Hypokalaemia is said to have occurred when serum potassium levels are persistently below 3.5mmol/L.
Causes of hypokalaemia
- Inadequate dietary intake (rare)
- Gastrointestinal fluid loss (vomiting, diarrhoea, fistulae)
- Renal loss (diuretics, uncontrolled diabetes mellitus)
- Systemic metabolic alkalosi
Clinical features for hypokalaemia include the following:
- Muscular weakness
- Paralytic ileus
- Cardiac arrhythmias
- Low serum potassium
- Elevated serum bicarbonate
- Low serum chloride
- ST segment depression and appearance of V waves on ECG
- Urea and electrolytes
- Treat cause where possible.
- If necessary give oral potassium (Slow K), 80–100mmol daily or intravenous (at a rate of infusion not to exceed 25mmol/hr).
- Care must be taken in patients with renal failure to avoid hyperkalaemia.
- Never give potassium IV as a bolus. The patient will have cardiac arrest.