View source for Anion gap metabolic acidosis

== Definition ==

* Metabolic acidosis with an increased anion gap

== Differential Diagnosis ==

=== GOLDMARK ===

* Glycols: [[Ethylene glycol toxicity|ethylene]] ([[AKI]], osmolar gap) and [[Propylene glycol toxicity|propylene]] (osmolar gap)
* Oxoproline ([[Acetaminophen overdose|acetaminophen]])
* L-lactic acidosis: rapid-onset
* D-lactic acidosis: bowel stasis
* [[Methanol toxocity|Methanol]]: visual changes, osmolar gap
* [[ASA]]
* Renal failure
* [[Ketoacidosis]]

=== Biochemical Approach ===

* Lactic acidosis
** Type A: impaired tissue oxygenation
*** Systemic hypoperfusion and shock
** Type B
*** [[Metformin]]
*** Malignancy
*** Chronic alcohol intake (mild)
*** [[HIV]] medications
*** IV epinephrine
*** Mitochondrial dysfunction
*** [[Propofol]]
*** [[Linezolid]]
** [[D-lactic acidosis]]: short bowel syndrome
* Ketoacidosis
** [[Diabetic ketoacidosis]] (DKA)
** [[Alcoholic ketoacidosis]]
** [[Starvation ketoacidosis|Starvation]]
* Toxins
** Salicylates
** Acetaminophen (5-oxoproline)
** Methanol (formic acid)
** Ethylene glycol (glycolic acid and oxalic acid)
* Renal failure (acute or chronic)

== Clinical Manifestations ==

* Rapid onset: lactic acidosis
* Osmolar gap: methanol, ethanol, ethylene glycol
* Visual changes: methanol
* AKI: ethylene glycol
* Normal pH: ethanol
* Slow bowel transit: D-lactic acidosis

== Investigations ==

* Serum electrolytes
** Anion gap
** Delta-delta: increase in anion gap should be matched by equal decrease in bicarb
* Serum osmolarity
* Lactate, to rule out lactic acidosis

== Management ==

* Treat underlying cause

[[Category:Nephrology]]
[[Category:Investigations]]