Hypernatremia

Introduction to hypernatremia Hypernatremia refers to hypernatremia (usually >145mmol / L) with high blood osmotic pressure, except in a few cases (input too much liquid containing too much sodium salt), the main problem is Loss of water, sometimes accompanied by loss of sodium, but the degree of water loss is greater than the loss of sodium. This disease often has a decrease in intracellular water. This is because extracellular extra-osmotic pressure can absorb intracellular water out of the cell; therefore, blood volume does not begin to decrease, but it can be reduced in the late stage. Found in right heart failure, nephrotic syndrome, cirrhosis, ascites and other pre-renal oliguria; acute and chronic renal failure and other renal oliguria; metabolic acidosis, cardiopulmonary resuscitation and other supplemental alkali; elderly or infant kidney function bad. Cushing's syndrome, primary aldosteronism and other potassium-sparing diseases, using deoxycorticosterone, licorice potassium and sodium-sparing drugs. basic knowledge The proportion of sickness: 0.01% Susceptible people: no specific population Mode of infection: non-infectious Complications: excessive water hyperkalemia dehydration shock

Cause of hypernatremia

Insufficient water intake (20%):

Lack of water in the voyage or desert, coma, refusal to eat, digestive tract lesions cause drinking water difficulties, brain trauma, cerebrovascular accidents, etc., causing thirst center bluntness or osmotic receptors are not sensitive, primary drinking water can cause water Insufficient intake leads to hypernatremia.

Too much water loss (30%):

(1) Loss through the kidney: a large amount of sweat caused by intense exercise in high heat and high temperature environment can cause a large loss of water from the skin; wheezing state, excessive ventilation, tracheotomy, etc. can cause excessive loss of water from the respiratory tract; Osmotic watery diarrhea can also cause this disease, and if combined with eating disorders, the situation can be seriously deteriorated.

(2) Kidney loss: mainly caused by central diabetes insipidus and renal diabetes insipidus or the application of a large number of osmotic diuretics. Renal diabetes insipidus is a disease caused by abnormal V2 receptor gene of AVP. In congenital renal diabetes insipidus, nearly 10% of patients are caused by AQP2 gene mutation. Recent studies have confirmed that many acquired renal diabetes insipidus, including lithium poisoning, hypokalemia, hypercalcemia, and obstructive nephropathy, also have AQP2 dysregulation. Uncontrolled diabetes causes a large amount of excess solute particles to pass through the renal tubules to cause osmotic diuresis; long-term nasal feeding high-protein liquid diet and other solute diuretic (called nasal feeding syndrome); use hypertonic glucose solution, mannitol, Yamanashi Dehydration therapy such as alcohol and urea causes solute diuresis.

Too much sodium input (10%):

Commonly used in the injection of NaHCO3, excessive input of hypertonic NaCl, etc., patients with more severe blood volume.

Kidney sodium reduction (10%):

Found in right heart failure, nephrotic syndrome, cirrhosis, ascites and other pre-renal oliguria; acute and chronic renal failure and other renal oliguria, metabolic acidosis, cardiopulmonary resuscitation and other supplemental alkali; elderly or infant kidney function Poor, Cushing's syndrome, primary aldosteronism and other potassium-sparing diseases; use of deoxycorticosterone, licorice potassium and sodium retention drugs.

Hypernatremia prevention

1. Based on prevention, the electrolyte, blood sugar, liver and kidney function are frequently monitored during treatment.

2. Active treatment to control the primary disease.

3. Appropriate control of sodium and water intake to maintain blood sodium levels in the normal range.

Hypernatremia complications Complications, hypercapnia, hyperkalemia, dehydration shock

Clinically, the water balance and sodium balance disorder are often mixed type, which may be sodium deficiency combined with water shortage or high sodium combined with excessive water; it may also be sodium deficiency combined with excessive water or high sodium combined with water shortage, so the medical history should be comprehensively analyzed. Clinical manifestations and laboratory test results, grasping the primary factors and major contradictions.

1. Hyperglycemia caused by severe infection in diabetic patients

Through diet control and oral hypoglycemic drugs, most patients can maintain normal blood sugar levels in normal times. Once they are infected, they are prone to severe hyperglycemia and hypernatremia. The causes of hyperglycemia are: 1 stress response, adrenal gland The levels of corticosteroids, growth hormone, glucagon, etc. are significantly elevated, and inhibit the action of insulin, resulting in a significant increase in blood glucose. 2 tissue cells have decreased sensitivity to insulin. 3 catabolism enhanced, the synthesis of glycogen, the ability to lower blood sugar decreased. 4 severely infected patients need sufficient energy supply, can not carry out dietary restrictions, patients can have severe hyperglycemia in a short period of time, but not necessarily ketoacidosis, continue to apply oral hypoglycemic agents and general insulin treatment can not control, Significant hyperglycemia leads to a significant increase in plasma osmotic pressure, resulting in osmotic diuretic effect, loss of electrolytes less than the loss of water, resulting in concentrated hypernatremia, with a certain degree of sodium loss; patients with severe infections combined High fever and high catabolism, large loss of water in the respiratory tract and skin, further aggravating concentrated hypernatremia; diabetic patients are mostly elderly, diabetes and old age are easy to combine with the decline of renal tubular concentrating function, resulting in a further proportion of drainage Excessive sodium excretion, aggravating concentrated hypernatremia; infusion therapy such as anti-infection or hypoglycemia often enters physiological saline or 5% glucose normal saline intentionally or unintentionally, resulting in an increase in blood sodium, due to blood concentration and renal blood The flow rate is reduced, and the patients are complicated with high chlorine, hyperkalemia and elevated urea nitrogen. Signs of dehydration.

(1) Principles of treatment: elevated blood sugar is the basis of hypernatremia. Blood concentration is the main factor for hypernatremia, and the input of sodium ions is often an important factor for further aggravation. Therefore, blood sugar should be controlled and fluid replacement should be increased. Quantity, limiting the input of sodium ions.

(2) Controlling blood sugar: Applying a larger dose of insulin, in order to control the rate of blood glucose decline, intravenous infusion should be used to avoid subcutaneous injection. In theory and habitually, physiological saline should be input. After the blood sugar drops significantly, use 5%. The glucose solution should be noted to ensure that the blood glucose concentration gradually decreases. If it cannot be effectively decreased, with the input of physiological saline, the high sodium and hyperosmolar may be further aggravated. If there are conditions, the micro pump may be used for injection. Control the amount of sodium chloride, of course, the rate of decline in blood glucose concentration should not be too fast, otherwise it will lead to a rapid decrease in plasma osmotic pressure, a large amount of water into the red blood cells, hemolysis, brain edema, and hypovolemic shock Danger, after the blood glucose concentration drops to 8 ~ 12mmol / L, it is considered to reach an appropriate level, does not need, should not fall to normal levels.

(3) Increase the amount of fluid replacement: In patients with unstable blood pressure, the colloid should be input at the same time; in patients with stable blood pressure, the water intake and input should be increased rapidly. The common intravenous rehydration solution is mostly 5% glucose solution and normal saline, which is difficult to control. The input of sugar and sodium ions should be based on intake. Patients who can enter the water independently can drink water by themselves; otherwise, they should be supplemented by gastric tube. Of course, hypotonic glucose and hypotonic sodium chloride solution can also pass through the vein. supplement.

(4) Controlling the amount of sodium ions: The above measures can better control the amount of sodium ions, but with the control of blood sugar and the improvement of body fluid volume, the concentration of sodium, potassium and chloride ions may be accompanied by these ions. When the blood concentration reaches the normal low level, the supplement of sodium chloride and potassium chloride should be increased, otherwise it will lead to low sodium, low chlorine and hypokalemia.

(5) Check of blood sugar and electrolyte: It should be checked once every 2 hours, and the number of inspections should be reduced after the condition is stable.

2. Severe lung infection or acute lung injury complicated by hypernatremia

The patient's respiratory tract and skin lose a lot of water, which easily leads to concentrated hypernatremia. Patients who establish artificial airway lose more water. Infusion therapy such as anti-infection often also inputs saline or 5% glucose normal saline intentionally or unintentionally. Lead to the increase in the trueness of blood sodium, so patients with mixed hypernatremia, should be a large amount of water, supplemented by gastrointestinal tract, after the improvement of blood volume, on the one hand rehydration, on the one hand diuretic.

3. Cerebrovascular accident in the elderly with hypernatremia

(1) Cerebrovascular accidents easily affect the endocrine function of the hypothalamus and pituitary, resulting in a decrease in renal sodium excretion.

(2) The renal tubular function of the elderly is mostly reduced, and the function of sodium ion is adjusted to decrease.

(3) often combined with tracheotomy, increased respiratory dehydration.

(4) The thirst central function is lost or insensitive, and in the case of elevated blood sodium, water intake cannot be increased.

(5) Commonly used osmotic diuretics, the loss of water is more than the loss of electrolyte.

(6) Intake of sodium ions (ordinary diet or nasal feeding) and input are often not effectively controlled.

(7) Nasal feeding high protein diet is prone to concentrated hypernatremia.

(8) There are many comorbidities or complications, so mixed hypernatremia often occurs.

Treatment principle: Mainly to prevent, often review electrolytes, blood sugar and liver and kidney function, properly control the intake of sodium and water, avoid the rapid decline of blood sodium, and maintain the blood sodium level at the normal low limit; once the blood sodium is found At the normal high limit, it should be treated in time, otherwise hypernatremia is prone to occur.

Water and sodium balance disorders are often accompanied by other electrolyte disturbances and acid-base balance disorders. Attention should be paid to the relationship between various ions and comprehensive treatment.

Symptoms of hypernatremia common symptoms hypertension, hypoxia, hypokalemia, irritability, restlessness, sodium accumulation, nausea and vomiting

History

Thirsty, reduced water intake and urine output.

2. Signs

Including signs of dehydration, blood pressure and pulse rate, changes in consciousness, increased muscle tone and hyperreflexia.

3. Laboratory inspection

Including blood sodium, blood, urine osmotic pressure, if blood sodium > 150mmol / L, plasma osmotic pressure > 295mOsm / kg, and urine osmotic pressure <300mOsm / kg, suggesting that ADH release or its target target defects; if urine osmotic pressure >800mOsm/kg, indicating that the renal tubular concentrating function is normal, suggesting that hypernatremia is caused by sodium excretion disorder (or retention hypernatremia). If blood percolation is higher than urinary exudation, it is mostly central or kidney. Diabetes insipidus.

Hypernatremia check

1 commonly used blood test indicators

(1) Serum sodium concentration: increased, greater than 145mmol / L, mostly accompanied by hyperchloremia, and the degree of increase is generally the same.

(2) Plasma crystal osmotic pressure: increased.

(3) Blood volume: normal or elevated, red blood cell count, hemoglobin, plasma protein and hematocrit are basically normal or slightly decreased.

(4) Red blood cell morphology: The red blood cell volume is reduced, and the average red blood cell hemoglobin concentration is increased.

2. Common urine test indicators

(1) Urine sodium concentration: increased significantly, but the number of patients in the early stage of stress response decreased, and the concentration of urinary sodium decreased in endocrine disorders.

(2) Urinary chlorine concentration: consistent with changes in urine sodium concentration.

(3) Urinary osmotic pressure and relative density of urine: consistent with changes in urinary sodium concentration, most patients have increased water absorption due to increased sodium chloride excretion, osmotic pressure and relative density are significantly increased; endocrine disorders, urine osmotic pressure And relatively low density.

3. Cerebrospinal fluid examination: Red blood cells and protein may be found in some patients.

4. Do brain CT examination if necessary.

Diagnosis and differentiation of hypernatremia

diagnosis

1. History of thirst, drinking water and urine output decreased.

2. Signs include signs of dehydration, blood pressure and pulse rate, and changes in consciousness. Increased muscle tone and hyperreflexia.

3. Laboratory tests include blood sodium, blood, and urine osmotic pressure. If the blood sodium is >150mmol/L, the plasma osmotic pressure is >295mOsm/kg, and the urine osmotic pressure is <300mOsm/kg, it indicates the release of ADH or its target organ defect; if the urine osmotic pressure is >800mOsm/kg, the renal tubular concentration function Normal, suggesting that hypernatremia is caused by sodium excretion disorder (or retention hypernatremia). If the blood infiltration is higher than the urine, it is mostly central or renal diabetes insipidus.

Differential diagnosis

Hypernatinemia and septic hypernatremia are quite different.

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