ABG Analysis

Question 1

Causes of High Anion gap Metabolic Acidosis:

CAT MUDPILES

Answer 1

C: Carbon monoxide, Cyanide, Congenital Heart Failure
A: Aminoglycosides
T: Teophylline, Toluene(Glue-sniffing)
M: Methanol
U: Uraemia
D: DKA, Alcoholic ketoacidosis, Starvation ketoacidosis
P: Paracetamol/acetaminophen, Phenformin, Paraldehyde
I: Iron, Isoniazid, Inborn errors of metabolism
L: Lactic acidosis
E: Ethanol(due to lactic acidosis), Ethylene glycol
S: Salicylates, Aspirin

Question 2

Causes of Lactic Acidosis(commonest cause of high anion gap metabolic acidosis):

Answer 2

1. Tissue hypoperfusion
   - Trauma with major haemorrhage
   - Septic shock
2. Tissue hypoxia
   - Hypoxaemia
   - Carbon monoxide/cyanide poisoning
3. Hepatic failure
4. Renal failure
5. Ethylene glycol/methanol poisoning
6. Cocaine/amphetamines
7. Salicylate poisoning/iron poisoning
8. Biguanides(metformin)
9. Isoniazid
10. Strenuous exercise

Question 3

Causes of normal anion gap Metabolic Acidosis:

Answer 3

1. Chronic Diarrhoea
2. Pancreatic/intestinal fistula
3. Renal tubular acidosis
4. Acetazolamide