Hypokalaemia

• The diagnosis of hypokalaemia is based on a laboratory sample of plasma potassium <3.5 mmol/L
• The severity can be divided as follows:

  • Mild: 3.0-3.4 mmol/L
  • Moderate: 2.5-2.9 mmol/L
  • Severe: < 2.5 mmol/L or symptomatic
• ECG changes associated with hypokalaemia:

  • Prominent U wave
  • Flat T waves
  • ST depression
  • Prolonged PR interval
• Patients with severe hypokalaemia or ECG changes require IV potassium replacement
• Causes of hypokalaemia:

  • Diarrhoea
  • Vomiting
  • Loop and thiazide diuretics
  • Increased insulin
• Symptoms of Hypokalaemia:

  • Fatigue
  • Generalised weakness
  • Muscle cramps and pain
  • Palpitations
  • Constipation
  • Severe - arrhythmias and muscle paralysis