Anion Gap Metabolic Acidosis Flashcards
Albumin’s Effect
Binds cations, so for every decrease in serum albumin by 1g, expected anion gap decreases by 2.5
Stages of Ethylene Glycol Toxicity
Alcohol dehydrogenase (RL) converts to glycoaldehyde, aldehyde dehydrogenase converts to glycolic acid (stage 2, not before 12 hours, METABOLIC ACIDOSIS CAUSATIVE), converted glyoxylate -> oxalate (STAGE 3, FORMS CALCIUM OXALATE CRYSTALS, ACUTE TUBULAR NECROSIS ATN) not before 24 hours However glycolic acid can also have direct kidney effects
Osmolar Gap
Unidentified alcohol ingestion (like ethylene glycol, methanol, alcohol, isopropyl alcohol, proplene glycol) that hasn’t yet been metabolized. Calculated osm (Na x 2 + gluc/18 + BUN/3) and subtract from lab given. > 10 significant. Means still have chance to treat
4 Treatments for Ethylene Glycol Poisoning
Alcohol
Fomepizole (alcohol dehydrogenase inhibitor)
Buy time so can excrete if osm gap still there
Also bicarb infusion and hemodialysis if further along
Methanol Overdose
Converted to formaldehyde then formic acid (bad one) through same dehydrog enzymes, not different stages though. Eye shit but no nephrotoxicity
Methanol Treatment
Same as ethylene glycol, but also IV folic acid to metabolize formic acid. Eye loss = urgent hemodialysis
3 Salicylate Sources
Aspirin, oil of wintergreen, pepto-bismol
Salicylate Presentation
Tinnitius and nausea/vomiting
Kids metabolic acidosis, but adults will have mixed disorder w/ Primary Respiratory Alkalosis bc stimulates medullary respiratory center and secondary metabolic acidosis
Salicylate Treatment
No enzyme inhibition, so just enhance elimination. Bicarb rich solution/urinary alkalinization
Ketoacidosis
From starvation/diabetes/alcoholism
FFAs broken down to acetoacetic acid then beta hydroxybutyrate (also acetone which doesn’t contribute)
Diabetic Ketoacidosis
Exclusively in Type I, usually they don’t eat and then don’t think they need to take insulin
AG/OG in Ketoacidosis
AG increased, OG not
Urine Test for Ketoacidosis
Nitroprusside test, only detects acetoacetic acid and acetone but beta hydroxybutyrate (which is majority), so can underrepresent degree
Ketoacidosis Treatment
Hydration, then correct problem (insulin for diabetic, dextrose/carbs for alcohol), food for starvation
Urine Ketone Test w/ Treatment
Will initially rise as the beta hydroxy goes back to acetoacetic acid. Gets worse then gets better
Isopropanol
Contributes to OG bc alcohol, but produces acetone which isn’t an acid (but will test positive in urine)
Fruity breath and shit, nothing really needing to be done
2 Types Lactic Acidosis
Type A- hemodynamic/hypoxic. So like sepsis w/ hypotension/shock or organ or limb ischemia
Type B - Drug induced, hemodynamically stable, adequate O2, but lactic acid bc mt poisoned
5 Things that Cause Type B Lactic Acidosis
Biguanide Oral Hypoglycemic Medication (T2DM) like Metformin
Reverse Transciptase Inhibitors for HIV infection
Iron overdose (usually kid w/ iron supplements)
Isoniazid (INH)
Propylene glycol - preservative in IV drugs like Diazepam and shit, agitated and lactic acidosis w/out hypotension or sepsis
Special Aspect of Propylene Glycol Lactic Acidosis
Mixture of D/L isomers. Lab test only measures L, so will underestimate severity of acidosis
D-Lactic Acidosis
Short bowel syndrome, limited small bowel (resection or bypass or something) and intact colon. Carbs go straight to colon, G+ anaerobe lactobacilli feast and produce D-lactic acid.
After meal gets intoxicated, then resolves until they eat again
Lactic Acidosis Treatment
Normalize O2/hemodynamic/circ problems (Type A)
Bicarbonate as needed to keep pH > 7.2
Just kinda gotta wait for it to get removed (Type B)
Pyroglutamic Acid
Chronic ingestion of acetminophin, prolonged depletion of glutathione
Uremic Acidosis
Low GFR/impaired tubular function leads to retention of sulfur, phosphorous, and lactic acid, accumulating w/ their acids to cause acidosis
