Symptoms
Clinical signs and symptoms of potassium overdosage include:
Paraesthesia of the extremities, listlessness, mental confusion, weakness or heaviness of the legs, flaccid paralysis, cold skin, grey pallor, peripheral vascular collapse, fall in blood pressure, cardiac arrhythmias and heart block, due to which patients may deteriorate rapidly.
Extremely high plasma potassium concentrations (8-11 mmol/litre) may cause death from cardiac depression, arrhythmias or arrest.
All drugs containing potassium should be withdrawn and potassium-sparing diuretics discontinued.
Treatment
Serum concentrations may be reduced by infusion of 300 – 500 mls per hour of 10% - 25% glucose solutions containing up to 10 units of insulin for each 20 g of glucose, or by the infusion of sodium bicarbonate solution.
Cardiac arrhythmias or a serum concentration above 6.5 mmol/litre, require immediate attention and may be treated by intravenous injection over 1 – 5 minutes of 10 – 20 ml of 10% Calcium Gluconate Injection B.P. with E.C.G. monitoring. Mild hyperkalaemia may be treated with sodium polystyrene sulphonate, a cation-exchange resin administered by mouth or as an enema. If the above measures fail, haemodialysis or peritoneal dialysis may be required.
Monitoring
• Measure urea, electrolytes and creatinine
• Monitor potassium levels regularly (2 to 3 hourly if raised )
• Continuous 12 lead ECG
• Observe asymptomatic patients for at least 6 hours