Gitelman’s syndrome, first reported in three patients in 1966, is an autosomal recessive renal tubular disease characterized by hypokalemia, hypochlorhydria, and normotension, often accompanied by hypocalcemia and hypomagnesemia. Etiology and pathogenesis Gitelman syndrome is caused by hypofunction of the Na/Cl cotransporter on the distal tubule. cDNA for the Na/Cl cotransporter (NKCC) has been cloned at 16q13, and patients with Gitelman syndrome have a mutation in the gene encoding NKCC. In other words, defects in the Na+/Cl- cotransporter system in the cortical part of the distal tubule underlie the pathogenesis of GS. impaired reabsorption of Na+ and Cl- leads to a mild circulating blood volume deficit, which stimulates the renin-angiotensin-aldosterone system, resulting in enhanced reabsorption of Na+ and water by the principal cells in the medullary part of the distal tubule, a process that expels K+; secretion of H+ and absorption of Cl- The impaired secretion of H+ and absorption of Cl- become the cause of metabolic alkalosis. The causes of urinary calcium depression and hypomagnesemia are not fully understood. Some scholars believe that it is related to the high absorption of Ca++ in the distal tubule, which is due to: (1) the reduction of Na+ reabsorption activates the basal cell membrane Na+2 Ca++ pump (which drains intracellular Ca++ into the blood vessels and absorbs Na+ into the cells), which in turn leads to the opening of apical cell membrane calcium channels and increases the reabsorption of Ca++ in primary urine. (2) Decreased reabsorption of Cl – decreases the intracellular Cl – level, increasing the polarization of the apical cell membrane and stimulating the uptake of Ca + + into the cell. It has also been suggested that a mild decrease in extracellular fluid increases Ca + + reabsorption in the proximal tubule. As for the cause of hypomagnesemia in GS patients, some authors suggest that it is related to reduced magnesium reabsorption in the distal tubule by an unclear mechanism . Similarly, defects in the Na + / Cl – cotransport system result from alterations in its encoding membrane genes. Clinical manifestations The electrolyte disturbances caused by Gitelman syndrome are characterized by hypokalemia, hyponatremia, and hypovolemia, similar to the adverse effects caused by thiazide diuretics, and can be followed by increased renin and angiotensin, insignificant or normal aldosterone elevation, and hypocalcemia and hypomagnesemia. However, the clinical manifestations of the disease can be intricate and complex, and the clinical phenotype is highly variable, often with onset in adolescents or adults. Infants and children are often seen for growth retardation and convulsions, while some patients can have no signs or symptoms, often with biochemical abnormalities as the first manifestation. Some of them show easy fatigue, muscle weakness, episodic weakness and hand-foot convulsions, often accompanied by abdominal pain, vomiting and fever during seizures. The asymptomatic period can be long, so some cases are diagnosed in adults, and polyuria and growth retardation are not obvious. Diagnosis The diagnosis of Gitelman syndrome can be made in this case by combining history and treatment. The disease needs to be differentiated from Bartter’s syndrome and renal tubular acidosis. Treatment A lifelong magnesium dose is required. Mostly magnesium chloride is used to partially correct hypomagnesemia to prevent convulsions; and to replace the loss of chloride. Sometimes need to give potassium salts and anti-aldosterone drugs such as anisodone.