Fluids, Electrolytes, Acid-Base Disorders, and Nutrition Support
| d. | Causes of an AG acidosis: One easy pneumonic to remember (there are others) is MUDPILES: |
|---|
M = Methanol
U = Uremia (including rhabdomyolysis)
D = Diabetes (diabetic ketoacidosis [DKA]*) *Incidence of euglycemic DKA has grown with
increase in use of sodium-glucose transporter 2 inhibitors.
P = Paraldehyde, propylene glycol
I = Isoniazid or iron
L = Lactic acidosis
E = Ethylene glycol or ethanol toxicity
S = Salicylates
Types of lactic acidosis (lactate greater than 4 mmol/L and pH less than 7.35)
Type A: Hypoperfusion (cardiogenic or septic shock, regional ischemia, severe anemia)
ii.
Type B: Metabolic β No tissue hypoxia
| (a) | B1 = underlying disease (diabetes, liver disease, leukemia, lymphoma, AIDS) |
|---|---|
| (b) | B2 = drugs/toxins (metformin, didanosine/stavudine/zidovudine, ethanol, linezolid, |
propofol, propylene glycol toxicity caused by intravenous lorazepam or pentobarbital),
nitroprusside (cyanide) toxicity
| (c) | B3 = inborn errors of metabolism (pyruvate dehydrogenase deficiency) |
|---|
Causes of a normal AG acidosis
Another easy pneumonic to remember (there are others) is ACCRUED.
A = Ammonium chloride/acetazolamide (urine bicarbonate loss)
C = Chloride intake (PN, intravenous solutions)
C = Cholestyramine (GI bicarbonate loss)
R = Renal tubular acidosis: Types I, II, and IV
U = Urine diverted into the intestine (e.g., ileal conduit, vesicoenteric fistula)
E = Endocrine disorders (e.g., aldosterone deficiency)
D = Diarrhea or small/large bowel fluid losses (e.g., enterocutaneous fistulas)
disorders
Delta ratio =
ΞAG/ΞHCO3 = (measured AG β normal AG)/(normal HCO3 β measured HCO3) =
(AGβ14)/(24 β measured HCO3)
Delta Ratio
Assessment
< 0.4
Hyperchloremic normal AG acidosis
< 1
Mixed high AG acidosis and hyperchloremic normal AG acidosis
1β2
AG acidosis (no hidden process)
> 2
High AG acidosis and concurrent metabolic alkalosis OR a preexisting compensated
respiratory alkalosis
aThe ratio should be used cautiously in interpreting mixed acid-base disorders, given that it is associated with poor sensitivity because of several influencing factors (J
Am Soc Nephrol 2007;18:2429-31). This author prefers to look at current clinical state/diagnoses and recent therapeutic interventions for the patient to ascertain whether
a mixed acid-base disorder is potentially present.