Metabolic acidosis resident survival guide: Difference between revisions

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{{SI}}
{{CMG}}; {{AE}} {{Ochuko}}
{{CMG}}; {{AE}} {{Ochuko}}


==Definition==
==Overview==
Metabolic acidosis is a state in which the blood [[pH]] is low (less than 7.35) due to increased production of [[hydrogen|H<sup>+</sup>]] by the body or the inability of the body to form [[bicarbonate]] (HCO<sub>3</sub><sup>-</sup>) in the [[kidney]].
Metabolic acidosis is a state in which the blood [[pH]] is low (less than 7.35) due to a decreased blood concentration of [[bicarbonate]].


==Causes==
==Causes==
===Life Threatening Causes===
===Life Threatening Causes===
*[[Diabetic ketoacidosis]]
*[[Diabetic ketoacidosis]]
*[[Ethylene Glycol poisoning]]
*[[Ethylene glycol poisoning]]
*[[Lactic acidosis]]
*[[Lactic acidosis]]
*[[Methanol]]
*[[Methanol]] ingestion


===Common Causes===
===Common Causes===
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The mnemonic for the most common causes of a normal-anion gap metabolic acidosis is "DURHAM."
The mnemonic for the most common causes of a normal-anion gap metabolic acidosis is "DURHAM."


* '''D'''- [[Diarrhea]]
* '''D'''- [[Diarrhea]], dilutional (rapid infusion of IV fluids that are free of bicarbonate)
 
* '''U'''- [[Ureteral diversion]]
* '''U'''- [[Ureteral diversion]]
* '''R'''- [[Renal tubular acidosis]], [[renal failure]] (early)
* '''H'''- [[Hyperalimentation]]
* '''A'''- [[Addison's disease]], [[acetazolamide]], [[ammonium chloride]]
* '''M'''- Miscellaneous: [[congenital chloride diarrhea]], [[amphotericin B]], [[toluene]], [[cholestyramine]],  post[[hypocapnea]]


* '''R'''- [[Renal tubular acidosis]]
====High Anion Gap Metabolic Acidosis====
The mnemonic "MUDPILES" is used to remember the common causes of a high anion gap.


* '''H'''- [[Hyperailmentation]]
* '''M''' - [[Methanol]]/ [[Metformin]]<br />
* '''U''' - [[Uremia]]<br />
* '''D''' - [[Diabetic ketoacidosis]]<br />
* '''P''' - [[Paraldehyde]]/ [[Propylene glycol]]<br />
* '''I''' - [[Infection]]/ [[Ischemia]]/ [[Isoniazid]]<br />
* '''L''' - [[Lactic acidosis]]<br />
* '''E''' - [[Ethylene glycol]]/ [[Ethanol]]<br />
* '''S''' - [[Salicylates]]/ [[Starvation]]


* '''A'''- [[Addison's disease]], [[acetazolamide]], [[ammonium chloride]]
==Management==
===Step 1===
{{familytree/start}}
{{familytree | | | | | | | | | | | A01 | | | | | |A01='''[[pH]]<7.35''' <br> And <br> ['''HCO3<sup>-</sup>]<24 meq/L'''}}
{{familytree | | | | | | | | | | | |!| | | | | | | | }}
{{familytree | | | | | | | | | | | B01 | | | | | |B01='''[[Metabolic acidosis]]'''}}
{{familytree | | | | | | | | | | | |!| | | | | | | | }}
{{familytree | | | | | | | | | | | B02 | | | | | |B02='''Calculate the [[anion gap]] (AG)''' <br><br> Na<sup>+</sup> - Cl<sup>-</sup> - HCO3<sup>-</sup>}}
{{familytree | | | |,|-|-|-|-|-|-|-|+|-|-|-|-|-|-|-|-|.| }}
{{familytree | | | C01 | | | | | | C02 | | | | | | | C03 |C01='''Low AG'''<br> AG<8|C02= '''Normal AG''' <br> 8<AG<16 |C03= '''High AG''' <br> AG>16 }}
{{familytree | |,|-|^|-|.| | | | | |!| | | | | | | | |!| }}
{{familytree | D01 | | D02 | | | | |!| | | | | | | | |!| | |D01='''Check [[albumin]]'''<br><br>Correct the AG if albumin is low<br>For every decrease of 1 g/dl of albumin, AG is decreased by 2.5 meg/L|D02='''Check Ca<sup>2+</sup>, Mg<sup>2+</sup>, K<sup>+</sup>, [[immunoglobulins]]'''<br><br> High levels of these unmeasured cations decrease the AG}}
{{familytree | | | | | | | | | | | E01 | | | | | | | E02 |~|~| E03 |E01='''Check urine AG'''<br>Na<sup>+</sup> + K<sup>+</sup> - Cl<sup>-</sup>|E02='''Check ΔAG/ΔHCO3<sup>-</sup>'''|E03= R/O low Ca<sup>2+</sup>, Mg<sup>2+</sup>, K<sup>+</sup>}}
{{familytree | | | | | | | | |,|-|-|^|-|-|.| | | |,|-|^|-|v|-|-|-|.| | }}
{{familytree | | | | | | | | F01 | | | | F02 | | F03 | | F04 | | F05 |F01='''Negative urine AG'''<br><br> [[GI]] causes<br>[[RTA|RTA type II]]|F02='''Positive urine AG'''<br><br> [[Renal failure]] <br> [[RTA|RTA type I]] <br> [[RTA|RTA type IV]] |F03=Δ'''AG/ΔHCO3<sup>-</sup><1'''<br><br>High AG metabolic acidosis combined with normal AG metabolic acidosis|F04= '''1<ΔAG/ΔHCO3<sup>-</sup><2'''<br><br> Pure high AG metabolic acidosis|F05='''ΔAG/ΔHCO3<sup>-</sup>>2'''<br><br> High AG metabolic acidosis combined with [[metabolic alkalosis]]}}
{{familytree/end}}


* '''M'''- Miscellaneous ([[chloridorrhea]], [[amphotericin B]], [[toluene]] - toluene causes high anion gap metabolic acidosis followed by normal anion gap metabolic acidosis
===Step 2===
Shown below is the algorithm summarizing the management of metabolic acidosis


====Increased/High Anion Gap Metabolic Acidosis====
{{familytree/start}}
The mnemonic "MUDPILES" is used to remember the causes of a high anion gap.
{{familytree | | | | | | | | | A01 | | | | | |A01='''History, symptoms and physical examination'''<br>Blood [[pH]] < 7.35}}
{{familytree | | | | | | | | | |!| | | | | | | | }}
{{familytree | | |,|-|-|-|-|-|-|+|-|-|-|-|-|-|.| }}
{{familytree | | C01 | | | | | C02 | | | | | C03 |C01='''Physical examination'''<br>[[Eyes]]<br>[[Extremities]]<br>Neurologic ([[cranial nerves]])|C02=Labs/[[EKG]]<br>[[Anion gap]], [[arterial blood gas|Arterial blood gas analysis]]<br>Electrolytes (Na, K, Cl, HCO3)<br>[[CBC]]<br>Serum [[lactate]], [[ketone]]<br>[[Urinalysis]]<br>Toxicological screening (salicylate, methanol, ethylene glycol)<br>[[EKG]] for arrhythmias|C03='''History'''<br>[[Arrhythmias]]<br>[[Kussmaul breathing]]<br>[[Headache]], [[altered mental status]]}}
{{familytree | | | | | | | | | |!| | | | | | | | }}
{{familytree | |,|-|-|-|v|-|-|-|+|-|-|-|v|-|-|-|.| | }}
{{familytree | |!| | | |!| | | |!| | | |!| | | |!| | | }}
{{familytree | D01 | | D02 | | D03 | | D04 | | D05 |D01=Place patient on EKG monitor for arrhythmias, hyperkalemia|D02=Replace electrolytes if there are losses|D03=If [[DKA]], IV Insulin, normal saline<br>Potassium and phosphate may be necessary|D04=Send consult to nephrologist for [[dialysis]] for [[renal failure]], [[poisoning]]|D05=Toxicological consult}}
{{familytree | |!| | | | | | | | | | | | | | | |!| }}
{{familytree | E01 | | | | | | | | | | | | | | E02 |E01=IV bicarbonate if there is cardiac arrhythmias<br>50-100mmol while monitoring arterial blood gas readings|E02=Detoxification agents/toxin antidotes<br>[[Fomepizole]]<br>[[Activated charcoal]]<br>[[Emesis]]<br>[[Folic acid]] for methanol overdose<br>[[Thiamine]] and [[pyridoxine]] for ethylene glycol overdose}}
{{familytree/end}}


'''M''' - [[Methanol]]/[[Metformin]]<br />
==Do's==
'''U''' - [[Uremia]]<br />
*Treatment of the underlying cause should be the primary therapeutic goal.
'''D''' - [[Diabetic ketoacidosis]]<br />
*Bicarbonate should be given only when there is a severe case of acidosis with an arterial [[pH]] of less than or equal to 7.2
'''P''' - [[Paraldehyde]]/[[Propylene glycol]]<br />
*Patient should be placed on SaO2 and [[blood pressure]]/[[heart rate]] monitor
'''I''' - [[Infection]]/[[Ischemia]]/[[Isoniazid]]<br />
*Consider intubation and ventilation for airway if the SaO2 level is deteriorating or there is a loss of consciousness
'''L''' - [[Lactate]]<br />
*Consider doing catherization to monitor the urine output and obtaining urine for urinalysis
'''E''' - [[Ethylene glycol]]/[[Ethanol]]<br />
'''S''' - [[Salicylates]]/[[Starvation]]


==Management==
==Dont's==
* Do not administer [[vasoconstrictors]] in the presence of [[lactic acidosis]]


==References==
{{Reflist|2}}


==Do's and Dont's==
[[Category:Electrolyte disturbance]]
[[Category:Emergency medicine]]
[[Category:Intensive care medicine]]
[[Category:Laboratory Test]]
[[Category:Medical tests]]
[[Category:Medicine]]
[[Category:Nephrology]]
[[Category:Resident survival guide]]


==References==
{{WH}}
{{Reflist|2}}
{{WS}}

Latest revision as of 22:58, 20 October 2014

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Ogheneochuko Ajari, MB.BS, MS [2]

Overview

Metabolic acidosis is a state in which the blood pH is low (less than 7.35) due to a decreased blood concentration of bicarbonate.

Causes

Life Threatening Causes

Common Causes

Normal Anion Gap Metabolic Acidosis

The mnemonic for the most common causes of a normal-anion gap metabolic acidosis is "DURHAM."

High Anion Gap Metabolic Acidosis

The mnemonic "MUDPILES" is used to remember the common causes of a high anion gap.

Management

Step 1

 
 
 
 
 
 
 
 
 
 
pH<7.35
And
[HCO3-]<24 meq/L
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Metabolic acidosis
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Calculate the anion gap (AG)

Na+ - Cl- - HCO3-
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Low AG
AG<8
 
 
 
 
 
Normal AG
8<AG<16
 
 
 
 
 
 
High AG
AG>16
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Check albumin

Correct the AG if albumin is low
For every decrease of 1 g/dl of albumin, AG is decreased by 2.5 meg/L
 
Check Ca2+, Mg2+, K+, immunoglobulins

High levels of these unmeasured cations decrease the AG
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Check urine AG
Na+ + K+ - Cl-
 
 
 
 
 
 
Check ΔAG/ΔHCO3-
 
 
R/O low Ca2+, Mg2+, K+
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Negative urine AG

GI causes
RTA type II
 
 
 
Positive urine AG

Renal failure
RTA type I
RTA type IV
 
ΔAG/ΔHCO3-<1

High AG metabolic acidosis combined with normal AG metabolic acidosis
 
1<ΔAG/ΔHCO3-<2

Pure high AG metabolic acidosis
 
ΔAG/ΔHCO3->2

High AG metabolic acidosis combined with metabolic alkalosis

Step 2

Shown below is the algorithm summarizing the management of metabolic acidosis

 
 
 
 
 
 
 
 
History, symptoms and physical examination
Blood pH < 7.35
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Physical examination
Eyes
Extremities
Neurologic (cranial nerves)
 
 
 
 
Labs/EKG
Anion gap, Arterial blood gas analysis
Electrolytes (Na, K, Cl, HCO3)
CBC
Serum lactate, ketone
Urinalysis
Toxicological screening (salicylate, methanol, ethylene glycol)
EKG for arrhythmias
 
 
 
 
History
Arrhythmias
Kussmaul breathing
Headache, altered mental status
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Place patient on EKG monitor for arrhythmias, hyperkalemia
 
Replace electrolytes if there are losses
 
If DKA, IV Insulin, normal saline
Potassium and phosphate may be necessary
 
Send consult to nephrologist for dialysis for renal failure, poisoning
 
Toxicological consult
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
IV bicarbonate if there is cardiac arrhythmias
50-100mmol while monitoring arterial blood gas readings
 
 
 
 
 
 
 
 
 
 
 
 
 
Detoxification agents/toxin antidotes
Fomepizole
Activated charcoal
Emesis
Folic acid for methanol overdose
Thiamine and pyridoxine for ethylene glycol overdose

Do's

  • Treatment of the underlying cause should be the primary therapeutic goal.
  • Bicarbonate should be given only when there is a severe case of acidosis with an arterial pH of less than or equal to 7.2
  • Patient should be placed on SaO2 and blood pressure/heart rate monitor
  • Consider intubation and ventilation for airway if the SaO2 level is deteriorating or there is a loss of consciousness
  • Consider doing catherization to monitor the urine output and obtaining urine for urinalysis

Dont's

References

Template:WH Template:WS