Hypokalaemia

Last Updated on August 24, 2022

Introduction

• Daily requirement of potassium = 1mmol/kg (i.e. body weight)

Definition

• Hypokalaemia is serum potassium less than 3.5 mmol/L
• Severe hypokalaemia: Serum K+ <2.5 mmol/L

Common Causes

(i) Inadequate intake

(ii) Loss

GI loss
• Excessive vomiting / diarrhoea
• High output stoma

Loss from skin
• Burns

(iii) Redistribution into cells

• ß-agonist e.g. Salbutamol
• Insulin treatment

Investigations

Blood

• ABG / VBG

ECG

• Prolonged PR interval
• Prolonged QT interval
• Diffuse ST depression
• Prominent U wave

Management

Fast correction (with IV KCl)

• Correction = deficit + maintenance

Tips

Q&A