Anion Gap and Osmolar Gap (High)
Revision as of 11:56, 23 July 2016 by Neil.m.young (talk | contribs) (Text replacement - "==Diagnosis==" to "==Evaluation==")
Calculations
Anion Gap
AG = Na - (Cl + HCO3)
Calculated Osm
Calculated Osm = 2 x Na + (glu/18) + (BUN/2.8) + (ethanol/4.6) + (methanol/2.6) + (ethylene glycol/5) + (acetone/5.5) + (isopropanol/5.9)
- Normal = 275-295
Osmolal Gap
Osmolal Gap = measured osm - calculated osm
- Normal = (-)14-10 mOsm/L
Differential Diagnosis
Toxicological
- Methanol
- Ethanol glycol
- Aspirin (Salicylate) Toxicity
- Iron
- INH
- Paraldehyde
- Alcoholic Ketoacidosis
- Inhalants - CN, CO, Hydrogen Sulfide
- Toluene
Non-Toxicological
CAT MUDPILERS
- C-Cyanide
- A-ASA, Alcohol
- T-Toluene
- M-Methanol, Metformin
- U-Uremia
- D-DKA
- P-Paraldehyde, Post-ictal lactic acidosis (transient, 60-90 min), Phenformin (withdrawn in 1970s)
- I-Iron, INH, Inhalants, Inborn Errors
- L-Lactic Acidosis
- E-Ethylene glycol, Ethanol
- R-Rhabdomyolysis
- S-Salicylates, Solvents, Starvation
Evaluation
Toxic Alcohols Anion/Osmolar Gaps
| Osmolar gap | Anion gap | Management | |
|---|---|---|---|
| Ethanol | + | + if ketoacidosis | Mainly supportive |
| Ethylene glycol | + | + | Fomepizole, Thiamine, Pyridoxine, +/- Dialysis |
| Methanol | + | + | Fomepizole or ethanol, Folinic acid, +/- Dialysis |
| Isopropyl alcohol | + | - | Mainly supportive |