12th March 2024

High anion gap metabolic acidosis

The anion gap is calculated as the total number of sodium and potassium ions minus the total number of chlorine and bicarbonate ions. A normal anion gap ranges from 8-16 mEq/l. The mnemonic CAT MUDPILES is often used to remember the causes of high anion gap metabolic acidosis:

• Carbon monoxide/ cyanide
• Aminoglycosides
• Toluene (found in acrylics, glue and paint)
• Methanol
• Uraemia
• Diabetic ketoacidosis
• Paracetamol/ Propylene glycol
• Infection/Iron/Isoniazid/ Inborn errors of metabolism
• Lactic acidosis
• Ethylene glycol
• Salicylates