Hyperkalemia is a condition of elevated serum potassium concentration (> 5.5 mmol/L) due primarily to reduced excretion of urinary potassium, increased potassium release from cells, and excess potassium intake.

Signs and symptoms include muscle weakness, paralysis, and cardiac abnormalities (irregular conduction and arrhythmias). Hyperkalemia is most commonly seen in individuals with:

• Acute or chronic kidney disease.
• Diabetes (type 1 or type 2).
• Chronic NSAID usage.
• Concurrent use of beta blockers, angiotensin-converting enzyme (ACE) inhibitors / angiotensin II receptor blockers (ARBs), and potassium-sparing diuretics.

ECG changes of hyperkalemia do not reliably correlate with potassium levels, but mild elevation (5.5-6.5 mmol/L) may cause peaked T waves, shortened QT interval, and ST-segment depression. At higher levels of potassium (< 8.0 mmol/L), the ECG may demonstrate peaked T waves, PR prolongation with decreased P waves, and widening QRS.