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Metabolic Acidosis
Aka: Metabolic Acidosis, Non-Anion Gap Metabolic Acidosis, Anion Gap Metabolic Acidosis
- See Also
- Arterial Blood Gas
- ABG Interpretation
- Types
- Elevated Anion Gap Metabolic Acidosis
- Hyperchloremic Metabolic Acidosis (normal Anion Gap)
- See Hyperchloremia
- Causes: Elevated Anion Gap (Mnemonic: "MUD PILERS")
- Methanol
- Uremia
- Diabetic Ketoacidosis (DKA) or starvation ketosis
- Paraldehyde, Phenformin
- Isopropyl Alcohol, Isoniazid
- Lactic Acidosis
- Ethylene Glycol, Ethyl Alcohol
- Rhabdomyolysis
- Salicylates
- Other Causes: Hyperalbuminemia, administered anions
- Causes: Normal Anion Gap (Hyperchloremia)
- Hypokalemia with Metabolic Acidosis
- Diarrhea
- Ureteral diversion
- Uretero-sigmoidostomy
- Ileal Bladder
- Ileal ureter
- Renal Tubular Acidosis (proximal or distal)
- Mineralocorticoid Deficiency
- Angiotensin Deficiency: Liver Failure
- ACE Inhibitor
- Renin Deficiency
- Aging
- Extracellular fluid volume expansion
- Lead
- Beta Blockers
- Prostaglandin Inhibitor
- Methyldopa
- Carbonic anhydrase inhibitor
- Acetazolamide
- Mefenamic acid
- Post-hypocapnia
- Hyperkalemia (or normal potassium) Metabolic Acidosis
- Renal Failure (Early)
- Renal Disease
- SLE Interstitial Nephritis
- Amyloidosis
- Hydronephrosis
- Sickle Cell Nephropathy
- Acidifying agents
- Ammonium Chloride
- Calcium Chloride
- Arginine
- Sulfur toxicity
- Labs
- Arterial Blood Gas
- Arterial pH decreased
- Serum bicarbonate decreased
- PaCO2 decreased
- PaCO2 drops 1.2 mmHg per 1 meq/L bicarbonate fall
- Calculated PaCO2 = 1.5 x HCO3 + 8 (+/- 2)
- Useful in High Anion Gap Metabolic Acidosis
- Measured PaCO2 discrepancy: respiratory disorder
- Serum Chemistry panel
- Anion Gap
- Increased in high Anion Gap Metabolic Acidosis
- Excess Anion Gap <23 mEq/L
- Suggests Non-Anion Gap Metabolic Acidosis
- Serum Potassium
- Investigate normal Anion Gap Metabolic Acidosis
- See above
- Serum Chloride
- Elevated in normal Anion Gap Metabolic Acidosis
- Serum bicarbonate
- Decreased in increased Anion Gap Metabolic Acidosis
- Bicarbonate decrease matches Anion Gap increase
- Urinalysis with Urine pH
- Urine pH >6: Suggests Renal cause
- Urine pH <6: Suggests Gastrointestinal cause
- Urine Anion Gap (obtain urine electrolytes)
- Decreased Urine Anion Gap <-10
- Extrarenal Non-Anion Gap Metabolic Acidosis
- Increased Urine Anion Gap >+10
- Renal Non-Anion Gap Metabolic Acidosis
- References
- Arieff (1993) J Crit Illn 8(2): 224-46
- Narins (1982) Am J Med 72:496
- Narins (1980) Medicine 59:161-95
- Ghosh (2000) Fed Pract p. 23-33
- Rutecki (Dec 1997) Consultant, p. 3067-74
- Rutecki (Jan 1998) Consultant, p. 131-42