A. Metabolic Acidosis

1. Elevated anion gap (Mnemonic = "MUD PILES")
   1. Methanol
   2. Uremia (renal failure)
   3. Diabetic Ketoacidosis
   4. Paraldehyde
   5. Infection
   6. Lactic Acidosis (Ischemia, Infection)
   7. Ethylene Glycol
   8. Salicylates
2. Chronic renal failure
   1. Reduced acid excretion
   2. Reduced HCO3- resorption by the kidney
   3. Initial normal anion gap (tubular acidosis) then increased anion gap as acids accumulate
   4. Hyperchloremia and hypersulfatemia
   5. Initial Na+ retention with fluid leads to hypertension, then Na+ losses
3. Hyperchloremic (normal anion gap)
   1. Renal Dysfunction
   2. Loss of Alkali
   3. When Urine Anion Gap is positive (UNa+UK-UCl > 0), then kidney dysfunction is cause
   4. Otherwise, kidney is not the cause
4. Renal tubular dysfunction
   1. Renal tubular acidosis
   2. Hypoaldosteronism (Addison's Disease)
   3. K+ sparing diuretics (especially spironolactone)
5. Loss of Alkali
   1. Strong Ion Difference decreased
   2. Pancreatitis
   3. Diarrhea
   4. Carbonic anhydrase inhibitor (Acetazolamide)
   5. Ammonium chloride and cationic amino acids
6. Hyperproteinemia (elevated anion gap): with low HCO3-

B. Respiratory Acidosis

1. COPD with carbon dioxide (CO2) retention
2. Restrictive Disease, endstage
3. Bradypnea
4. Increased work of breathing with subsequent fatigue: eg. acute asthma attack