Chempath - Anion Gap Flashcards
What are the causes of a raised anion gap metabolic acidosis?
GOLD MARK
G- Glycols (ethylene glycol and propylene glycol)
O - Oxoproline (chronic paracetamol use, usually malnourished women)
L- L-lactate (sepsis)
D- D-lactate (short gut syndrome)
M- Methanol
A- Aspirin (salicyclates)
R - Renal failure
K- Ketones
What acid base abnormality will salicyclate overdose cause?
Mixed respiratory alkalosis (drives the respiratory centre to increase ventilation) and metabolic acidosis (increased production of lactic acid and acetyl CoA)
What are the causes of a metabolic acidosis normal anion gap?
Bicarb loss replaced with chloride (normal gap)
- Addison’s
- Bicarb loss (diarrhea, laxative abuse, RTA)
- Chloride gain (0.9% NaCl)
- Drugs (acetazolamide)
Why does Addison’s cause normal gap metabolic acidosis?
- Decreased aldosterone function
- Decreased Na+ plasma concentration
- Increased K+ plasma concentration
Decreased Na+ plasma reabsorption in the tubules leads to decreased H+ excretion in the tubules (acidosis)
- Increased HCO3- excretion (due to decreased H+ reabsorption)
- Unchanged Cl-
Overall the decrease in serum Na+ and decreased in HCO3- balance each other out and lead to a normal gap metabolic acidosis
How is the osmolar gap calculated?
2(Na+ + K+) + urea + glucose (calculated)
Minus serum osmolality
Should be <10, if >10 suggests presence of something that can’t be directly measured using tests