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BASICS

Description

  • Hyperkalemia: plasma potassium (K) >5.5 mEq/L (>5 mmol/L).
  • Can depress cardiac conduction → fatal arrhythmias.
  • Potassium homeostasis regulated by insulin, renin-angiotensin-aldosterone system (RAAS), and renal excretion.

Epidemiology

  • Incidence higher in older adults, males, CKD patients, and those on RAAS inhibitors.
  • Prevalence: 1-10% hospitalized; 2-3% general population; up to 50% in CKD.

ETIOLOGY AND PATHOPHYSIOLOGY

Causes

  • Pseudohyperkalemia: hemolysis during blood draw, thrombocytosis, leukocytosis.
  • Increased potassium load: dietary excess, salt substitutes, tissue breakdown (rhabdomyolysis, tumor lysis).
  • Cellular redistribution: acidosis, insulin deficiency, hyperglycemia, trauma.
  • Decreased excretion: renal failure, hypoaldosteronism, Addison disease, medications.

Risk Factors

  • Impaired renal K excretion.
  • Acidemia.
  • Massive cell lysis (burns, trauma).
  • Use of K-sparing diuretics, K supplements.
  • Comorbidities: CKD, diabetes, heart failure, liver disease.

DIAGNOSIS

History

  • Muscle cramps, weakness, paralysis.
  • Abdominal pain.
  • Palpitations, arrhythmias.

Physical Exam

  • Decreased deep tendon reflexes.
  • Muscle weakness or flaccid paralysis.

Tests

  • Serum electrolytes, BUN, creatinine.
  • Urinalysis for potassium handling.
  • Cortisol, aldosterone, renin if mineralocorticoid deficiency suspected.
  • ECG changes at K ≥7 mEq/L: peaked T waves, prolonged PR, loss of P waves, widened QRS, sine wave pattern.

TREATMENT

Emergency Management

Stabilize myocardium

  • Calcium gluconate 1 g IV over 2-3 minutes; repeat if needed.
  • Cardiac monitoring essential.

Shift K into cells

  • Insulin 10 U IV with 50 mL 50% dextrose if glucose <250 mg/dL.
  • Nebulized albuterol 10-20 mg over >10 min.
  • Sodium bicarbonate (if severe acidosis; not routine).

Remove potassium

  • Cation exchange resins:
  • Patiromer calcium (Veltassa) 8.4 g PO daily; onset 7–24 h.
  • Sodium zirconium cyclosilicate (Lokelma) 10 g PO TID up to 48 h.
  • Sodium polystyrene sulfonate (Kayexalate) 15 g PO or 30 g rectally; onset 1-4 h.
  • Loop diuretics (furosemide 40 mg IV q12h) with isotonic fluids if euvolemic/hypovolemic.
  • Hemodialysis for refractory or severe cases.

Chronic Management

  • Review and discontinue causative meds.
  • Low potassium diet counseling.
  • Diuretics for potassium control.

ALERTS

  • Kayexalate may cause sodium overload; contraindicated in bowel obstruction or postoperative patients due to risk of intestinal necrosis.
  • IV calcium contraindicated or used cautiously in digoxin toxicity.
  • Calcium chloride more concentrated but requires central administration to avoid tissue necrosis.
  • Use of selective β1-blockers preferred over nonselective β-blockers in hyperkalemia risk patients.

ONGOING CARE

Monitoring

  • Recheck serum potassium every 2-4 hours until stable.
  • Monitor for recurrent hyperkalemia.

Diet

  • Restrict high-potassium foods (bananas, citrus, nuts, dried fruits, potatoes, tomatoes, salt substitutes).
  • Consult dietitian for low-K diet.

PROGNOSIS

  • Hyperkalemia is associated with poor outcomes in heart failure and CKD.
  • Risk of fatal arrhythmias if untreated.

COMPLICATIONS

  • Life-threatening cardiac arrhythmias.
  • Volume overload or intestinal necrosis from ion-exchange resins.

REFERENCES

  1. Palmer BF, Clegg DJ. Diagnosis and treatment of hyperkalemia. Cleve Clin J Med. 2017;84(12):934-942.
  2. Wong R, Banker R, Aronowitz P. Electrocardiographic changes of severe hyperkalemia. J Hosp Med. 2011;6(4):240.
  3. Viera AJ, Wouk N. Potassium disorders: hypokalemia and hyperkalemia. Am Fam Physician. 2015;92(6):487-495.
  4. Khanagavi J, Gupta T, Aronow WS, et al. Hyperkalemia among hospitalized patients and association between duration of hyperkalemia and outcomes. Arch Med Sci. 2014;10(2):251-257.
  5. Sterns RH, Rojas M, Bernstein P, et al. Ion-exchange resins for the treatment of hyperkalemia: are they safe and effective? J Am Soc Nephrol. 2010;21(5):733-735.
  6. Ingelfinger JR. A new era for the treatment of hyperkalemia? N Engl J Med. 2015;372(3):275-277.
  7. Bushinsky DA, Williams GH, Pitt B, et al. Patiromer induces rapid and sustain potassium lowering in patients with chronic kidney disease and hyperkalemia. Kidney Int. 2015;88(6):1427-1433.
  8. 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.
  9. Montford JR, Linas S. How dangerous is hyperkalemia? J Am Soc Nephrol. 2017;28(11):3155-3165.
  10. Ramos CI, González-Ortiz A, Espinosa-Cuevas A, et al. Does dietary potassium intake associate with hyperkalemia in patients with chronic kidney disease? Nephrol Dial Transplant. 2021;36(11):2049-2057.