Metabolic acidosis DDx
Normal anion gap metabolic acidosis
- U – Ureteric diversion
- S – Small bowel fistula
- E – Extra chloride (ED resuscitation) or HCl ingestion
- D – DKA (resolving)
- C – Carbonic anhydrase inhibitors
- A – Addisons (Type 4 RTA)
- R – Renal tubular acidosis types 1, 2, and 4
- P – Pancreatic fistula
Increased anion gap metabolic acidosis
- M – Methanol (formic acid), metformin
- U – Uraemia (including aminoglycosides)
- R – Renal failure (Uric acid)
- K – Ketoacidosis (alcohol, diabetes (acute), starvation)
- L – Lactic acidosis
- E – Ethanol
- S – Salicylates
- E – Ethylene glycol (glycolic acid)
- P – Paraldehyde, propylene glycol
- T – Toluene
- I – Iron, isoniazid
- C – Cyanide and carbon monoxide
Low anion gap
- Increase in unmeasured cations (Increased Li, K, Ca, Mg, and IgG)
- Lithium toxicity
- Hypercalcaemia
- Hypermagnesaemia
- Hyperkalaemia
- IgG (Multiple Myeloma)
- Decreased unmeasured anions (Decreased PO4, albumin)
- HYPOalbuminaemia, HYPOphosphatemia
- Chloride over-estimation (anion)
- Bromide toxicity (Read as increased chloride)
- Iodide toxicity
- Hypercholesterolemia
Clinical
- Respiratory
- Hyperventilation
- Shift of Oxy-Hb curve to right
- Cardiovascular
- Myocardial depression
- Tissue catecholamine resistance
- Pulmonary vasoconstriction
- Hyperkalaemia
Correction
- Treat underlying cause
- Supportive therapy
- IV bicarbonate controversial – usually not helpful
References and Links
- Acid-Base: ABG analysis – Anion Gap – SID – NAGMA
- Metabolic acidosis: Overview – evaluation – DDx
- Metabolic alkalosis: Overview – evaluation – DDx
- Respiratory acidosis: Overview – DDx
- Respiratory alkalosis: Overview – DDx
Critical Care
Compendium
