Indications:
The monitoring of serum potassium can appreciate the blood level of a fundamental ke cation for muscle function like intestinal transit: potassium (K).
But it also allows monitoring of treatments could cause hypokalemia (in the case of diuretics, laxatives) or hyperkalemia (ACE inhibitor, anti-aldostérones, angiotensin II antagonists).
It is also an essential part of monitoring the diabetic patient, renal failure or carrying a heart disease.
This may be the end of the search for a primary or secondary aldosteronism before hypertension.
Principle:
Kidney regulates the potassium levels; here is dose plasma concentrations.
Technique:
It is that of blood electrolytes. Sampling 5 mL of venous blood on heparin tube:
– Quickly send to the laboratory.
– Reduce to a minimum the time of the withers;
– Do not make a fist;
– Absolutely avoid hemolysis.
Results:
Normal values:
From 3.8 to 5 mEq / L.
Pathological changes:
– Hypokalaemia:
– Medication: diuretics, laxatives, taking licorice,
– Kidney disease,
– Crohn’s disease,
– Cushing’s disease,
– Prolonged diarrhea;
– Hyperkalemia:
– Medication: diuretics like spironolactone,
– renal failure,
– Adrenal insufficiency,
– Addison’s disease,
– Metabolic acidosis.
Cost:
B15.
Practical advice:
Haemolysis, thrombocytosis or leukocytosis misrepresent hyperkalemia.
When hypokalemia is less than 3.5 mEq / L:
– If urinary potassium is less than 15 mEq / 24 h: this is the sign of extrarenal loss;
– If the kaliuresis than 15 mEq / 24 h, the loss is followed renal or taking diuretics.
When hyperkalemia is greater than 5.5 mEq / L, and the kaliuresis greater than 200 mEq / 24 h, there is a risk of serious cardiac disorders, which can lead to cardiac arrest.
Hypo- or hyperkalemia are biological emergencies: the transmission of results to the prescribing physician must be made as soon as possible.
