METABOLIC ACIDOSIS

• With increased anion gap: lactic acidosis, ketoacidosis, poisoning & overdose (e.g., paraldehyde, ethylene glycol, methanol, aspirin)
• With normal anion gap: diarrhea, renal tubular acidosis, interstitial nephritis, excess NH₄Cl administration, drainage from a ureterosigmoidostomy, acetazolamide administration

METABOLIC ALKALOSIS

• Chloride-responsive (responds to NaCl or KCl): contraction alkalosis; diuretics; corticosteroids; gastric suctioning; vomiting
• Chloride-resistant: any hyperaldosterone state, e.g., Cushing's syndrome; Bartter's syndrome; severe K⁺ depletion

RESPIRATORY ACIDOSIS

• Central nervous system depression, e.g., drug overdose, anesthesia
• Chest bellows weakness or dysfunction, e.g., myasthenia gravis, polio, massive obesity, diaphragm paralysis, flail chest, paralyzing agents
• Disease of lungs and/or upper airway, e.g., severe asthma attack, chronic obstructive pulmonary disease, severe pneumonia, severe pulmonary edema, upper airway obstruction

RESPIRATORY ALKALOSIS

• Voluntary hyperventilation
• Hypoxemia (includes altitude)
• Liver failure
• Anxiety hyperventilation syndrome
• Sepsis
• Any acute pulmonary problem, e.g., acute pulmonary embolism, pneumonia, mild asthma attack, mild pulmonary edema