Hyperkalaemia Flashcards
what is the definition of hyperkalaemia?
Significant hyperkalemia is defined as a serum potassium value >6.0 mmol/L (>6.0 mEq/L). Moderate hyperkalemia is defined as serum potassium values in the 5.0 to 6.0 mmol/L (5.0-6.0 mEq/L) range. Small changes in serum potassium values can have significant muscular and cardiac effects when significant hyperkalaemia is present.
what is the aetiology of hyperkalaemia?
most commonly due either to high intake of potassium in the setting of decreased renal excretion or to extracellular redistribution of potassium from intracellular locations. There is a limited correlation between an elevated serum potassium value and an excess in total body potassium stores. Clinical manifestations of hyperkalemia are uncommon with values <6.0 mmol/L (<6.0 mEq/L).
Increased intake of potassium in association with decreased renal excretion
Decreased cellular entry of potassium or increased exit of potassium from cells
A test-tube phenomenon leading to so-called pseudohyperkalemia.
what are the key presentations of hyperkalaemia?
Common acute manifestations of significant hyperkalemia include muscle weakness and ECG changes, with the latter having the potential to progress to a life-threatening arrhythmia
what are the signs of hyperkalaemia?
ECG changes - tall tented t-waves and short p waves
History of renal failure, muscle trauma, chemotherapy, diabetes
what are the symptoms of hyperkalaemia?
muscle weekness
what are the first line and gold standard investigations for hyperkalaemia?
History taking to detect underlying cause
Basic metabolic panel
Serum calcium
FBC
ECG - first degree heart block, flattened or absent P waves, peaked T waves, ST segment depression, wide QRS, ventricular tachycardia, bradycardia and eventually cardiac arrest
what are the differential diagnoses for hyperkalaemia?
Chronic kidney disease, diabtetic ketoacidosis/hyperosmolar hyperglycemic state, drug related decreased cellular entry, potassium supplementation with underlying renal dysfunction, drug related reduced urinary potassium excretion
how is hyperkalaemia managed?
Significant hyperkalaemia represents a medical emergency, and an ECG should be obtained to establish whether cardiotoxicity is present. Continuous ECG monitoring should occur until serum potassium values have been brought into a safe range and cardiotoxicity has resolved.
Treat underlying cause
