Acid Base 2

Acid Base

Anion Gap = measured cations - measured anions
in practice: AG = Na+ - (HCO3- + Cl-)

Metabolic Acidosis
AG metabolic acidosis  =  dec. HCO3- with nl chloride and unmeasured anion; e.g., lactate

"make it "

•Uremia: failure to excrete endogenous organic acids
• Ketoacidosis: metabolism of fatty acids in diabetics or alcoholics
• Lactate: tissue hypoxia from sepsis, CO or cyanide poisoning, cardiac arrest, etc

"or take it"

• Ethanol
• Methanol
• Ethylene glycol
• Salicylates
• Paraldehyde




Traditional mnemonic:
– E- ethanol
– M- methanol
– U- uremia
– D- diabetic ketoacidosis
– P- paraldehyde
– I- Inhalants (CO in particular)
– L- Lactate
– E- Ethylene glycol
– S- Salicylates

Non AG metabolic acidosis = dec. HCO3- with inc. Cl-; e.g., aceylzolamide inhibition of carbonic anhydrase in proximal tubule


• GI tract
– Diarrhea
– Pancreatic fistula
– Ureteral diversion into ileal loop (bladder removal with ureter put into ileum)


• Kidney
– Renal tubular acidosis
– Carbonic anhydrase inhibitor (acetazolamide/Diamox)


Osmolar Gap  = calculated - measured osmolarity
Measurement of the serum osmolal gap is most useful in patients with a high anion gap metabolic acidosis, particularly when methanol or ethylene glycol poisoning is suspected

"make it"

Ketoacids
Uremia

"or take it"

Drug metabolites
Methanol, Ethanol
Other alcohols

Metabolic Alkalosis

vomiting = H+ loss.  and inc. plasma HCO3
volume depletion make alkalosis worse due to RAAS system - low urine chloride

contraction alkalosis - vomiting

Hyperaldosteronism