A low serum chloride level occurs when intake decreases through a low-salt diet. It also may occur with continuous administration of intravenous fluids without chloride, such as dextrose
in water. In rare situations it may occur due to an extreme intake of free water.

An increase in chloride loss contributes to hypochloremia. Chloride is lost through the renal and gastrointestinal systems and through the skin with excessive sweating. Draining fistulas, ileostomies, or prolonged nasogastric suctioning without replacement of chloride can cause a hypochloremic state. Excessive vomiting and diarrhea are situations also related to chloride loss. When hydrochloric acid is lost from the stomach, a situation of metabolic alkalosis can occur due to the fact that there is less competition for the bicarbonate ion with sodium. The loop (Lasix), osmotic (Mannitol), and thiazide (hydrochlorothiazide) diuretics may also bring about a loss of chloride through a decreased absorption of water and electrolytes in the renal system (Table 22-1). All losses contribute to decreased absorption.