Hypokalaemia
Clinical signs
- Muscle weakness, reduced tendon reflexes, muscle tetany
- Intestinal ileus, constipation, abdominal distention
- ECG: Flat T-waves
- Polyuria (urine concentration defect)
- Hyperglycaemia,
- Anorexia, nausea, vomiting
Pathogenesis
- Decreased intake
- Transcellular K+ shift from extra cellular volume to intra cellular volume
e.g.
- Alkalosis
- Insuline
- Beta-catecholamines
- Increased excretion
a. Renal:
e.g.
- Tubular disturbances (e.g. Bartter, Gitelman)
- Steroids (e.g. hyperaldosteronism)
- Diuretics
b. Non-renal:
e.g
- Vomiting
- Diarrhoea
- Laxative abuse
Treatment
- Increase KCl content of iv fluid, or give enteral K supplement
- If patient is on diuretics ensure that Spironolactone or Amiloride is used
Bolus Intravenous KCl-correction
Is only used in children with severe hypokalaemia (<2.5 mmol/L) AND poor cardiac function or a tendency to arrhythmias.
- Only given via central access
- Bolus: 0.25mmol/kg over 60 minutes. Check ECG!
- Infusion: max rate: 0.5 mmol/kg/hr -> Check K+ levels hourly!
- Max. concentration: 50 mmol/100ml
- Rapid infusion of KCl causes fatal cardiac arrhythmias!
- on rare occasions it can be given peripherally, max concentration: 6mmol/100ml