Urine Cl < 20 mEq/L
Vomiting
NG suction
Bulimia
Diarrhea
Congenital chloridorrhea
Villous adenoma
Urine Cl > 20 mEq/L
Exogenous alkali (Nabicarb + renal failure,<unk> m of lactic acid, or ketoacids)
Potassium acetate
Milk alkali syndrome
Hypercalcemia (inability to concentrate urine leads to hypovolemia)
Intravenous penicillin
Refeeding<unk> 
Massive blood transfusion
Primary hyperaldosteronism
CAH (11-Hydroxylase or 17-hydroxylase deficiency)
Cushing syndrome
Exogenous steroids
Liddle syndrome
Renovascular hypertension
Bartter syndrome (pediatrics)
Gitelman syndrome (pediatrics)
Severe K+ depletion
Hypomagnesemia
Potassium acetate
Metabolic alkalosis
Urine Cl < 20 mEq/L
Metabolic acidosis
Vomiting
Anion gap acidosis
NG suction
Hypercapnia
Bulimia