Abstract
Hypochloremia is an electrolyte disturbance characterized by low serum concentration of chloride ions, often occurring in acute illnesses and characterized by nonspecific signs and symptoms. It rarely results from decreased intake and is predominantly due to either renal or extra-renal losses. We report a case of severely worsening symptomatic hypochloremia resulting from an extra-renal loss of chloride ion in a 58-year-old female patient presenting for prolonged protracted vomiting. Chloremia reached a surprising level of 48 mEq/L, the lowest level reported in the literature. The patient was eventually diagnosed with a rare signet ring cell carcinoma that occurred in the ampulla of Vater, leading to a malignant gastric outlet obstruction and causing extra-renal loss of chloride.