Hyperkalemia

Hyperkalemia
Other names	Hyperkalaemia
Electrocardiography showing precordial leads in hyperkalemia.
Pronunciation	/ˌhaɪpərkeɪˈliːmiə/
Specialty	Critical care medicine, nephrology
Symptoms	Palpitations, muscle pain, muscle weakness, numbness[1][2]
Complications	Cardiac arrest[1][3]
Causes	Kidney failure, hypoaldosteronism, rhabdomyolysis, certain medications[1]
Diagnostic method	Blood potassium > 5.5 mmol/L, electrocardiogram[3][4]
Differential diagnosis	Pseudohyperkalemia[1][2]
Treatment	Medications, low potassium diet, hemodialysis[1]
Medication	Calcium gluconate, dextrose with insulin, salbutamol, sodium bicarbonate[1][3][5]
Frequency	~2% (people in hospital)[2]

Hyperkalemia is an elevated level of potassium (K⁺) in the blood.^[1] Normal potassium levels are between 3.5 and 5.0 mmol/L (3.5 and 5.0 mEq/L) with levels above 5.5 mmol/L defined as hyperkalemia.^[3][4] Typically hyperkalemia does not cause symptoms.^[1] Occasionally when severe it can cause palpitations, muscle pain, muscle weakness, or numbness.^[1][2] Hyperkalemia can cause an abnormal heart rhythm which can result in cardiac arrest and death.^[1][3]

Common causes of hyperkalemia include kidney failure, hypoaldosteronism, and rhabdomyolysis.^[1] A number of medications can also cause high blood potassium including spironolactone, NSAIDs, and angiotensin converting enzyme inhibitors.^[1] The severity is divided into mild (5.5–5.9 mmol/L), moderate (6.0–6.4 mmol/L), and severe (>6.5 mmol/L).^[3] High levels can be detected on an electrocardiogram (ECG).^[3] Pseudohyperkalemia, due to breakdown of cells during or after taking the blood sample, should be ruled out.^[1][2]

Initial treatment in those with ECG changes is salts, such as calcium gluconate or calcium chloride.^[1][3] Other medications used to rapidly reduce blood potassium levels include insulin with dextrose, salbutamol, and sodium bicarbonate.^[1][5] Medications that might worsen the condition should be stopped and a low potassium diet should be started.^[1] Measures to remove potassium from the body include diuretics such as furosemide, potassium-binders such as polystyrene sulfonate (Kayexalate) and sodium zirconium cyclosilicate, and hemodialysis.^[1] Hemodialysis is the most effective method.^[3]

Hyperkalemia is rare among those who are otherwise healthy.^[6] Among those who are hospitalized, rates are between 1% and 2.5%.^[2] 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.^[7][6] The word hyperkalemia comes from hyper- 'high' + kalium 'potassium' + -emia 'blood condition'.^[8][9]