Last Updated on August 19, 2026
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 e.g. acute gastroenteritis, dengue, laxative abuse, etc.
•
Excessive
• High output stoma
Loss from skin
• Burns
(iii) Redistribution into cells
• ß-agonist e.g. Salbutamol e.g. IVI actrapid in DKA Types of insulin 🚪 Prandial insulin (Bolus) 🚪 Basal insulin 🚪 Premixed insulin Source: CPG Management of Type 2 Diabetes Mellitus
•
Insulin treatment
• Short acting: Actrapid®, Humulin R, Insuman R, Insugen R
• Rapid analogue: Aspart (Novorapid®), Lispro (Humalog®), Glulisine (Apidra®)
• Intermediate-acting: Insulatard®, Hululin N, Insuman N, Insugen N
• Long-acting analogue: Glargine, Detemir, Degludec
• Mixtard 30, Humulin 30/30, Novomix 30, Humalog mix 25/75, Humalog mix 50/50
Investigations
Blood
•
ABG / VBG
To look for acid base status
ECG
• Prolonged PR interval
• Prolonged QT interval
• Diffuse ST depression
• Prominent U wave
Management
Fast correction (with IV KCl)
• Correction =
deficit
Formula: (4 – measured serum potassium) × 0.4 × body weight in kg / 13.4 Formula of daily requirement of potassium: 1 mmol × body weight / 13.4
• Example: body weight is 60 kg. Daily requirement = 1 × 60 / 13.4 = 4.5 g
• Therefore, if that patient on IVD 4 pints normal saline over 24 hours, 4.5g/4 pints = each pint will have 1 g KCl added
Tips
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Q&A
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