Can temporary hyperkalemia due to rhabdomyolysis occur after intense exercise with self-resolved peaked T waves on electrocardiogram (ECG)?

Temporary Hyperkalemia with Self-Resolved Peaked T Waves Following Intense Exercise

Yes, temporary hyperkalemia with self-resolving peaked T waves can absolutely occur after intense exercise, particularly in the context of exertional rhabdomyolysis, and represents a recognized clinical phenomenon that typically resolves with rest and hydration.

Pathophysiology of Exercise-Induced Hyperkalemia

The mechanism involves a cascade of metabolic derangements triggered by intense muscular activity:

• Muscle cell breakdown releases intracellular potassium into the circulation, with rhabdomyolysis causing leakage of myoglobin, intracellular proteins, and electrolytes into the bloodstream 1, 2
• The sequence begins with muscle injury from intense exercise, progressing to rhabdomyolysis, which then leads to hyperkalemia, lactic acidosis, and potential cardiac complications 3
• Exertional rhabdomyolysis can promote disseminated intravascular coagulation, which in turn leads to hyperkalemia, worsening hypoxia, impaired cardiac function, and potentially lethal arrhythmias 3

ECG Manifestations and Their Significance

Peaked T waves represent the earliest and most sensitive ECG marker of hyperkalemia:

• Peaked/tented T waves typically appear at serum potassium levels >5.5 mmol/L and are the first ECG finding in hyperkalemia 4
• The progressive sequence of ECG changes begins with peaked T waves → flattened P waves → prolonged PR interval → widened QRS → sine wave pattern → asystole 4, 5
• Self-resolution of peaked T waves indicates that potassium levels have normalized as the muscle injury stabilizes and renal excretion clears the excess potassium 4

Clinical Context: When This Occurs

This phenomenon is most likely under specific circumstances:

• Events typically occur early in training season or after deconditioning, often in ambient temperatures ≥80°F, at high altitude, or associated with rhabdomyolysis development 3
• Exercise-induced rhabdomyolysis often affects both untrained individuals who abruptly initiate strenuous exercise AND well-trained individuals during particularly intense sessions 6
• The metabolic insult includes lactic acidosis, hyperkalemia, and hypocalcemia, which can lead to cardiac complications if severe 3

Important Clinical Distinctions

Several key points differentiate this benign, self-limited process from dangerous hyperkalemia:

• Rhabdomyolysis-induced hyperkalemia can be life-threatening if severe, particularly when associated with acute kidney injury, which occurs in 13-50% of rhabdomyolysis cases 1, 7
• The absence of ECG changes does not rule out dangerous hyperkalemia, and patients with chronic conditions may tolerate higher potassium levels without ECG manifestations 4, 8
• Self-resolution suggests mild-to-moderate hyperkalemia without renal impairment, as the kidneys successfully excrete the potassium load once muscle breakdown ceases 2

Critical Pitfalls and Red Flags

When evaluating a patient with this presentation, watch for:

• Persistent or worsening symptoms (muscle weakness, cramping, pain, fatigue, excessive dyspnea) require immediate cessation of activity and medical evaluation 3
• Failure to recognize that hyperkalemia can recur if the patient returns to intense exercise without adequate conditioning, hydration, and gradual progression 3
• Underlying conditions that increase risk: sickle cell trait, chronic kidney disease, diabetes, heart failure, or medications affecting potassium homeostasis (RAAS inhibitors, NSAIDs, potassium-sparing diuretics) 3, 4, 8
• Acute kidney injury development transforms a benign, self-limited process into a life-threatening emergency requiring aggressive intervention 1, 7

Management Approach for Self-Resolved Cases

For patients who present after symptom resolution:

• Confirm resolution with repeat ECG and serum potassium measurement to document normalization 4, 8
• Assess for rhabdomyolysis markers: check creatine kinase (CK), myoglobin, and renal function to determine extent of muscle injury 2, 6
• Implement preventive strategies: gradual conditioning, adequate hydration, modified pace during training, and immediate cessation of activity if warning symptoms develop 3
• Screen for underlying risk factors: consider sickle cell trait testing in appropriate populations, review medications, and assess renal function 3, 8

When Immediate Intervention Is Required

If the patient had NOT self-resolved or presents acutely:

• Any ECG changes beyond peaked T waves (flattened P waves, prolonged PR, widened QRS) require immediate calcium administration for membrane stabilization 4, 8
• Severe hyperkalemia (>6.0 mEq/L) with ECG changes mandates hospital admission with continuous cardiac monitoring 4, 8
• Treatment algorithm: calcium gluconate/chloride for membrane stabilization → insulin/glucose for intracellular shift → albuterol nebulization → sodium bicarbonate → diuretics or dialysis for elimination 4, 8