What is the most concerning electrolyte abnormality in a patient with End-Stage Renal Disease (ESRD) who misses a dialysis session?

Hyperkalemia in Missed Dialysis Sessions

Hyperkalemia is the most concerning electrolyte abnormality when an ESRD patient misses dialysis, as it represents a potentially life-threatening emergency that can cause fatal cardiac arrhythmias. 1, 2

Why Hyperkalemia is the Primary Concern

• Hyperkalemia occurs in up to 65% of hospitalized patients with chronic kidney disease and is the leading cause of electrolyte-related mortality in ESRD patients 2
• The prevalence of hyperkalemia in maintenance hemodialysis patients ranges from 8.7-10%, with mortality related to hyperkalemia estimated at 3.1 per 1,000 patient-years 3
• Approximately 24% of hemodialysis patients require emergency dialysis specifically due to severe hyperkalemia 3
• Cardiovascular causes account for at least 40% of deaths in ESRD patients, with 20% being sudden cardiac death, often triggered by electrolyte disturbances, particularly potassium 1

Mechanism of Hyperkalemia in Missed Dialysis

• In ESRD, approximately 90% of potassium excretion normally depends on renal function, with only 10% through colonic excretion 3
• When dialysis is missed, patients lose their primary mechanism for potassium removal, leading to rapid accumulation from dietary intake and cellular breakdown 4, 5
• Extrarenal disposal mechanisms (gastrointestinal excretion and cellular uptake) are insufficient to prevent dangerous potassium accumulation in ESRD patients 5

Cardiac Risk Assessment

• The acute management of ventricular arrhythmias in end-stage renal failure must immediately address hemodynamic status and electrolyte imbalance, particularly potassium, magnesium, and calcium 1
• Severe hyperkalemia (>6.0 mmol/L) requires continuous cardiac monitoring and urgent treatment 2
• In documented cases of hyperkalemia-induced cardiac arrest, AKI or ESRD was present in all patients 2
• QRS duration of 120 ms or greater is most predictive of hyperkalemia in the ESRD population, though ECG changes correlate poorly with absolute potassium levels 6

Other Electrolyte Concerns (Secondary Priority)

While hyperkalemia is the primary concern, other electrolyte abnormalities can accumulate:

• Hyperphosphatemia develops due to reduced renal excretion, leading to secondary hypocalcemia and alterations in vitamin D metabolism 2
• Metabolic acidosis worsens as the kidneys cannot excrete hydrogen ions 7
• Hypermagnesemia can occur but is generally less immediately life-threatening than hyperkalemia 7

Common Pitfalls to Avoid

• Do not wait for ECG changes to treat suspected hyperkalemia in a patient who missed dialysis—ECG findings have poor correlation with serum potassium levels in ESRD patients 6
• Avoid assuming the patient is stable based on lack of symptoms, as hyperkalemia can be "silent" until it causes fatal arrhythmias 3
• Check electrolytes immediately when an ESRD patient presents after missing dialysis, rather than waiting for symptoms to develop 1, 2
• Monitor for at least 4-5 hours after any intervention, as arrhythmias can occur during this period even after initial treatment 1

Immediate Management Priorities

• Obtain stat serum potassium, place patient on continuous cardiac monitoring, and obtain 12-lead ECG immediately 1, 2
• If potassium is >6.5 mmol/L or any ECG changes are present, initiate emergency treatment with calcium (for cardiac membrane stabilization), insulin/glucose (for cellular shift), and arrange emergent dialysis 2
• Arrange emergent hemodialysis as the definitive treatment, as this is the only method that actually removes potassium from the body in ESRD patients 4, 8