It is associated with an increased mortality, whether due to hyperkalaemia itself or as a marker of severe illness, especially in those without chronic kidney disease. The word hyperkalemia comes from hyper- high + kalium potassium + -emia blood condition. Signs and symptoms
The symptoms of an elevated potassium level are generally few and nonspecific. Nonspecific symptoms may include feeling tired, numbness  and weakness. Occasionally palpitations and shortness of breath may occur. Hyperventilation may indicate a compensatory response to metabolic acidosis, which is one of the possible causes of hyperkalemia. Often, however, the problem is detected during screening blood tests for a medical disorder, or after hospitalization for complications such as cardiac arrhythmia or sudden cardiac death. High levels of potassium (> 5.5 mmol/L) have been associated with cardiovascular events. Causes
Ineffective elimination
Decreased kidney function is a major cause of hyperkalemia. This is especially pronounced in acute kidney injury where the glomerular filtration rate and tubular flow are markedly decreased, characterized by reduced urine output. This can lead to a dramatically elevated potassium in conditions of increased cell breakdown as the potassium is released from the cells and cannot be eliminated in the kidney. In chronic kidney disease, hyperkalemia occurs as a result of reduced aldosterone responsiveness and reduced sodium and water delivery in distal tubules.Medications that interfere with urinary excretion by inhibiting the renin–angiotensin system is one of the most common causes of hyperkalemia.
The effect of these measures tends to be short-lived, but may temporise the problem until potassium can be removed from the body. Insulin (e.g. intravenous injection of 10 units of regular insulin along with 50 mL of 50% dextrose to prevent the blood sugar from dropping too low) leads to a shift of potassium ions into cells, secondary to increased activity of the sodium-potassium ATPase. Its effects last a few hours, so it sometimes must be repeated while other measures are taken to suppress potassium levels more permanently. The insulin is usually given with an appropriate amount of glucose to help prevent hypoglycemia following the insulin administration, though hypoglycaemia remains common especially in the context of acute or chronic renal impairment and capillary blood glucose measurements should be taken regularly after administration to identify this. Salbutamol (albuterol), a β2-selective catecholamine, is administered by nebuliser (e.g. 10–20 mg). This medication also lowers blood levels of K+ by promoting its movement into cells, and will work within 30 minutes. It is recommended to use 20 mg for maximum potassium lowering effect, but to use lower doses if the patient is tachycardic or has ischaemic heart disease. Note that 12-40% of patients do not respond to salbutamol therapy for reasons unknown, especially if on beta-blockers, so it should not be used as monotherapy
Sodium bicarbonate may be used with the above measures if it is believed the person has metabolic acidosis, though time to effectiveness is longer and its use is controversial.