Chlorides in urine

The amount of chlorine in the urine depends on its content in the food. In infants with urine, very little chlorine is excreted, since its content in breast milk is low. The transition to mixed nutrition leads to a significant increase in the content of chlorine in the urine. The amount of chlorine in the urine increases in accordance with the increasing use of table salt. Approximately 90% of food chlorides are excreted in urine and only 6% - with sweat.

Reference values (norm) of urinary excreted chlorine

Age	The amount of chlorine, meq / day (mmol / day)
Children under 1 year old Children Subsequently	2-10 15-40 110-250

Determination of the content of chlorine in the urine is of great diagnostic value in resuscitation patients in severe condition. This study has particular importance for establishing the causes of metabolic alkalosis and the possibility of its correction by the introduction of chlorine. There are the following types of metabolic alkalosis.

• Chloride-sensitive alkalosis with a concentration of chloride in the urine below 10 mmol / l is the most common form of metabolic alkalosis, usually it is accompanied by a decrease in the volume of extracellular fluid. It can occur with the loss of chlorine through the digestive tract (vomiting, aspiration of the stomach contents, villous adenoma and congenital chloridorrhea) or with the use of diuretics (due to the concomitant decrease in the volume of extracellular fluid and hypokalemia). It should always be considered that the introduction of a large dose of diuretics can even increase the level of chlorine in the urine; This should be borne in mind when evaluating metabolic alkalosis and the results of the determination of chlorine in the urine. Post-hypercapnia states due to stable renal bicarbonate retardation, excessive bicarbonate administration or repeated blood transfusions (overload with citrate) may also cause a chlorine-sensitive metabolic alkalosis.
• Chloride-resistant alkalosis with a chlorine content in the urine above 20 mmol / l is observed much more rarely. Except for cases of Bartter's syndrome and magnesium deficiency in the body, with arthritic hypertension, alkalosis of this type is usually observed, and the volume of extracellular fluid is not reduced. Other causes of alkalosis of this type are primary aldosteronism, Cushing's syndrome, renal artery stenosis, Liddle syndrome, hypercalcemia, and severe hypokalemia.

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