Schwarz-Barter syndrome: causes, symptoms, diagnosis, treatment

Syndrome Schwartz - Barter - a syndrome of inadequate secretion of antidiuretic hormone. Clinical symptoms depend on the degree of water intoxication and the degree of hyponatremia. The main signs of this disease are hyponatremia, a decrease in the osmotic pressure of blood plasma and other body fluids with a simultaneous increase in the osmotic pressure of urine. Despite the fact that the water content in the body increases, such symptoms as edema and hypertension are absent (the presence of edematous syndrome is possible with a significant increase in water intake only with a simultaneous kidney disease with a violation of sodium secretion or heart failure).

The causes of the Schwartz-Barter syndrome

Syndrome Schwartz-Barter often proceeds subclinically, is rare, but even less likely to be diagnosed, can accompany numerous CNS diseases (both diffuse and local). A laboratory study of the sodium level in the blood can make the right diagnosis and take the necessary measures. Various reasons leading to the syndrome of inadequate secretion of antidiuretic hormone are explained by the fact that the predominant inhibitory effect of the secretion of antidiuretic hormone is carried out by the supragippothalamic formations. Thus, with diseases of the central nervous system of different nature and localization, a kind of "denervation" hyperactivation of hypothalamic-pituitary structures may occur, followed by hypersecretion of antidiuretic hormone. In some cases, the causes of the disease can not be established, then the idiopathic syndrome of inadequate secretion of the antidiuretic hormone is diagnosed.

Pathogenesis of Schwartz-Barter syndrome

As a result of hypersecretion of antidiuretic hormone, fluid accumulation and a progressive decrease in the concentration of substances dissolved in the body occur.

With an increase in water volume by 10%, urinary sodium excretion increases. The sodium syrup cuts the hypervolemia somewhat, but increases hyponatraemia, while the lowering of the osmotic pressure of the body's liquid media even more progresses. Hyper secretion of antidiuretic hormone is associated with hyperactivation of supraoptic nuclei of hypothalamus and neurohypophysis, which, as a rule, develops as a result of violation of extrahypothalamic inhibitory mechanisms with respect to antidiuretic hormone.

The degree of severity is divided into mild, or chronic, form, moderate and severe, depending on the severity of hyponatremia. For mild, or chronic, forms are characterized by complaints of decreased appetite, fatigue, nausea. Most often this form is subclinical. In severe cases, with a decrease in the concentration of sodium to 120 meq / l, vomiting, drowsiness, confusion occur. With a further decrease in the sodium concentration to 100 meq / l and lower, paresis, convulsions, and coma may occur. These brain phenomena are caused by the development of hyperhydration and symptoms of cerebral edema. It should be emphasized that the clinical manifestations of the disease directly depend on the amount of fluid consumed.

Differential diagnosis. It should be performed with ectopically located tumors secreting antidiuretic hormone (bronchogenic cancer, thymoma, pancreatic cancer, ureter cancer, duodenal cancer, Ewing's sarcoma), non-tumor lung diseases (pneumonia, fungal diseases, tuberculosis), drug intoxication (vasopressin, oxytocin , vincristine, chlorpropamide, chlorothiazide, tegretol, nicotine, phenothiazines, cyclophosphamide), endocrinopathies (myxedema, Addison's disease, hypopituitarism), somatic diseases erdechnaya failure, cirrhosis of the liver).

Treatment of Schwartz-Barter syndrome

The main therapeutic tactic is a rigid restriction of fluid intake. Its total consumption should not exceed 0.5 l / day. In urgent conditions with cerebral symptoms, infusion of hypertonic sodium chloride solution (3-5%) is administered, which is administered at a rate of 3 ml / kg per hour with simultaneous intravenous administration of furosemide. With mild and mild forms, furosemide is not used because of severe natriouria. Effective drugs are oppressive to vasopressin on the kidneys, such as demeclocycline (dexlomycin). It is prescribed for a chronic form of the syndrome in a dose of 1.2 g / day. When it is used, it is possible to cause a reversible form of nephrogenic diabetes insipidus. The use of lithium carbonate for the same purpose is hardly justifiable, since it has high toxicity and pronounced side effects.