Predisposing factors

General

• Depends on the underlying cause.

Pathophysiology

• Change in chloride concentration caused by:
  • Any gain of chloride.
  • Change in water balance (decrease in free water).  This is always associated with a proportional increase or decrease in sodium Hypernatremia  Hyponatremia.
• Chloride should be corrected for changes in sodium (changes in water balance):
   [Cl] (corrected)= [Cl](measured) x [Na] (normal) /   [Na] (measured)
• Artifactual hyperchloremia (elevated measured [Cl-], with normal corrected [Cl-]) Blood biochemistry: chloride:
  • Pure water loss:
    • Diabetes insipidus Diabetes insipidus.
    • Essential hypernatremia Hypernatremia.
    • Increased ambient temperature.
    • Primary hypodipsia.
    • Fever.
    • Inadequate access to water.
  • Hypotonic fluid loss:
    • Osmotic diuresis.
    • Gastrointestinal (vomiting, diarrhea, intestinal obstruction).
    • Renal (osmotic diuresis, chronic renal failure, acute renal failure, post-obstructive diuresis).
    • Third spacing.
    • Cutaneous losses.
• Corrected hyperchloremia (associated with hyperchloremic [normal AG] metabolic acidosis Acid base imbalance):
  • Pseudo hyperchloremia:
    • Lipemic sample (evaluated with colorimetric technique).
    • Therapy with potassium bromide Potassium bromide (bromide is measured as chloride in every chloride assay).
  • Excessive loss of sodium relative to chloride:
    • Diarrhea associated with gastrointestinal loss of sodium rich/chloride poor fluid.
  • Renal chloride retention:
    • Diarrhea.
    • Renal failure Kidney: chronic kidney disease Kidney: acute renal failure.
    • Type I renal tubular acidosis (renal tubular disorders that cause renal wasting of bicarbonate or low hydrogen ion secretion).
    • Diabetes mellitus Diabetes mellitus (in the initial or resolving phase when ketones are eliminated in urine as fast as they are generated: excretion of ketones in the urine in place of chloride).
    • Chronic respiratory alkalosis.
    • Drug induced (spironolactone Spironolactone inhibits sodium reabsorption and increase chloride retention; acetazolamide Acetazolamide).
  • Excessive gain of chloride relative to sodium:
    • Fluid therapy Fluid therapy: overview (0.9% NaCl, hypertonic saline, KCl supplemented fluid).
    • Therapy with chloride salt (eg Ammonium chloride Ammonium chloride).
    • Total parenteral nutrition.
    • Salt poisoning.