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Test Findings


April 24th, 2019


Hyperchloraemia rarely exists on its own, and is usually found in the presence of hypernatraemia (due to water loss or salt gain) or normal anion gap (hyperchloraemic) metabolic acidosis. Hyperchloraemia can also occur in the setting of renal compensation for respiratory alkalosis.


  • Causes of Hyperchloraemia

  • Water Loss

  • Inadequate water intake
  • Diabetes insipidus (neurogenic / nephrogenic)
  • Loop diuretics
  • Acute tubular necrosis (polyuric phase)
  • Osmotic diuresis (e.g. poorly controlled diabetes)
  • Non-urinary loss - insensible, sweat, burns, diarrhoea
  • Salt Gain

  • Excessive administration - dietary excess, hypertonic saline, hypertonic dialysis
  • Hyperaldosteronism
  • Cushings
  • Hyperchloraemic Metabolic Acidosis

  • GI loss - diarrhoea, fistula, stoma
  • Isotonic saline infusion
  • Renal tubular acidosis
  • Acetazolamide
  • Addison's disease
  • Compensation for Respiratory Alkalosis

  • Hyperventilation - hypoxia, anxiety, pain, intracranial pathology, pregnancy


Determine whether the patient is hypernatraemic or has an acid-base abnormality, and then investigate further depending on the result.
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