiting for labs may not be an option

Renal dysfunction + consistent ECG findings → prompt treatment before chem results

Realistically 2 hours to get back chemistry in most settings ≈ eternity

Management in the ER

Discontinue/hold any nephrotoxins or medications in suspected medication-induced hyperkalemia

A. Acute Management Strategies:

Cardiac protection with calcium

1g over 5-10 mins

Lasts 30-60 mins, may have to redose

Dose considerations if on digoxin

AEs: Calciphylaxis and hypercalcemia

Fast pushes can result in hypotension, arrhythmia

Calcium chloride vs calcium gluconate

Caution in patients taking Digoxin

IVF choice – NS vs LR

Caution/Avoid fluid in patients with ESRD/CHF or signs of VOL

Shifting potassium:

insulin/glucose

5 units vs 10 units

5 similar effect, less hypoglycemic episodes (LaRue 2017)

If doing 10 units, start D10W at 50-75 cc/h after amp of d50 but be mindful that anuric patient who missed HD may not have much room for volume

Decrease but about 0.5-1.2 mEq/L

Effect starts 10-20 mins after administration and can last 4-6 hours

Albuterol

10-20 mg over 10 mins (