Hypochloremia - Differential Diagnosis Algorithm



Cause - Decreased Intake:

 • Low salt in diet

 • Exclusive D5W use

 • Water intoxication



Cause - Increased Loss:

 • GI LOSS:

	- Excessive vomiting

	- Metabolic alkalosis

	- Fistulas

	- Ileostomy

	- NGT suction

	- Diarrhea

 • RENAL LOSS:

	- Diuresis

	- Bartter

	- Gitelman



SIGNS:

 • Muscle weakness

 • Hypotension

 • AMS (altered mental status)

 • Tachycardia

 • Fatigue



Chloride is essential for blood pressure control, decarboxylation/gas transport, renal function, and gastrointestinal homeostasis.

 • Blood pressure:

	- Cl⁻ increases blood pressure

	- Cl⁻ is inversely related to renin secretion

	- Cl⁻ influences smooth muscle cells

 • Gas exchange:

	- Transcellular shifting of Cl⁻ facilitates oxygen unloading

 • Kidney:

	- Cl⁻ is inversely related to glomerular filtration rate by tubulo-glomerular feedback mechanism

 • Gastrointestinal function

	- Cl⁻ is the major contributor to stomach acidity

	- Cl⁻ is responsible for maintenance of the gastrointestinal osmotic gradient and fluid secretion

 • Acid-base equilibrium

	- Cl⁻ is the major extracellular anion

	- Interplay of Cl⁻ with other components of acid-base homeostasis is complex

	- Cl⁻ increase may cause metabolic acidosis

	- Cl⁻ decrease may cause metabolic alkalosis



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