Hypochloremia: Description, Causes and Risk Factors:
Hypochloremia is a serum chloride level below 95 mEq/L. Normal serum chloride level is 101 to 112 mEq/L. Chloride is the major anion in the extracellular fluid (ECF). The intracellular level of chloride is only about 2 to 4 mEq/L. Chloride is regulated in the body primarily through its relationship with sodium. Serum levels of both sodium and chloride often parallel each other.
A main function of chloride in the body is to join with hydrogen to form hydrochloric acid (HCl). HCl aids in digestion and activates enzymes, such as salivary amylase. Chloride plays a role in maintaining the serum osmolarity and body water balance. The normal serum osmolarity ranges between 280 and 295 mOsm/L.
Chloride deficit leads to a number of physiological alterations such as ECF volume contraction, potassium depletion, intracellular acidosis, and increased bicarbonate generation. Hypochloremia, similar to hyponatremia, also causes a decrease in the serum osmolarity. This decrease means that there is a decrease in sodium and chloride ions in proportion to water in the ECF. When there is a body water excess, chloride also may be decreased along with sodium, preventing reabsorption of body water by the kidneys.
Chloride control depends on the intake of chloride and the excretion andreabsorption of its ions in the kidneys. Chloride is produced in the stomach ashydrochloric acid; a small amount of chloride is lost in the feces. Chloride-deficientformulas, salt restricted diets, GI tube drainage, and severe vomiting and diarrheaare risk factors for hypochloremia. As chloride decreases(Usually because of volume depletion), sodium and bicarbonate ions are retained bythe kidney to balance the loss. Bicarbonate accumulates in the ECF, which raisesthe pH and leads to hypochloremic metabolic alkalosis.
The most common cause of hypochloremia is gastrointestinal (GI) abnormalities, including prolonged vomiting, nasogastric suctioning, loss of potassium, and diarrhea. Loss of potassium, which occurs as a result of gastric suctioning and vomiting, further leads to hypochloremia because potassium frequently combines with chloride to form potassium chloride (KCl). Chloride is also lost through diarrhea, which has a high chloride content.
Other causes of hypochloremia are dietary changes, renal abnormalities, acid-base imbalances (particularly respiratory acidosis and metabolic alkalosis), and skin losses. Diets low in sodium can contribute to hypochloremia, as can medications such as thiazide and loop diuretics. Another common cause in hospitalized patients is the combination of stopping all oral intake during an illness and placing patients on intravenous (IV) fluid.
Several genetic diseases can result in low blood chloride levels. These include cystic fibrosis. Bartter's syndrome is a group of several disorders of impaired salt reabsorption in the thick ascending loop of Henle: hypochloremia, hypokalemic metabolic alkalosis, and hypercalciuria. Several genes have been associated with Bartter's syndrome (bumetanide-sensitive Na-K-2Cl cotransporter SLC12A1, the BSND gene, simultaneous mutation in both the CLCNKA and the CLCNKB genes and the thiazide-sensitive sodium-chloride cotransporter SLC12A3). Congenital adrenal hyperplasia is a heritable disorder of adrenal corticosteroid synthesis that is transmitted in autosomal recessive disorder; it too can result in hypochloremia.
Risk Factor: Addison's disease, reduced chloride intake or absorption untreateddiabetic ketoacidosis, chronic respiratory acidosis, excessive sweating, vomiting, gastricsuction, diarrhea, sodium and potassium deficiency, metabolic alkalosis, loop, osmotic, or thiazide diuretic use, overuse of bicarbonate, rapid removal of ascetic fluid with a high sodiumcontent, intravenous fluids that lack chloride (dextrose and water), draining fistulas andileostomies, heart failure, cystic fibrosis.
- Muscle cramps.
- Hyperactive deeptendon reflexes.
- Shallow respirations.
The normal serum chloride level is 96 to 106 mEq/L(96-106 mmol/L). Inside the cell,the chloride level is 4 mEq/L. In addition to the chloride level, sodium and potassiumlevels are also evaluated because these electrolytes are lost along with chloride.Arterial blood gas analysis identifies the acid-base imbalance, which is usuallymetabolic alkalosis. The urine chloride level, which is also measured, decreases inhypochloremia.
Treatment involves correcting the cause of hypochloremia and contributing electrolyte and acid-base imbalances. Normal saline (0.9% sodium chloride) or half-strength saline (0.45% sodium chloride) solution is administered IV to replace the chloride. The physician may reevaluate whether patients receiving diuretics (loop, osmotic, or thiazide) should discontinue these medications or change to another diuretic. Foods high in chloride are provided; these include tomato juice, salty broth, canned vegetables, processed meats, and fruits. A patient who drinks free water (water without electrolytes) or bottled water will excrete large amounts of chloride; therefore, this kind of water should be avoided. Ammonium chloride, an acidifying agent, may be prescribed to treat metabolic alkalosis; the dosage depends on the patient's weight and serum chloride level. This agent is metabolized by the liver, and its effects last for about 3 days.
NOTE: The above information is for processing purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.