To summarize, classic ECG changes associated with hyperkalemia are seen in the following progression: peaked T wave, shortened QT interval, lengthened PR interval, increased QRS duration, and eventually absence of the P wave with the QRS complex becoming a sine wave. Bradycardia, junctional rhythms and QRS widening are particularly associated with increased risk of adverse outcomesThe serum potassium concentration at which electrocardiographic changes develop is somewhat variable. Although the factors influencing the effect of serum potassium levels on cardiac electrophysiology are not entirely understood, the concentrations of other electrolytes, as well as levels of catecholamines, play a major role.ECG findings are not a reliable finding in hyperkalemia. In a retrospective review, blinded cardiologists documented peaked T-waves in only 3 of 90 ECGs with hyperkalemia. Sensitivity of peaked-Ts for hyperkalemia ranged from 0.18 to 0.52 depending on the criteria for peak-T waves. Prevention
Preventing recurrence of hyperkalemia typically involves reduction of dietary potassium, removal of an offending medication, and/or the addition of a diuretic (such as furosemide or hydrochlorothiazide). Sodium polystyrene sulfonate and sorbitol (combined as Kayexalate) are occasionally used on an ongoing basis to maintain lower serum levels of potassium though the safety of long-term use of sodium polystyrene sulfonate for this purpose is not well understood.High dietary sources include vegetables such as avocados, tomatoes and potatoes, fruits such as bananas, oranges and nuts. Treatment
Emergency lowering of potassium levels is needed when new arrhythmias occur at any level of potassium in the blood, or when potassium levels exceed 6.5 mmol/L.
Elimination
Severe cases require hemodialysis, which are the most rapid methods of removing potassium from the body. These are typically used if the underlying cause cannot be corrected swiftly while temporising measures are instituted or there is no response to these measures. Loop diuretics (furosemide, bumetanide, torasemide) and thiazide diuretics (e.g., chlortalidone, hydrochlorothiazide, or chlorothiazide) can increase kidney potassium excretion in people with intact kidney function.Potassium can bind to a number of agents in the gastrointestinal tract. Sodium polystyrene sulfonate with sorbitol (Kayexalate) has been approved for this use and can be given by mouth or rectally. However, high quality evidence to demonstrate the effectiveness of sodium polystyrene are lacking, and use of sodium polystyrene sulfonate, particularly with high sorbitol content, is uncommonly but convincingly associated with colonic necrosis. There are no systematic studies (>6 months) looking at the long-term safety of this medication.Patiromer is taken by mouth and works by binding free potassium ions in the gastrointestinal tract and releasing calcium ions for exchange, thus lowering the amount of potassium available for absorption into the bloodstream and increasing the amount lost via the feces. The net effect is a reduction of potassium levels in the blood serum.Sodium zirconium cyclosilicate is a medication that binds potassium in the gastrointestinal tract in exchange for sodium and hydrogen ions. Onset of effects occurs in one to six hours. It is taken by mouth. Epidemiology
Hyperkalemia is rare among those who are otherwise healthy. Among those who are in hospital, rates are between 1% and 2.5%.