Hypokalaemia

E87.6

• Description
• Diagnostic criteria
• Medicine treatment

DESCRIPTION

Causes include:

• prolonged decreased intake and protein energy malnutrition;
• increased renal excretion: renal tubular acidosis, amphoteracin B and diuretics;
• increased extrarenal losses;
• transmembrane shifts: ß₂ stimulants, alkalosis; and
• mineralocorticoid excess.

DIAGNOSTIC CRITERIA

Clinical

• Cardiac arrhythmias, especially with digitalis.
• Neuromuscular dysfunction, e.g. muscle weakness.
• Renal: impairment of urine concentrating or diluting ability.

Investigations

• Serum potassium <3.0 mmol/L.

MEDICINE TREATMENT

See Diarrhoea, acute.

Severe respiratory paralysis and or cardiac arrhythmias:

• Potassium chloride, IV, <1 mEq/kg/hour.
  • ECG monitoring.
  • Potassium concentration should not be >40 mmol/L/infusion.
  • Never give potassium as an IV bolus.

Less critical situations to correct potassium deficit over 2–3 days:

• Potassium chloride, oral, 2–6mEq/kg/day.

Note: 1 g KCl = 13 mEq; 1 mL 15% KCl = 2mmol; 1 mEq = 1 mmol.