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Following the Hyperkalemia Trail: A Case Report of ECG Changes and Treatment Responses
Following the Hyperkalemia Trail: A Case Report of ECG Changes and Treatment Responses
Hyperkalemia involves elevated serum potassium levels (> 5.0 mEq/L) and represents an important electrolyte disturbance due to its potentially severe consequences, including cardiac effects that can lead to dysrhythmia and even asystole and death.1,2 In a US Medicare population, the prevalence of hyperkalemia has been estimated at 2.7% and is associated with substantial health care costs.3 The prevalence is even more marked in patients with preexisting conditions such as chronic kidney disease (CKD) and heart failure.4,5
Hyperkalemia can result from multiple factors, including impaired renal function, adrenal disease, adverse drug reactions of angiotensin-converting enzyme inhibitors (ACEIs) and other medications, and heritable mutations.6 Hyperkalemia poses a considerable clinical risk, associated with adverse outcomes such as myocardial infarction and increased mortality in patients with CKD.5,7,8 Electrocardiographic (ECG) changes associated with hyperkalemia play a vital role in guiding clinical decisions and treatment strategies.9 Understanding the pathophysiology, risk factors, and consequences of hyperkalemia, as well as the significance of ECG changes in its management, is essential for health care practitioners.
Case Presentation
An 81-year-old Hispanic man with a history of hypertension, hypothyroidism, gout, and CKD stage 3B presented to the emergency department with progressive weakness resulting in falls and culminating in an inability to ambulate independently. Additional symptoms included nausea, diarrhea, and myalgia. His vital signs were notable for a pulse of 41 beats/min. The physical examination was remarkable for significant weakness of the bilateral upper extremities, inability to bear his own weight, and bilateral lower extremity edema. His initial ECG upon arrival showed bradycardia with wide QRS, absent P waves, and peaked T waves (Figure 1a). These findings differed from his baseline ECG taken 1 year earlier, which showed sinus rhythm with premature atrial complexes and an old right bundle branch block (Figure 1b).
Medication review revealed that the patient was currently prescribed 100 mg allopurinol daily, 2.5 mg amlodipine daily, 10 mg atorvastatin at bedtime, 4 mg doxazosin daily, 112 mcg levothyroxine daily, 100 mg losartan daily, 25 mg metoprolol daily, and 0.4 mg tamsulosin daily. The patient had also been taking over-the-counter indomethacin for knee pain.
Based on the ECG results, he was treated with 0.083%/6 mL nebulized albuterol, 4.65 Mq/250 mL saline solution intravenous (IV) calcium gluconate, 10 units IV insulin with concomitant 50%/25 mL IV dextrose and 8.4 g of oral patiromer suspension. IV furosemide was held due to concern for renal function. The decision to proceed with hemodialysis was made. Repeat laboratory tests were performed, and an ECG obtained after treatment initiation but prior to hemodialysis demonstrated improvement of rate and T wave shortening (Figure 1c). The serum potassium level dropped from 9.8 mEq/L to 7.9 mEq/L (reference range, 3.5-5.0 mEq/L) (Table 1).
In addition to hemodialysis, sodium zirconium 10 g orally 3 times daily was added. Laboratory test results and an ECG was performed after dialysis continued to demonstrate improvement (Figure 1d). The patient’s potassium level decreased to 5.8 mEq/L, with the ECG demonstrating stability of heart rate and further improvement of the PR interval, QRS complex, and T waves.
Despite the established treatment regimen, potassium levels again rose to 6.7 mEq/L, but there were no significant changes in the ECG, and thus no medication changes were made (Figure 1e). Subsequent monitoring demonstrated a further increase in potassium to 7.4 mEq/L, with an ECG demonstrating a return to the baseline of 1 year prior. The patient underwent hemodialysis again and was given oral furosemide 60 mg every 12 hours. The potassium concentration after dialysis decreased to 4.7 mEq/L and remained stable, not going above 5.0 mEq/L on subsequent monitoring. The patient had resolution of all symptoms and was discharged.
Discussion
We have described in detail the presentation of each pathology and mechanisms of each treatment, starting with the patient’s initial condition that brought him to the emergency room—muscle weakness. Skeletal muscle weakness is a common manifestation of hyperkalemia, occurring in 20% to 40% of cases, and is more prevalent in severe elevations of potassium. Rarely, the weakness can progress to flaccid paralysis of the patient’s extremities and, in extreme cases, the diaphragm.
Muscle weakness progression occurs in a manner that resembles Guillain-Barré syndrome, starting in the lower extremities and ascending toward the upper extremities.10 This is known as secondary hyperkalemic periodic paralysis. Hyperkalemia lowers the transmembrane gradient in neurons, leading to neuronal depolarization independent of the degree of hyperkalemia. If the degree of hyperkalemia is large enough, this depolarization inactivates voltage-gated sodium channels, making neurons refractory to excitation. Electromyographical studies have shown reduction in the compounded muscle action potential.11 The transient nature of this paralysis is reflected by rapid correction of weakness and paralysis when the electrolyte disorder is corrected.
The patient in this case also presented with bradycardia. The ECG manifestations of hyperkalemia can include atrial asystole, intraventricular conduction disturbances, peaked T waves, and widened QRS complexes. However, some patients with renal insufficiency may not exhibit ECG changes despite significantly elevated serum potassium levels.12
The severity of hyperkalemia is crucial in determining the associated ECG changes, with levels > 6.0 mEq/L presenting with abnormalities.13 ECG findings alone may not always accurately reflect the severity of hyperkalemia, as up to 60% of patients with potassium levels > 6.0 mEq/L may not show ECG changes.14 Additionally, extreme hyperkalemia can lead to inconsistent ECG findings, making it challenging to rely solely on ECG for diagnosis and monitoring.8 The level of potassium that causes these effects varies widely through patient populations.
The main mechanism by which hyperkalemia affects the heart’s conduction system is through voltage differences across the conduction fibers and eventual steady-state inactivation of sodium channels. This combination of mechanisms shortens the action potential duration, allowing more cardiomyocytes to undergo synchronized depolarization. This amalgamation of cardiomyocytes repolarizing can be reflected on ECGs as peaked T waves. As the action potential decreases, there is a period during which cardiomyocytes are prone to tachyarrhythmias and ventricular fibrillation.
A reduced action potential may lead to increased rates of depolarization and thus conduction, which in some scenarios may increase heart rate. As the levels of potassium rise, intracellular accumulation impedes the entry of sodium by decreasing the cation gradient across the cell membrane. This effectively slows the sinus nodes and prolongs the QRS by slowing the overall propagation of action potentials. By this mechanism, conduction delays, blocks, or asystole are manifested. The patient in this case showed conduction delays, peaked T waves, and disappearance of P waves when he first arrived.
Hyperkalemia Treatment
Hyperkalemia develops most commonly due to acute or chronic kidney diseases, as was the case with this patient. The patient’s hyperkalemia was also augmented by the use of nonsteroidal anti-inflammatory drugs (NSAIDs), which can directly affect renal function. A properly functioning kidney is responsible for excretion of up to 90% of ingested potassium, while the remainder is excreted through the gastrointestinal (GI) tract. Definitive treatment of hyperkalemia is mitigated primarily through these 2 organ systems. The treatment also includes transitory mechanisms of potassium reduction. The goal of each method is to preserve the action potential of cardiomyocytes and myocytes. This patient presented with acute symptomatic hyperkalemia and received various medications to acutely, transitorily, and definitively treat it.
Initial therapy included calcium gluconate, which functions to stabilize the myocardial cell membrane. Hyperkalemia decreases the resting membrane action potential of excitable cells and predisposes them to early depolarization and thus dysrhythmias. Calcium decreases the threshold potential across cells and offsets the overall gradient back to near normal levels.15 Calcium can be delivered through calcium gluconate or calcium chloride. Calcium chloride is not preferred because extravasation can cause pain, blistering and tissue ischemia. Central venous access is required, potentially delaying prompt treatment. Calcium acts rapidly after administration—within 1 to 3 minutes—but only lasts 30 to 60 minutes.16 Administration of calcium gluconate can be repeated as often as necessary, but patients must be monitored for adverse effects of calcium such as nausea, abdominal pain, polydipsia, polyuria, muscle weakness, and paresthesia. Care must be taken when patients are taking digoxin, because calcium may potentiate toxicity.17 Although calcium provides immediate benefits it does little to correct the underlying cause; other medications are required to remove potassium from the body.
Two medication classes have been proven to shift potassium intracellularly. The first are β-2 agonists, such as albuterol/levalbuterol, and the second is insulin. Both work through sodium-potassium-ATPase in a direct manner. β-2 agonists stimulate sodium-potassium-ATPase to move more potassium intracellularly, but these effects have been seen only with high doses of albuterol, typically 4× the standard dose of 0.5 mg in nebulized solutions to achieve decreases in potassium of 0.3 to 0.6 mEq/L, although some trials have reported decreases of 0.62 to 0.98 mEq/L.15,18 These potassium-lowering effects of β-2 agonist are modest, but can be seen 20 to 30 minutes after administration and persist up to 1 to 2 hours. β-2 agonists are also readily affected by β blockers, which may reduce or negate the desired effect in hyperkalemia. For these reasons, a β-2 agonist should not be given as monotherapy and should be provided as an adjuvant to more independent therapies such as insulin. Insulin binds to receptors on muscle cells and increases the quantity of sodium-potassium-ATPase and glucose transporters. With this increase in influx pumps, surrounding tissues with higher resting membrane potentials can absorb the potassium load, thereby protecting cardiomyocytes.
Potassium Removal
Three methods are currently available to remove potassium from the body: GI excretion, renal excretion, and direct removal from the bloodstream. Under normal physiologic conditions, the kidneys account for about 90% of the body’s ability to remove potassium. Loop diuretics facilitate the removal of potassium by increasing urine production and have an additional potassium-wasting effect. Although the onset of action of loop diuretics is typically 30 to 60 minutes after oral administration, their effect can last for several hours. In this patient, furosemide was introduced later in the treatment plan to manage recurring hyperkalemia by enhancing renal potassium excretion.
Potassium binders such as patiromer act in the GI tract, effectively reducing serum potassium levels although with a slower onset of action than furosemide, generally taking hours to days to exert its effect. Both medications illustrate a tailored approach to managing potassium levels, adapted to the evolving needs and renal function of the patient. The last method is using hemodialysis—by far the most rapid method to remove potassium, but also the most invasive. The different methods of treating hyperkalemia are summarized in Table 2. This patient required multiple days of hemodialysis to completely correct the electrolyte disorder. Upon discharge, the patient continued oral furosemide 40 mg daily and eventually discontinued hemodialysis due to stable renal function.
Often, after correcting an inciting event, potassium stores in the body eventually stabilize and do not require additional follow-up. Patients prone to hyperkalemia should be thoroughly educated on medications to avoid (NSAIDs, ACEIs/ARBs, trimethoprim), an adequate low potassium diet, and symptoms that may warrant medical attention.19
Conclusions
This case illustrates the importance of recognizing the spectrum of manifestations of hyperkalemia, which ranged from muscle weakness to cardiac dysrhythmias. Management strategies for the patient included stabilization of cardiac membranes, potassium shifting, and potassium removal, each tailored to the patient’s individual clinical findings.
The case further illustrates the critical role of continuous monitoring and dynamic adjustment of therapeutic strategies in response to evolving clinical and laboratory findings. The initial and subsequent ECGs, alongside laboratory tests, were instrumental in guiding the adjustments needed in the treatment regimen, ensuring both the efficacy and safety of the interventions. This proactive approach can mitigate the risk of recurrent hyperkalemia and its complications.
- Youn JH, McDonough AA. Recent advances in understanding integrative control of potassium homeostasis. Annu Rev Physiol. 2009;71:381-401. doi:10.1146/annurev.physiol.010908.163241 2.
- Simon LV, Hashmi MF, Farrell MW. Hyperkalemia. In: StatPearls. StatPearls Publishing; September 4, 2023. Accessed October 22, 2025.
- Mu F, Betts KA, Woolley JM, et al. Prevalence and economic burden of hyperkalemia in the United States Medicare population. Curr Med Res Opin. 2020;36:1333-1341. doi:10.1080/03007995.2020.1775072
- Loutradis C, Tolika P, Skodra A, et al. Prevalence of hyperkalemia in diabetic and non-diabetic patients with chronic kidney disease: a nested case-control study. Am J Nephrol. 2015;42:351-360. doi:10.1159/000442393
- Grodzinsky A, Goyal A, Gosch K, et al. Prevalence and prognosis of hyperkalemia in patients with acute myocardial infarction. Am J Med. 2016;129:858-865. doi:10.1016/j.amjmed.2016.03.008
- Hunter RW, Bailey MA. Hyperkalemia: pathophysiology, risk factors and consequences. Nephrol Dial Transplant. 2019;34(suppl 3):iii2-iii11. doi:10.1093/ndt/gfz206
- Luo J, Brunelli SM, Jensen DE, Yang A. Association between serum potassium and outcomes in patients with reduced kidney function. Clin J Am Soc Nephrol. 2016;11:90-100. doi:10.2215/CJN.01730215
- Montford JR, Linas S. How dangerous is hyperkalemia? J Am Soc Nephrol. 2017;28:3155-3165. doi:10.1681/ASN.2016121344
- Mattu A, Brady WJ, Robinson DA. Electrocardiographic manifestations of hyperkalemia. Am J Emerg Med. 2000;18:721-729. doi:10.1053/ajem.2000.7344
- Kimmons LA, Usery JB. Acute ascending muscle weakness secondary to medication-induced hyperkalemia. Case Rep Med. 2014;2014:789529. doi:10.1155/2014/789529
- Naik KR, Saroja AO, Khanpet MS. Reversible electrophysiological abnormalities in acute secondary hyperkalemic paralysis. Ann Indian Acad Neurol. 2012;15:339-343. doi:10.4103/0972-2327.104354
- Montague BT, Ouellette JR, Buller GK. Retrospective review of the frequency of ECG changes in hyperkalemia. Clin J Am Soc Nephrol. 2008;3:324-330. doi:10.2215/CJN.04611007
- Larivée NL, Michaud JB, More KM, Wilson JA, Tennankore KK. Hyperkalemia: prevalence, predictors and emerging treatments. Cardiol Ther. 2023;12:35-63. doi:10.1007/s40119-022-00289-z
- Shingarev R, Allon M. A physiologic-based approach to the treatment of acute hyperkalemia. Am J Kidney Dis. 2010;56:578-584. doi:10.1053/j.ajkd.2010.03.014
- Parham WA, Mehdirad AA, Biermann KM, Fredman CS. Hyperkalemia revisited. Tex Heart Inst J. 2006;33:40-47.
- Ng KE, Lee CS. Updated treatment options in the management of hyperkalemia. U.S. Pharmacist. February 16, 2017. Accessed October 1, 2025. www.uspharmacist.com/article/updated-treatment-options-in-the-management-of-hyperkalemia
- Quick G, Bastani B. Prolonged asystolic hyperkalemic cardiac arrest with no neurologic sequelae. Ann Emerg Med. 1994;24:305-311. doi:10.1016/s0196-0644(94)70144-x 18.
- Allon M, Dunlay R, Copkney C. Nebulized albuterol for acute hyperkalemia in patients on hemodialysis. Ann Intern Med. 1989;110:426-429. doi:10.7326/0003-4819-110-6-42619.
- Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int. 2024;105(4 suppl):S117-S314. doi:10.1016/j.kint.2023.10.018
Hyperkalemia involves elevated serum potassium levels (> 5.0 mEq/L) and represents an important electrolyte disturbance due to its potentially severe consequences, including cardiac effects that can lead to dysrhythmia and even asystole and death.1,2 In a US Medicare population, the prevalence of hyperkalemia has been estimated at 2.7% and is associated with substantial health care costs.3 The prevalence is even more marked in patients with preexisting conditions such as chronic kidney disease (CKD) and heart failure.4,5
Hyperkalemia can result from multiple factors, including impaired renal function, adrenal disease, adverse drug reactions of angiotensin-converting enzyme inhibitors (ACEIs) and other medications, and heritable mutations.6 Hyperkalemia poses a considerable clinical risk, associated with adverse outcomes such as myocardial infarction and increased mortality in patients with CKD.5,7,8 Electrocardiographic (ECG) changes associated with hyperkalemia play a vital role in guiding clinical decisions and treatment strategies.9 Understanding the pathophysiology, risk factors, and consequences of hyperkalemia, as well as the significance of ECG changes in its management, is essential for health care practitioners.
Case Presentation
An 81-year-old Hispanic man with a history of hypertension, hypothyroidism, gout, and CKD stage 3B presented to the emergency department with progressive weakness resulting in falls and culminating in an inability to ambulate independently. Additional symptoms included nausea, diarrhea, and myalgia. His vital signs were notable for a pulse of 41 beats/min. The physical examination was remarkable for significant weakness of the bilateral upper extremities, inability to bear his own weight, and bilateral lower extremity edema. His initial ECG upon arrival showed bradycardia with wide QRS, absent P waves, and peaked T waves (Figure 1a). These findings differed from his baseline ECG taken 1 year earlier, which showed sinus rhythm with premature atrial complexes and an old right bundle branch block (Figure 1b).
Medication review revealed that the patient was currently prescribed 100 mg allopurinol daily, 2.5 mg amlodipine daily, 10 mg atorvastatin at bedtime, 4 mg doxazosin daily, 112 mcg levothyroxine daily, 100 mg losartan daily, 25 mg metoprolol daily, and 0.4 mg tamsulosin daily. The patient had also been taking over-the-counter indomethacin for knee pain.
Based on the ECG results, he was treated with 0.083%/6 mL nebulized albuterol, 4.65 Mq/250 mL saline solution intravenous (IV) calcium gluconate, 10 units IV insulin with concomitant 50%/25 mL IV dextrose and 8.4 g of oral patiromer suspension. IV furosemide was held due to concern for renal function. The decision to proceed with hemodialysis was made. Repeat laboratory tests were performed, and an ECG obtained after treatment initiation but prior to hemodialysis demonstrated improvement of rate and T wave shortening (Figure 1c). The serum potassium level dropped from 9.8 mEq/L to 7.9 mEq/L (reference range, 3.5-5.0 mEq/L) (Table 1).
In addition to hemodialysis, sodium zirconium 10 g orally 3 times daily was added. Laboratory test results and an ECG was performed after dialysis continued to demonstrate improvement (Figure 1d). The patient’s potassium level decreased to 5.8 mEq/L, with the ECG demonstrating stability of heart rate and further improvement of the PR interval, QRS complex, and T waves.
Despite the established treatment regimen, potassium levels again rose to 6.7 mEq/L, but there were no significant changes in the ECG, and thus no medication changes were made (Figure 1e). Subsequent monitoring demonstrated a further increase in potassium to 7.4 mEq/L, with an ECG demonstrating a return to the baseline of 1 year prior. The patient underwent hemodialysis again and was given oral furosemide 60 mg every 12 hours. The potassium concentration after dialysis decreased to 4.7 mEq/L and remained stable, not going above 5.0 mEq/L on subsequent monitoring. The patient had resolution of all symptoms and was discharged.
Discussion
We have described in detail the presentation of each pathology and mechanisms of each treatment, starting with the patient’s initial condition that brought him to the emergency room—muscle weakness. Skeletal muscle weakness is a common manifestation of hyperkalemia, occurring in 20% to 40% of cases, and is more prevalent in severe elevations of potassium. Rarely, the weakness can progress to flaccid paralysis of the patient’s extremities and, in extreme cases, the diaphragm.
Muscle weakness progression occurs in a manner that resembles Guillain-Barré syndrome, starting in the lower extremities and ascending toward the upper extremities.10 This is known as secondary hyperkalemic periodic paralysis. Hyperkalemia lowers the transmembrane gradient in neurons, leading to neuronal depolarization independent of the degree of hyperkalemia. If the degree of hyperkalemia is large enough, this depolarization inactivates voltage-gated sodium channels, making neurons refractory to excitation. Electromyographical studies have shown reduction in the compounded muscle action potential.11 The transient nature of this paralysis is reflected by rapid correction of weakness and paralysis when the electrolyte disorder is corrected.
The patient in this case also presented with bradycardia. The ECG manifestations of hyperkalemia can include atrial asystole, intraventricular conduction disturbances, peaked T waves, and widened QRS complexes. However, some patients with renal insufficiency may not exhibit ECG changes despite significantly elevated serum potassium levels.12
The severity of hyperkalemia is crucial in determining the associated ECG changes, with levels > 6.0 mEq/L presenting with abnormalities.13 ECG findings alone may not always accurately reflect the severity of hyperkalemia, as up to 60% of patients with potassium levels > 6.0 mEq/L may not show ECG changes.14 Additionally, extreme hyperkalemia can lead to inconsistent ECG findings, making it challenging to rely solely on ECG for diagnosis and monitoring.8 The level of potassium that causes these effects varies widely through patient populations.
The main mechanism by which hyperkalemia affects the heart’s conduction system is through voltage differences across the conduction fibers and eventual steady-state inactivation of sodium channels. This combination of mechanisms shortens the action potential duration, allowing more cardiomyocytes to undergo synchronized depolarization. This amalgamation of cardiomyocytes repolarizing can be reflected on ECGs as peaked T waves. As the action potential decreases, there is a period during which cardiomyocytes are prone to tachyarrhythmias and ventricular fibrillation.
A reduced action potential may lead to increased rates of depolarization and thus conduction, which in some scenarios may increase heart rate. As the levels of potassium rise, intracellular accumulation impedes the entry of sodium by decreasing the cation gradient across the cell membrane. This effectively slows the sinus nodes and prolongs the QRS by slowing the overall propagation of action potentials. By this mechanism, conduction delays, blocks, or asystole are manifested. The patient in this case showed conduction delays, peaked T waves, and disappearance of P waves when he first arrived.
Hyperkalemia Treatment
Hyperkalemia develops most commonly due to acute or chronic kidney diseases, as was the case with this patient. The patient’s hyperkalemia was also augmented by the use of nonsteroidal anti-inflammatory drugs (NSAIDs), which can directly affect renal function. A properly functioning kidney is responsible for excretion of up to 90% of ingested potassium, while the remainder is excreted through the gastrointestinal (GI) tract. Definitive treatment of hyperkalemia is mitigated primarily through these 2 organ systems. The treatment also includes transitory mechanisms of potassium reduction. The goal of each method is to preserve the action potential of cardiomyocytes and myocytes. This patient presented with acute symptomatic hyperkalemia and received various medications to acutely, transitorily, and definitively treat it.
Initial therapy included calcium gluconate, which functions to stabilize the myocardial cell membrane. Hyperkalemia decreases the resting membrane action potential of excitable cells and predisposes them to early depolarization and thus dysrhythmias. Calcium decreases the threshold potential across cells and offsets the overall gradient back to near normal levels.15 Calcium can be delivered through calcium gluconate or calcium chloride. Calcium chloride is not preferred because extravasation can cause pain, blistering and tissue ischemia. Central venous access is required, potentially delaying prompt treatment. Calcium acts rapidly after administration—within 1 to 3 minutes—but only lasts 30 to 60 minutes.16 Administration of calcium gluconate can be repeated as often as necessary, but patients must be monitored for adverse effects of calcium such as nausea, abdominal pain, polydipsia, polyuria, muscle weakness, and paresthesia. Care must be taken when patients are taking digoxin, because calcium may potentiate toxicity.17 Although calcium provides immediate benefits it does little to correct the underlying cause; other medications are required to remove potassium from the body.
Two medication classes have been proven to shift potassium intracellularly. The first are β-2 agonists, such as albuterol/levalbuterol, and the second is insulin. Both work through sodium-potassium-ATPase in a direct manner. β-2 agonists stimulate sodium-potassium-ATPase to move more potassium intracellularly, but these effects have been seen only with high doses of albuterol, typically 4× the standard dose of 0.5 mg in nebulized solutions to achieve decreases in potassium of 0.3 to 0.6 mEq/L, although some trials have reported decreases of 0.62 to 0.98 mEq/L.15,18 These potassium-lowering effects of β-2 agonist are modest, but can be seen 20 to 30 minutes after administration and persist up to 1 to 2 hours. β-2 agonists are also readily affected by β blockers, which may reduce or negate the desired effect in hyperkalemia. For these reasons, a β-2 agonist should not be given as monotherapy and should be provided as an adjuvant to more independent therapies such as insulin. Insulin binds to receptors on muscle cells and increases the quantity of sodium-potassium-ATPase and glucose transporters. With this increase in influx pumps, surrounding tissues with higher resting membrane potentials can absorb the potassium load, thereby protecting cardiomyocytes.
Potassium Removal
Three methods are currently available to remove potassium from the body: GI excretion, renal excretion, and direct removal from the bloodstream. Under normal physiologic conditions, the kidneys account for about 90% of the body’s ability to remove potassium. Loop diuretics facilitate the removal of potassium by increasing urine production and have an additional potassium-wasting effect. Although the onset of action of loop diuretics is typically 30 to 60 minutes after oral administration, their effect can last for several hours. In this patient, furosemide was introduced later in the treatment plan to manage recurring hyperkalemia by enhancing renal potassium excretion.
Potassium binders such as patiromer act in the GI tract, effectively reducing serum potassium levels although with a slower onset of action than furosemide, generally taking hours to days to exert its effect. Both medications illustrate a tailored approach to managing potassium levels, adapted to the evolving needs and renal function of the patient. The last method is using hemodialysis—by far the most rapid method to remove potassium, but also the most invasive. The different methods of treating hyperkalemia are summarized in Table 2. This patient required multiple days of hemodialysis to completely correct the electrolyte disorder. Upon discharge, the patient continued oral furosemide 40 mg daily and eventually discontinued hemodialysis due to stable renal function.
Often, after correcting an inciting event, potassium stores in the body eventually stabilize and do not require additional follow-up. Patients prone to hyperkalemia should be thoroughly educated on medications to avoid (NSAIDs, ACEIs/ARBs, trimethoprim), an adequate low potassium diet, and symptoms that may warrant medical attention.19
Conclusions
This case illustrates the importance of recognizing the spectrum of manifestations of hyperkalemia, which ranged from muscle weakness to cardiac dysrhythmias. Management strategies for the patient included stabilization of cardiac membranes, potassium shifting, and potassium removal, each tailored to the patient’s individual clinical findings.
The case further illustrates the critical role of continuous monitoring and dynamic adjustment of therapeutic strategies in response to evolving clinical and laboratory findings. The initial and subsequent ECGs, alongside laboratory tests, were instrumental in guiding the adjustments needed in the treatment regimen, ensuring both the efficacy and safety of the interventions. This proactive approach can mitigate the risk of recurrent hyperkalemia and its complications.
Hyperkalemia involves elevated serum potassium levels (> 5.0 mEq/L) and represents an important electrolyte disturbance due to its potentially severe consequences, including cardiac effects that can lead to dysrhythmia and even asystole and death.1,2 In a US Medicare population, the prevalence of hyperkalemia has been estimated at 2.7% and is associated with substantial health care costs.3 The prevalence is even more marked in patients with preexisting conditions such as chronic kidney disease (CKD) and heart failure.4,5
Hyperkalemia can result from multiple factors, including impaired renal function, adrenal disease, adverse drug reactions of angiotensin-converting enzyme inhibitors (ACEIs) and other medications, and heritable mutations.6 Hyperkalemia poses a considerable clinical risk, associated with adverse outcomes such as myocardial infarction and increased mortality in patients with CKD.5,7,8 Electrocardiographic (ECG) changes associated with hyperkalemia play a vital role in guiding clinical decisions and treatment strategies.9 Understanding the pathophysiology, risk factors, and consequences of hyperkalemia, as well as the significance of ECG changes in its management, is essential for health care practitioners.
Case Presentation
An 81-year-old Hispanic man with a history of hypertension, hypothyroidism, gout, and CKD stage 3B presented to the emergency department with progressive weakness resulting in falls and culminating in an inability to ambulate independently. Additional symptoms included nausea, diarrhea, and myalgia. His vital signs were notable for a pulse of 41 beats/min. The physical examination was remarkable for significant weakness of the bilateral upper extremities, inability to bear his own weight, and bilateral lower extremity edema. His initial ECG upon arrival showed bradycardia with wide QRS, absent P waves, and peaked T waves (Figure 1a). These findings differed from his baseline ECG taken 1 year earlier, which showed sinus rhythm with premature atrial complexes and an old right bundle branch block (Figure 1b).
Medication review revealed that the patient was currently prescribed 100 mg allopurinol daily, 2.5 mg amlodipine daily, 10 mg atorvastatin at bedtime, 4 mg doxazosin daily, 112 mcg levothyroxine daily, 100 mg losartan daily, 25 mg metoprolol daily, and 0.4 mg tamsulosin daily. The patient had also been taking over-the-counter indomethacin for knee pain.
Based on the ECG results, he was treated with 0.083%/6 mL nebulized albuterol, 4.65 Mq/250 mL saline solution intravenous (IV) calcium gluconate, 10 units IV insulin with concomitant 50%/25 mL IV dextrose and 8.4 g of oral patiromer suspension. IV furosemide was held due to concern for renal function. The decision to proceed with hemodialysis was made. Repeat laboratory tests were performed, and an ECG obtained after treatment initiation but prior to hemodialysis demonstrated improvement of rate and T wave shortening (Figure 1c). The serum potassium level dropped from 9.8 mEq/L to 7.9 mEq/L (reference range, 3.5-5.0 mEq/L) (Table 1).
In addition to hemodialysis, sodium zirconium 10 g orally 3 times daily was added. Laboratory test results and an ECG was performed after dialysis continued to demonstrate improvement (Figure 1d). The patient’s potassium level decreased to 5.8 mEq/L, with the ECG demonstrating stability of heart rate and further improvement of the PR interval, QRS complex, and T waves.
Despite the established treatment regimen, potassium levels again rose to 6.7 mEq/L, but there were no significant changes in the ECG, and thus no medication changes were made (Figure 1e). Subsequent monitoring demonstrated a further increase in potassium to 7.4 mEq/L, with an ECG demonstrating a return to the baseline of 1 year prior. The patient underwent hemodialysis again and was given oral furosemide 60 mg every 12 hours. The potassium concentration after dialysis decreased to 4.7 mEq/L and remained stable, not going above 5.0 mEq/L on subsequent monitoring. The patient had resolution of all symptoms and was discharged.
Discussion
We have described in detail the presentation of each pathology and mechanisms of each treatment, starting with the patient’s initial condition that brought him to the emergency room—muscle weakness. Skeletal muscle weakness is a common manifestation of hyperkalemia, occurring in 20% to 40% of cases, and is more prevalent in severe elevations of potassium. Rarely, the weakness can progress to flaccid paralysis of the patient’s extremities and, in extreme cases, the diaphragm.
Muscle weakness progression occurs in a manner that resembles Guillain-Barré syndrome, starting in the lower extremities and ascending toward the upper extremities.10 This is known as secondary hyperkalemic periodic paralysis. Hyperkalemia lowers the transmembrane gradient in neurons, leading to neuronal depolarization independent of the degree of hyperkalemia. If the degree of hyperkalemia is large enough, this depolarization inactivates voltage-gated sodium channels, making neurons refractory to excitation. Electromyographical studies have shown reduction in the compounded muscle action potential.11 The transient nature of this paralysis is reflected by rapid correction of weakness and paralysis when the electrolyte disorder is corrected.
The patient in this case also presented with bradycardia. The ECG manifestations of hyperkalemia can include atrial asystole, intraventricular conduction disturbances, peaked T waves, and widened QRS complexes. However, some patients with renal insufficiency may not exhibit ECG changes despite significantly elevated serum potassium levels.12
The severity of hyperkalemia is crucial in determining the associated ECG changes, with levels > 6.0 mEq/L presenting with abnormalities.13 ECG findings alone may not always accurately reflect the severity of hyperkalemia, as up to 60% of patients with potassium levels > 6.0 mEq/L may not show ECG changes.14 Additionally, extreme hyperkalemia can lead to inconsistent ECG findings, making it challenging to rely solely on ECG for diagnosis and monitoring.8 The level of potassium that causes these effects varies widely through patient populations.
The main mechanism by which hyperkalemia affects the heart’s conduction system is through voltage differences across the conduction fibers and eventual steady-state inactivation of sodium channels. This combination of mechanisms shortens the action potential duration, allowing more cardiomyocytes to undergo synchronized depolarization. This amalgamation of cardiomyocytes repolarizing can be reflected on ECGs as peaked T waves. As the action potential decreases, there is a period during which cardiomyocytes are prone to tachyarrhythmias and ventricular fibrillation.
A reduced action potential may lead to increased rates of depolarization and thus conduction, which in some scenarios may increase heart rate. As the levels of potassium rise, intracellular accumulation impedes the entry of sodium by decreasing the cation gradient across the cell membrane. This effectively slows the sinus nodes and prolongs the QRS by slowing the overall propagation of action potentials. By this mechanism, conduction delays, blocks, or asystole are manifested. The patient in this case showed conduction delays, peaked T waves, and disappearance of P waves when he first arrived.
Hyperkalemia Treatment
Hyperkalemia develops most commonly due to acute or chronic kidney diseases, as was the case with this patient. The patient’s hyperkalemia was also augmented by the use of nonsteroidal anti-inflammatory drugs (NSAIDs), which can directly affect renal function. A properly functioning kidney is responsible for excretion of up to 90% of ingested potassium, while the remainder is excreted through the gastrointestinal (GI) tract. Definitive treatment of hyperkalemia is mitigated primarily through these 2 organ systems. The treatment also includes transitory mechanisms of potassium reduction. The goal of each method is to preserve the action potential of cardiomyocytes and myocytes. This patient presented with acute symptomatic hyperkalemia and received various medications to acutely, transitorily, and definitively treat it.
Initial therapy included calcium gluconate, which functions to stabilize the myocardial cell membrane. Hyperkalemia decreases the resting membrane action potential of excitable cells and predisposes them to early depolarization and thus dysrhythmias. Calcium decreases the threshold potential across cells and offsets the overall gradient back to near normal levels.15 Calcium can be delivered through calcium gluconate or calcium chloride. Calcium chloride is not preferred because extravasation can cause pain, blistering and tissue ischemia. Central venous access is required, potentially delaying prompt treatment. Calcium acts rapidly after administration—within 1 to 3 minutes—but only lasts 30 to 60 minutes.16 Administration of calcium gluconate can be repeated as often as necessary, but patients must be monitored for adverse effects of calcium such as nausea, abdominal pain, polydipsia, polyuria, muscle weakness, and paresthesia. Care must be taken when patients are taking digoxin, because calcium may potentiate toxicity.17 Although calcium provides immediate benefits it does little to correct the underlying cause; other medications are required to remove potassium from the body.
Two medication classes have been proven to shift potassium intracellularly. The first are β-2 agonists, such as albuterol/levalbuterol, and the second is insulin. Both work through sodium-potassium-ATPase in a direct manner. β-2 agonists stimulate sodium-potassium-ATPase to move more potassium intracellularly, but these effects have been seen only with high doses of albuterol, typically 4× the standard dose of 0.5 mg in nebulized solutions to achieve decreases in potassium of 0.3 to 0.6 mEq/L, although some trials have reported decreases of 0.62 to 0.98 mEq/L.15,18 These potassium-lowering effects of β-2 agonist are modest, but can be seen 20 to 30 minutes after administration and persist up to 1 to 2 hours. β-2 agonists are also readily affected by β blockers, which may reduce or negate the desired effect in hyperkalemia. For these reasons, a β-2 agonist should not be given as monotherapy and should be provided as an adjuvant to more independent therapies such as insulin. Insulin binds to receptors on muscle cells and increases the quantity of sodium-potassium-ATPase and glucose transporters. With this increase in influx pumps, surrounding tissues with higher resting membrane potentials can absorb the potassium load, thereby protecting cardiomyocytes.
Potassium Removal
Three methods are currently available to remove potassium from the body: GI excretion, renal excretion, and direct removal from the bloodstream. Under normal physiologic conditions, the kidneys account for about 90% of the body’s ability to remove potassium. Loop diuretics facilitate the removal of potassium by increasing urine production and have an additional potassium-wasting effect. Although the onset of action of loop diuretics is typically 30 to 60 minutes after oral administration, their effect can last for several hours. In this patient, furosemide was introduced later in the treatment plan to manage recurring hyperkalemia by enhancing renal potassium excretion.
Potassium binders such as patiromer act in the GI tract, effectively reducing serum potassium levels although with a slower onset of action than furosemide, generally taking hours to days to exert its effect. Both medications illustrate a tailored approach to managing potassium levels, adapted to the evolving needs and renal function of the patient. The last method is using hemodialysis—by far the most rapid method to remove potassium, but also the most invasive. The different methods of treating hyperkalemia are summarized in Table 2. This patient required multiple days of hemodialysis to completely correct the electrolyte disorder. Upon discharge, the patient continued oral furosemide 40 mg daily and eventually discontinued hemodialysis due to stable renal function.
Often, after correcting an inciting event, potassium stores in the body eventually stabilize and do not require additional follow-up. Patients prone to hyperkalemia should be thoroughly educated on medications to avoid (NSAIDs, ACEIs/ARBs, trimethoprim), an adequate low potassium diet, and symptoms that may warrant medical attention.19
Conclusions
This case illustrates the importance of recognizing the spectrum of manifestations of hyperkalemia, which ranged from muscle weakness to cardiac dysrhythmias. Management strategies for the patient included stabilization of cardiac membranes, potassium shifting, and potassium removal, each tailored to the patient’s individual clinical findings.
The case further illustrates the critical role of continuous monitoring and dynamic adjustment of therapeutic strategies in response to evolving clinical and laboratory findings. The initial and subsequent ECGs, alongside laboratory tests, were instrumental in guiding the adjustments needed in the treatment regimen, ensuring both the efficacy and safety of the interventions. This proactive approach can mitigate the risk of recurrent hyperkalemia and its complications.
- Youn JH, McDonough AA. Recent advances in understanding integrative control of potassium homeostasis. Annu Rev Physiol. 2009;71:381-401. doi:10.1146/annurev.physiol.010908.163241 2.
- Simon LV, Hashmi MF, Farrell MW. Hyperkalemia. In: StatPearls. StatPearls Publishing; September 4, 2023. Accessed October 22, 2025.
- Mu F, Betts KA, Woolley JM, et al. Prevalence and economic burden of hyperkalemia in the United States Medicare population. Curr Med Res Opin. 2020;36:1333-1341. doi:10.1080/03007995.2020.1775072
- Loutradis C, Tolika P, Skodra A, et al. Prevalence of hyperkalemia in diabetic and non-diabetic patients with chronic kidney disease: a nested case-control study. Am J Nephrol. 2015;42:351-360. doi:10.1159/000442393
- Grodzinsky A, Goyal A, Gosch K, et al. Prevalence and prognosis of hyperkalemia in patients with acute myocardial infarction. Am J Med. 2016;129:858-865. doi:10.1016/j.amjmed.2016.03.008
- Hunter RW, Bailey MA. Hyperkalemia: pathophysiology, risk factors and consequences. Nephrol Dial Transplant. 2019;34(suppl 3):iii2-iii11. doi:10.1093/ndt/gfz206
- Luo J, Brunelli SM, Jensen DE, Yang A. Association between serum potassium and outcomes in patients with reduced kidney function. Clin J Am Soc Nephrol. 2016;11:90-100. doi:10.2215/CJN.01730215
- Montford JR, Linas S. How dangerous is hyperkalemia? J Am Soc Nephrol. 2017;28:3155-3165. doi:10.1681/ASN.2016121344
- Mattu A, Brady WJ, Robinson DA. Electrocardiographic manifestations of hyperkalemia. Am J Emerg Med. 2000;18:721-729. doi:10.1053/ajem.2000.7344
- Kimmons LA, Usery JB. Acute ascending muscle weakness secondary to medication-induced hyperkalemia. Case Rep Med. 2014;2014:789529. doi:10.1155/2014/789529
- Naik KR, Saroja AO, Khanpet MS. Reversible electrophysiological abnormalities in acute secondary hyperkalemic paralysis. Ann Indian Acad Neurol. 2012;15:339-343. doi:10.4103/0972-2327.104354
- Montague BT, Ouellette JR, Buller GK. Retrospective review of the frequency of ECG changes in hyperkalemia. Clin J Am Soc Nephrol. 2008;3:324-330. doi:10.2215/CJN.04611007
- Larivée NL, Michaud JB, More KM, Wilson JA, Tennankore KK. Hyperkalemia: prevalence, predictors and emerging treatments. Cardiol Ther. 2023;12:35-63. doi:10.1007/s40119-022-00289-z
- Shingarev R, Allon M. A physiologic-based approach to the treatment of acute hyperkalemia. Am J Kidney Dis. 2010;56:578-584. doi:10.1053/j.ajkd.2010.03.014
- Parham WA, Mehdirad AA, Biermann KM, Fredman CS. Hyperkalemia revisited. Tex Heart Inst J. 2006;33:40-47.
- Ng KE, Lee CS. Updated treatment options in the management of hyperkalemia. U.S. Pharmacist. February 16, 2017. Accessed October 1, 2025. www.uspharmacist.com/article/updated-treatment-options-in-the-management-of-hyperkalemia
- Quick G, Bastani B. Prolonged asystolic hyperkalemic cardiac arrest with no neurologic sequelae. Ann Emerg Med. 1994;24:305-311. doi:10.1016/s0196-0644(94)70144-x 18.
- Allon M, Dunlay R, Copkney C. Nebulized albuterol for acute hyperkalemia in patients on hemodialysis. Ann Intern Med. 1989;110:426-429. doi:10.7326/0003-4819-110-6-42619.
- Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int. 2024;105(4 suppl):S117-S314. doi:10.1016/j.kint.2023.10.018
- Youn JH, McDonough AA. Recent advances in understanding integrative control of potassium homeostasis. Annu Rev Physiol. 2009;71:381-401. doi:10.1146/annurev.physiol.010908.163241 2.
- Simon LV, Hashmi MF, Farrell MW. Hyperkalemia. In: StatPearls. StatPearls Publishing; September 4, 2023. Accessed October 22, 2025.
- Mu F, Betts KA, Woolley JM, et al. Prevalence and economic burden of hyperkalemia in the United States Medicare population. Curr Med Res Opin. 2020;36:1333-1341. doi:10.1080/03007995.2020.1775072
- Loutradis C, Tolika P, Skodra A, et al. Prevalence of hyperkalemia in diabetic and non-diabetic patients with chronic kidney disease: a nested case-control study. Am J Nephrol. 2015;42:351-360. doi:10.1159/000442393
- Grodzinsky A, Goyal A, Gosch K, et al. Prevalence and prognosis of hyperkalemia in patients with acute myocardial infarction. Am J Med. 2016;129:858-865. doi:10.1016/j.amjmed.2016.03.008
- Hunter RW, Bailey MA. Hyperkalemia: pathophysiology, risk factors and consequences. Nephrol Dial Transplant. 2019;34(suppl 3):iii2-iii11. doi:10.1093/ndt/gfz206
- Luo J, Brunelli SM, Jensen DE, Yang A. Association between serum potassium and outcomes in patients with reduced kidney function. Clin J Am Soc Nephrol. 2016;11:90-100. doi:10.2215/CJN.01730215
- Montford JR, Linas S. How dangerous is hyperkalemia? J Am Soc Nephrol. 2017;28:3155-3165. doi:10.1681/ASN.2016121344
- Mattu A, Brady WJ, Robinson DA. Electrocardiographic manifestations of hyperkalemia. Am J Emerg Med. 2000;18:721-729. doi:10.1053/ajem.2000.7344
- Kimmons LA, Usery JB. Acute ascending muscle weakness secondary to medication-induced hyperkalemia. Case Rep Med. 2014;2014:789529. doi:10.1155/2014/789529
- Naik KR, Saroja AO, Khanpet MS. Reversible electrophysiological abnormalities in acute secondary hyperkalemic paralysis. Ann Indian Acad Neurol. 2012;15:339-343. doi:10.4103/0972-2327.104354
- Montague BT, Ouellette JR, Buller GK. Retrospective review of the frequency of ECG changes in hyperkalemia. Clin J Am Soc Nephrol. 2008;3:324-330. doi:10.2215/CJN.04611007
- Larivée NL, Michaud JB, More KM, Wilson JA, Tennankore KK. Hyperkalemia: prevalence, predictors and emerging treatments. Cardiol Ther. 2023;12:35-63. doi:10.1007/s40119-022-00289-z
- Shingarev R, Allon M. A physiologic-based approach to the treatment of acute hyperkalemia. Am J Kidney Dis. 2010;56:578-584. doi:10.1053/j.ajkd.2010.03.014
- Parham WA, Mehdirad AA, Biermann KM, Fredman CS. Hyperkalemia revisited. Tex Heart Inst J. 2006;33:40-47.
- Ng KE, Lee CS. Updated treatment options in the management of hyperkalemia. U.S. Pharmacist. February 16, 2017. Accessed October 1, 2025. www.uspharmacist.com/article/updated-treatment-options-in-the-management-of-hyperkalemia
- Quick G, Bastani B. Prolonged asystolic hyperkalemic cardiac arrest with no neurologic sequelae. Ann Emerg Med. 1994;24:305-311. doi:10.1016/s0196-0644(94)70144-x 18.
- Allon M, Dunlay R, Copkney C. Nebulized albuterol for acute hyperkalemia in patients on hemodialysis. Ann Intern Med. 1989;110:426-429. doi:10.7326/0003-4819-110-6-42619.
- Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int. 2024;105(4 suppl):S117-S314. doi:10.1016/j.kint.2023.10.018
Following the Hyperkalemia Trail: A Case Report of ECG Changes and Treatment Responses
Following the Hyperkalemia Trail: A Case Report of ECG Changes and Treatment Responses
