Metabolic acidosis: Difference between revisions

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==DDX==
==Clinical Features==
===Gap===
*Compensatory respiratory tachypnea
#Lactic acidosis
 
#Renal failure
==Differential Diagnosis==
#Ketoacidosis
{{Anion gap metabolic acidosis}}
##DM
##ETOH
##Starvation
##High fat diet
#Tox ingestion
##Inc osm gap
###Methanol
###Ethylene glycol
##Nl osm gap
### Salicylate
###Paraldehyde
###Cyanide


===Non-gap===
===Non-gap===
# Hyperkalemia
{{Non anion gap acidosis}}
## Resolving DKA
 
## Early uremic acidosis
==Evaluation==
## Early obstructive
;Osm gap = measured osm - calculated osm (normal 10-15)
## RTA Type IV
;Calculated Osm = 2(Na)+(glucose/18)+(BUN/2.8)+(BAL/5)
## Hypoaldo
## K-sparing diuretics
# Hypokalemia
## RTA Type I
## RTA Type II
## Acetazolamide
## Acute diarrhea
### (May be assoc with gap if hypoperfusion -> lactic acidosis)


==Treatment==
*Primary acidosis if pH <7.38
Treat source
*HCO3 <24 = metabolic acidosis
*Always determine if there is another acid/base process occurring
**Primary respiratory acidosis if pCO2 > pCO2expected
**Primary respiratory alkalosis if pCO2 < pCO2expected
***use Winter's formula: PCO2 (expected) = (1.5 x [HCO3–] + 8) ± 2
***In acute setting PCO2 should fall by 1 mmHg for every 1 mEq fall in HCO3
**Concurrent metabolic alkalosis if delta-delta > 28
**Delta-Delta = (AG - 12) + HCO3


===Bicarbonate Indications===
==Management==
#Bicarb <4
*Treat source
#pH <7.20 + Sx shock/myocardial irritability
*Correct any [[respiratory acidosis]]
#Severe hyperchloremic acidemia + Sx shock/myocardial irritability
*[[Bicarbonate]]
**HCO3 dose in mEq = 0.5(wt in kg) x (24 - measured HCO3)
**Each bicarb 0.5mEq/kg causes 1 meq/L rise in HCO3
**Consider for:
***Bicarb <4
***pH <7.20 AND shock/myocardial irritability
***Severe hyperchloremic acidemia
***lower threshold with non-AG acidosis (greater HCO3 loss)
****Lost bicarbonate would take days to replenish


==Source ==
==See Also==
2/21/06 DONALDSON (adapted from Tintinalli)
*[[Acid-base disorders]]


==References==
<references/>
[[Category:FEN]]
[[Category:FEN]]
[[Category:Toxicology]]

Latest revision as of 15:12, 22 July 2017

Clinical Features

  • Compensatory respiratory tachypnea

Differential Diagnosis

Anion gap metabolic acidosis

Non-gap

Evaluation

Osm gap = measured osm - calculated osm (normal 10-15)
Calculated Osm = 2(Na)+(glucose/18)+(BUN/2.8)+(BAL/5)
  • Primary acidosis if pH <7.38
  • HCO3 <24 = metabolic acidosis
  • Always determine if there is another acid/base process occurring
    • Primary respiratory acidosis if pCO2 > pCO2expected
    • Primary respiratory alkalosis if pCO2 < pCO2expected
      • use Winter's formula: PCO2 (expected) = (1.5 x [HCO3–] + 8) ± 2
      • In acute setting PCO2 should fall by 1 mmHg for every 1 mEq fall in HCO3
    • Concurrent metabolic alkalosis if delta-delta > 28
    • Delta-Delta = (AG - 12) + HCO3

Management

  • Treat source
  • Correct any respiratory acidosis
  • Bicarbonate
    • HCO3 dose in mEq = 0.5(wt in kg) x (24 - measured HCO3)
    • Each bicarb 0.5mEq/kg causes 1 meq/L rise in HCO3
    • Consider for:
      • Bicarb <4
      • pH <7.20 AND shock/myocardial irritability
      • Severe hyperchloremic acidemia
      • lower threshold with non-AG acidosis (greater HCO3 loss)
        • Lost bicarbonate would take days to replenish

See Also

References